POPULAR BOTANY A.E.KNIGHTANDEDWJ® STEP THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA LOS ANGELES THE LIVING PLANT FROM SEED TO FRUIT BLOOD-LIPPED O.XCll) (Oncidium htematochilum). 'he Oncids are a large group of Orchids, natives of tropical America and the West Indies. They all grow upon trees epiphytes) and exhibit great variety of form and colour. The species figured is a native of New Grenada. The leaves POPULAR BOTANY THE LIVING PLANT FROM SEED TO FRUIT BY A. E. KNIGHT AND EDWARD STEP, F.LS. VOLUME II WITH 721 BEAUTIFUL ILLUSTRATIONS AND 18 COLORED PLATES NEW YORK HENRY HOLT AND COMPANY PRINTED IN GREAT BRITAIN 50 PAGE 289 VOL. II. CONTENTS. CHAPTER X. THE LEAF IN RELATION TO ITS ENVIRONMENT (continued) .... XI. FLORAL FORMS AND THEIR RELATIONS TO INSECTS 312 XII. THE WELCOME OF THE FLOWERS 358 XIII. SOME PLANT MARRIAGES AND THE GUESTS THAT ASSIST AT THE FUNCTION . 422 XIV. THE PROMISE OF THE PLANT THAT is TO BE . . . . . . 464 XV. HIDDEN MARRIAGES 500 GLOSSARY OF TERMS 574 INDEX . .577 COLOURED PLATES. Blood-lipped Oncid (Oncidium hcematochilum) Frontispiece Facing page Peach (Prunus persica) 289 Rosy Garlic (Allium acuminatum) Close-headed Befaria (Be/aria coarctata) Variegated Oncid (Oncidium variegatum) 321 353 385 Blue Vanda (Vanda ccerulea) . . . . . . . . . . .417 Cervantes' Odontoglot (Odontoglossum cervantesii) ....... 449 Speckled Odontoglot (Odontoglossum ncevium) ........ 481 Toothed Ceanothus (Ceanothus dentatus) 513 ILLUSTRATIONS IN THE TEXT. PAGE Alder . . . .514 PAGE Barberry . . . .405 PAGE Buttercups, Section showing PAGE Clematis caerulea, Flower of 328 Alocasia speetabilis . . 443 Bedeguar Gall, Flowering receptacle to which the — Garden . . .335- Antheridium, An . . 505 Branch of a Rose sur carpels are attached . 322 Climbing Cobaea, Section of Antherozoids . . .500 rounded by a 304 Cabbage, Skunk . . 387 flower in first stage of Anthers and their Dehiscence 354 Beech, Hairy Galls on. 305 Cactus, A Prickly Pear . 300 development ; and fruit 373 Apple . . . 357, 473 Begonia, Abnormal Flower o 324 Calla, Marsh . .361, 441 Section of flower in third Aralia nudicanlis, Flower- — Section of . 332 Campion, White. . 340, 446 stage of development 373 buds of ... 386 Bellflower, Xettle-leaved 425 Candytuft, Evergreen . 486 Clubs, Fairy 549 Arbor-vita?, Cone of Chinese 489 Birth wort . 374 Carrot . . . .332 Cluster-cups 546 Archegonium, An . . 505 Bleeding Heart . 320 Catasetum tridentatum 408, 409 — Hawthorn 550 Arum, Giant . . .317 Brefeldia maxima . 570 Caterpillar-plant . . 481 Coco-nut, Double 488 Asclepias cornuti, Pollinia of 408 Ash . . 368 Burweed . 486 321 Chestnut, Horse . . 479 — Section of (Male Flower). 366 Columbine . Comfrey 348 407 Aspen . . . .448 — Apocarpous fruits . 334 - Sweet . . 367, 462 Convolvulus, Seaside 345 Aspidistra . . . .376 — from below . 321 Chrysanthemum, Annual . 352 Corallina officinalis 553 Balsam . . . .442 — Rosaceous Corolla of 342 Clavaria, Crested . . 538 Corncockle 474, 496 Illustrations in the Text, Vol. II. Cotton-grass Cowslip Cranesbill, Meadow — Blood-Red . Creeper, Rangoon Crocus — Indian . Lip of flower showing fringes ai Hairs of two of the tip highly magnifled Cuckoo-flower Cuckoo-pint Cucumber, Squirting . Cyclamen . Cyperus, False . Dandelion . — Floret of Dead-nettle, White Dewberry . Dog Lichen Dragon's-mouth, Mountain Dry Rot . Earth-Nut Ergot Fern, Cup-shaped Indusium of Filmy . — Hard . — Male — Prickly Buckler — Sea — Spores Germinating Fig . . Figwort Flamingo Plant . Flowers, Estivation of Forget-me-not . Foxglove . Fuchsia . Fungus, Bird's-nest — Candle-snuff . — Jew's-ear Ginger, Wild . Goatsbeard Gourd Grape Vine Great Panicled Se Pollen-grains of Gum-Arabic Tree Gymnosporangium clavariio- forme . Hairs from the Leaves of Various Plants (Magni- fied) . Hard Heads Hazel — Flowers Heath , Hispid . Heather or Ling Helleborine, Broa Henbane . Henbit Herb-paris . Holly — Hedgehog Variety of Halymenia ligulata Honesty . Hop Hornbeam . Horehound, Black Hornbeam PAGE . 453 . 315 . 374 . 494 PAGE Horn of Plenty . . .548 Horse Chestnut . . 366, 479 Horsetail . . . .512 — Field . » . 514, 515 PAGE Oak, Bristle-gills on . . 302 — Cherry-galls on . . 301 — Spangle-galls on . . 301 — Turkey . . . .495 PAOE Sallow . . . .369 Samphire . . . .493 Saxifrage . 394 — Mossy . . . .383 Seaweed, A Red . , 553 . 334 . 380 Inflorescences, Definite 327 Oat 316 Odontoglossum alexandrse , 412 — Ash -leaved . . . 559 — Forked . , . 563 howing — Indefinite 331 Oncid, Tiger-striped . . 384 Sensitive Plant . . . 292 ;aks of Iris •177 Orange, Myrtle-leaved . 490 Snapdragon, A portion of the lides . 382 Jania rub ens 557 Orchis, Bird's-nest . . 437 stigma and style . 326 tion of Jericho, Rose of 485 — Butterfly . . .426 — Section through pistil 01 322 =1 of the Job's Tears 493 — Dwarf . . . .432 Snowdrop . . . . 359 led . 382 Kalmia latifolia, Flower of . 406 — Goodyer's . . .431 Sorrel, Common . . 458 . 393 Lady's Tresses . 419 — Green-man . . 433 Sparassis, The . . . 539 . 313 Lapageria, Section of. 444 — Green-winged . '. 436 Spear Plume-thistle . . 299 . 469 Larkspur . . 390, 481, 496 — Fragrant . . . 435 Spleenwort, Maidenhair . 500 . 360 — Garden .... 339 — Musk . . . .440 Stamens of (a) Litsaea ; (6) . 459 Leocarpus fragilis 573 — Purple . . . .434 Pyrola; (c) Garcinia . 356 . 467, 492 Leptodermis lanceolata 498 — Pyramidal . . .438 Star, Earth . . .537 . 329 Lichen, A . 527 — Spotted . 427, 429, 430 Stinging Hair of Stinging . 346 — Sections through . 52S Ovaries, Uniovular . . 465 Nettle . . .296 . 471 Lily, African . 395 Oxlip . . . .376 Stinging Nettle . . .303 . 533 Liverwort . . 522, 526 Pseony, Follicles of . .481 Stock . . . .482 ntain . 391 Loosestrife, Creeping . 312 Pansy Flower, Section of . 392 Stonewort .... 552 . 542 — Purple . . . 363, 377 Papilionaceous corolla . 348 Stork's-bill, Hemlock . 423, 424 . 484 -• — Illustrating the tri- Pasque-flower, Section of . 396 Strawberry . . .472 . 541 dusium flowers 378 Pea, Campylotropous Ovule Tangle, Sugar . . . 554 . 506 Lousewort, Marsh 365 of . . .466 Teasel . . . .297 . 501 Lucerne .... 4S2 — Common . . .330 Telegraph -plant . . . 293 . 502, 503 Lupin .... 4S2 — Flower of ... 402 Thorn-apple . . .476 . 507 — Leaves of ... 289 Pea Flower, Section of . 402 Toadflax, Ivy-leaved . . 483 . 511 Magnolia .... 379 — Gall, Spiked . . 308 — Yellow . . . .349 . 504 Mallow, Common I'll Peacock's-fciil . . .560 Toadstool, The Solitary . 536 . 388 Marigold, Marsh. 362 Petty Spurge, Inflorescence 6f 396 Touch-me-not Balsam Ex- . 350 Meadow-saffron . 477 Pillwort . 509, 510, 512, 513 pelling its Seeds . . 470 . 399 Meadowsweet, American 323 Pimpernel .... 478 Tremella mesenteries . . 544 f . 329 Medlar . . . 473, 175 Pine, Austrian . .451, 499 Trichia varia . . .569 . 385 Megarrhiza calif ornica, Spiny — Scots . . 449, 450 Trigonia villosa . . .498 . 343 Fruit of ... 466 Pink 318 Twayblade . . .401, 420 . 310 Milk-thistle 489 — Mossy .... 344 Urchin Crowfoot . . 490 . 546 Mitrula phalloides 545 Pistils . . . .355 Valerian, Great . . 341 . 547 Monkshood 336 Plantain, Large . . .457 Vallisneria spiralis . .413 . 540 Moonwort .... 50S — Lamb's-ear . . . 381 — Flowers of ... 414 . 403 Morel .... 543 Plants, Lime -secreting . 556 Violet, Sweet .. . . 358 . 319, 364 Morning Glory . ;>7.'> Plumbago . . . .360 Water-dock, Great . . 455 . 489 Moss, A Scale . 524 Plume, The Crimson . . 557 Water-lily, White . . 464 . 344, 463 — Beard .... 529 Plum, Section through a .488 Wheat . . . .492 ge, . 454 — Common Club . -Cup .... •")! 7 630 Plums, Yellow, Fruit of the White Campion . . 340, 446 Whortle-berry . . .344 485 — Hair . . . 520, 523 American Plum-tree . 487 Willow-herb, Great . . 372 ivariie- — Lesser Alpine Club 517 Pollen-grain Magnified . 454 Winter Cherry . . . 341 . 551 — Marsh Club . 516 — of Evening Primrose . 400 Wistaria, Abnormal Flower of 324 ves of — Screw .... 521 — Passion Flower . . 400 " Witches Broom " on Scots Magni- Mosses, Two 525 — Pumpkin . . .400 Pine . . . .309 . 295 Mould, Brown . 534 — Scot's Pine . . .400 Wood Anemone , . 417 . 371 . 456, 491 Mucilago spongiosa Mulberry 473 Polysiphonia . . .558 — Rush, Field . . . 418 . 416 Mullein, Black . 291 Potato-blight . . .532 — Sorrel . . . .290 . 350 Myosotis Flowers. 370 Primrose, Bird's-eye . . 389 — Expelling its Seeds . 468 . 447 Myxomycete, Development Primula obconica . . 307 Seed of ... 469 aved . 421 of a , 571 Prothallium, A . . .504 — Spurge . . . .397 . 338, 353 Nail-galls .... 306 Pternandra cordata . . 338 Wrack, Bladder 562, 564, 565 . 370 Nasturtium . . 337, 494 Pull-balls, A Cluster of . 535 — Saw-Edged . . .555 . 314 — with spurred calyx 337 Purse, Shepherd's . . 37u Wych Elm . . .493 . 398 Nectar Glands . 398 Quillwort .... 518 Yarrow .... 445 of . 296 Nectaries .... 390 Ramalina scopulorum . „ 531 Yew . . 497, 498 . 561 Needle Whin . 428 Hampion . . . ,347 Yoke-thread . . .566 . 340, 485 Nettle, Flower of 414 Rose, Dog- and Field- . 333 Yucca, Flower of . . 410 . 497 . 493 Nut, Brazil Oak •ISO Sage, Flower of . . 404 — Moth . . . .410 . 461 — Apple . 311 flowered . . .325 Gathering Pollen . 410 — Plant . . . 411, 439 PEACH (Prmim penica). The Peach is believed to have come originally from China, but has been cultivated in Europe from very ancient days, and in this country from the middle of the sixteenth century. It belongs to the same family as the Plums and SH The varieties represented are semi-doubles, cultivated more for the flowers than for fruit. CHAPTER X THE LEAF IX RELATION TO ITS EX VIROXM EXT— (Continued} THOSE who have never studied under the microscope the singular forms of the covering hairs of leaves, have pleasures offered to them for many a winter evening. Possibly a glance at the illustrations which ac- company this part of our text will help to kindle interest in the subject. Eig. 3606 represents some simple hairs of a species of Brassica-, i some forked hairs of the Whitlow Grass (Draba verna] ; and A a stellate hair of the pretty Alpine Madwort (Alyssum spinosum). In these three specimens the hairs are unicellular, but multicellular hairs are met with in a large number of plants. When the cells grow together in a line, like the beads of a necklace, the hairs are said to be moniliform. Of this kind are the epidermal hairs of the Marvel of Peru (Mir a- flrst shows the position of the- leaflets tiurincr the day; at night they fold down close to the stalk. pfii fig. 360 j) and of the Virginian Spider wort {Tradescantia virginica, k). AVhen the cells spring from a common point, as in the Cretan Horehound (\larru- bium cwticum, e\ the hairs FlG- 352.— LEAVES OF LUPIN. are said to be tufted. Branched hairs, which need no describing, are found in several plants. They give the downy (toinen- tose} appearance to the leaves of Xicandra anomala, a Peruvian plant of medicinal value (/), and to the decurrent leaves of the Great Mullein ( Ver- bascum thapsus). In a few plants of succulent habit, like the South African Bocheas, excessive evaporation is prevented b}^ the development of special flinty cells on the epidermis of the thick fleshy leaves (g). They are many times larger than the ordinary epidermal cells, and their walls are largely composed of silica. A covering of this kind is simply the salvation of its possessor in time of drought. Not that fleshy leaves are ill-adapted to II— 1 289 HUTCHINSON'S POPULAR BOTANY FIG. 353. — WOOD-SORREL (Oxalis). During the day the leaflets spread out from the leaf-stalk ; Fia. 354. — WOOD-SORREL. —at night, and duiing rain, they fold down close to the leaf-stalk. dry climates ; the reverse is the case, the transpiring surface of such leaves being much smaller than if they were flattened out into thin and spreading forms. Yet even the smaller surface needs to be protected, and this it is which gives its value to the flinty armour. The vertical position which many leaves assume is likewise a means of checking excessive trans- piration. One has met with the expression, " the shadoidess forests of Australia," and the phrase is not inappropriate, for the leaves of many Eucalyptus-trees and Acacias (the chief timber trees in Aus- tralian woods) do not assume a horizontal position like the leaves of most European forest-trees, but are placed vertically on edge ; and thus the shadows which they cast at midday are reduced to a mere line. This, as we need scarcely add, is due to the fact that the rays of light fall upon the up- turned edges of the leaves and not upon the broad surfaces of the blades.* The latter, indeed, escape altogether the meridian sun, though they get the full benefit of his less scorching rays at the beginning and close of the day. The interesting Compass-plant (Silphium laeiniatum) should not be forgotten when speaking of the position assumed by leaves in refer- ence to transpiration. Longfellow's Evangdine contains a graceful de- scription of the plant (though he confuses flower and leaf), which * This is also a protection from the in- jurious effect on the chlorophyll corpuscles of the intense sunlight. Photo J>y] FIG. 355. — BLACK MULLEIN (Verbascum nigrum). [E. Step. The leaves are downy with a dense growth of stellate hairs. The yellow flowers are closely packed in long racemes which are a foot and a half long. EUROPE, SIBERIA. 291 292 HUTCHINSON'S POPULAR BOTANY FIG. 356. — SENSITIVE PLANT (Mimosa pudica). Day position of leaf and leaflets. specimens of this plant not only assume an almost vertical position, but by a singular twisting of their blades, bring themselves into a position which has earned it the name of Compass-plant. The lobes of each pinnate- parted leaf, extending like fingers on either side of the midrib, are said to point due north and south ; but some observers who have watched the plant in its native habitat have thrown considerable doubt upon the state- ment, as they have found the leaves point- ing in all directions. The leaves of the Marram (Psamma aren- aria) exhibit a special structure in view of this same purpose — the prevention of ex- cessive loss of water. The plant in ques- tion is the Common Matweed of our sand- hills, whose spreading fibrous roots are so useful in binding together the shifting sands on the coasts of Norfolk and Holland, and in many other places. It has been noted that " on wet days the leaves open longi- tudinally, so that their inner surface is freely exposed to the air, and the stomata which are situated there may not have their func- is widely distributed over the North Ameri- can prairies : Look at this delicate plant that lifts its head from the meadow, See how its leaves all point , to the north, as true as the magnet ; It is the Compass-flower, that the finger of God has suspended Here on its fragile stalk, to direct the traveller's journey Over the sea-like, pathless, limitless waste of the desert. The leaves of young FIG. 357. — SENSITIVE PLANT. At night, or when touched, the leaf hangs down, and the leaflets fold closely together. THE LEAF IN RELATION TO ITS ENVIRONMENT 293 tions restricted ; in dry weather, on the con- trary, the leaves are rolled up so that the leaf almost forms a tube, the outer surface of which is hard and quite impervious to water." The mechanism by which this is effected is to be found in certain cells, which form longitudinal rows at the base of the furrows on the under surface of the leaves, and which are very sensi- tive to moisture. In damp weather the cells increase in turgid ity by absorption of water, and the leaf opens. In concluding these observations on the dangers to plants from excessive heat, and the means provided by Nature to counteract those dangers, one is naturally led to the op- posite side of the sub- ject, and the question arises, If too much heat be injurious to a plant, may not, under contrary circumstances, too great loss of heat be injurious too ? Moreover, if the all-wise Mother has devised means for protecting growing plants from the one evil, may she not also have devised means for protecting them from the other '? To both questions an affirmative answer may be given. Loss of heat has no less to be provided against than excessive transpiration — the damp and chilly nights must be taken into account quite as carefully as the dry and sunny days ; for growth goes on in the plant more rapidly in some cases by night than by day, and if it were systematically deprived of heat during the hours of darkness, it would soon languish and die. Now the means which Nature has devised for protecting growing plants from loss of heat FIG. 358. — TELEGRAPH-PLANT (Desmodium gyrans). The small lateral leaflets move up and down, twisting at the same time, and influenced by temperature. 294 HUTCHINSON'S POPULAR BOTANY are beautifully simple. What is known as the "sleep" of plants — in other words, the nocturnal drooping and folding of leaves and flowers— com- prehends the chief of those means, and we shall here confine our re- marks to this well-known phenome- non. If you have ever sauntered through a garden by night, and examined, lantern in hand, the dew-drenched vegetation, you will have stumbled upon some curious discoveries. It is easy to imagine the surprise evoked during such an excursion. As you pause before one of the well-ordered beds, and look down at the familiar plants, you involuntarily ask yourself, What has become of the flowers ? A few, indeed, are still plainly visi- ble ; but there are others that you miss, nor do you realise what has become of them until, on closer ex- amination, you discover that some are closed, and others are hanging down their heads so that only their green collars (the calyces) meet the eye ; while others, again, have skil- fully concealed themselves behind their own foliage leaves. The leaves, too, appear to be wonderfully changed. " We are all a-noddin', nid-nid-noddin'," seems to be their drowsy language. The Tropoeolums no longer confront the vault of heaven with their green shields, which hang listless at their sides ; the Lupins have folded up their digitate leaves like umbrellas (fig. 352) ; and on every hand the foliage seems heavy with slumber. It may be cruel to unsettle so pleasing a fancy, but the phenomenon described, and which is popularly known as the sleep of plants, is simply a part of Nature's plan for guarding Photo by] [E. Step. FIG. 359. — OAK-WEED (Laminaria digitata), One of the largest of our native seaweeds. The specimens photographed were fifteen feet long. FIG. 360. — HAIRS FROM THE LEAVES OF VARIOUS PLANTS (MAGNIFIED). (a) Glandular hairs of Snapdragon ; (6) simple unicellular hairs of a Brassica ; (c) glandular tentacle of Sundew ; (rf) sessile gland of Hop ; O) tufted hairs of Cretan Ilorehonnd ; (0 branched hairs of KicRiidra ; (?) flinty covering of Rochea ; (h) stellate hair of Alpine JIadwort ; (i) forked hairs of Whitlow Grass ; (/) muriform hairs of Marvel of Peru ; (t) muriform hairs of Virginian SpHerwort. 295 296 HUTCHINSON'S POPULAR BOTANY FIG. 361.— STINGING HAIR OF STINGING NETTLE. her vegetable proteges against excessive loss of heat. The " sleep " position of leaves is, in fact, a protective arrangement. By folding themselves together and as- suming, as far as possible, a vertical position, radiation is materially checked, and thus the plants undergo no serious fall of temperature daring the night. We must not be misled "by this popular term "sleep" into sup- posing that the nutritive processes of the plant are suspended at this time. " The drooping position as- sumed by the leaflets of Oxctlis is simply protective : there is no correlation between the assumption of the drooping position and the temporary loss of the power of assimila- tion. Preparations made at night from the leaves of Oxalis when in the drooping nyctitropic position show a normally active power of assimilation, and the same is the case with leaflets of Mimosa, The movements per- formed in assuming the nocturnal nyctitropic position of certain ' sleep ' plants are not accompanied by any corresponding internal changes or alterations in the power of assimilation. In this respect the sleep of plants is more external and apparent than, internal arid real '; (A. J. Ewart, B.Sc., in Journ. Linn. Soc. [Botany], vol. xxxi., 1896). Plants of the great Leguminous order, to which the Acacias, Mimosas, Peas, and Trefoils belong, exhibit the phenomenon of which we are treating in a very striking manner. The Wood-sorrels (Oxalis acetosella, corniculuta, and stricta], also, are extremely sensitive to changes of temperature, folding down their leaves even in the daytime if rain threatens (figs. 353, 354), while a blow from a stick will cause them to shrink together with affecting suddenness. Sensitiveness is carried to an extreme in a tropical species of this genus, Oxalis sensitiva, concerning which it is affirmed that even the disturbances of the air caused by the approach of man are sufficient to- induce the phenomenon, the petioles relaxing and the pinnate leaflets falling together like the leaves of a book. This is also said to be the case with several of the Mimosas ; but the two- species which are most common in English stove-houses (M. pudica, figs. 356, 357, and M. sensitiva), though collapsing readily at the slightest touch, certainly do not exhibit such FIG. 362.— HEDGEHOG VARIETY OF HOLLY. extreme sensibility in this THE LEAF IN RELATION TO ITS ENVIRONMENT 297 country. Touch a leaf-point of Mimosa, and the small leaflets fold togetherr and the stalk to which they are attached drops suddenly. The leaflets on other branches of the compound leaf act in the same way; and finally the main leaf-stalk drops suddenly. The Mimosas have received poetic treatment from more than one distinguished writer. Erasmus Darwin says : Weak with nice sense the chaste Mimosa stands, From each rude touch with- / draws her timid hands ; Oft as light clouds o'erpass the summer glade, Alarmed she trembles at the moving shade ; And feels, alive through all her tender form, The whispered murmurs of the gathering storm ; Shuts her sweet eyelids to approaching night, And hails with freshened charms the rising light. The movements of so-called sensitive plants are probably in part due to a peculiar modifica- tion of certain of their leaf-cells, which — in the Mimosas.' at least — are so constructed that delicate threads of pro- toplasm pass through their walls and maintain a connection with the living matter of adjoin- ing cells. Thus the effects of a touch on one part of a leaf may be transmitted all over it ; and if, as is not un- likely, these perforated cells are distributed through the stem and branches as well as the leaves, the effects spoken of may be carried to every part of the plant. The drooping of the leaf-stalk (which, as in the leaf of Mimosa pudica, may alter its angle with the stein from ninety to thirty degrees) is caused by a beautiful piece of mechanism. At the base of the leaf-stalk there is Photo by] [E. Step. FIG. 363. — TEASEL (Dipsacus sylvestris). Showing the protective spines on the stem, and the spiny bracts inter- spersed with the flowersiin the flower-head. 298 HUTCHINSON'S POPULAR BOTANY a little cushion-like swelling, called the pulvinus (the Latin word for "cushion"), which contains a woody centre surrounded by parenchymatous cells, rich in water. When one of the pinnate leaflets is touched, the effect is transmitted to the pulvinus by the threads of protoplasm, with the result that the water passes from the cells on the lower to those on the upper side, causing the former to pass from a distended into a flabby state. They thus become temporarily unfit to support the leaf-stalk, which in [E. Step. FIG. 3C4. — HOLLY (Ilex aquifolium). Showing the spiny, dentate leaves and the clusters of red berrii consequence falls of its own weight. By and by the water gains its original distribution, and then the leaf-stalk resumes its horizontal position. The celebrated Telegraph-plant (Desmodium gyrans) is even more interesting than the Mimosas. It is an East Indian plant with violet flowers and trifoliate leaves, and the latter are in motion night and day. In bright sunshine the two lateral leaflets jerk up and down, and from side to side, in a remarkable manner, while the large terminal leaflet goes through similar though less perceptible movements (fig. 358). Should these movements be artificially checked for a while, the leaf will start again with increased velocity directly the retarding influence is removed. During darkness the [Henry Irving, FIG. 365. — SPEAK PLUME-THISTLE (Gnicus lanceolatus). Airparts of tl.e plant above ground are armed with needle-like spines. The florets are specially adapted for the visits of bees with long probosces, particularly humble-bees. 299 300 HUTCHINSON'S POPULAR BOTANY terminal leaflet assumes the perpendicular position which has been already shown to be characteristic of " sleeping " leaves. The trembling movement of the leaves of the Aspen (Popidus tremida) has supplied many figurative allusions to prose-writers and poets, and the phenomenon deserves a passing notice. The quivering is due to the elasticity of the long flattened foot-stalks ; and Mr. Colbourn, of Hobart, suggests that the rapid movement in the air enables the leaf to throw off the excess of moisture which collects on it in the damp situations of the tree. Some force is given to this view if we look at tho Aspen or the Black Poplar immediately after rain, when we shall find great numbers of the leaves held together by moisture. Kerner, however, regards the motion as an arrangement for protecting the flat broad leaves against crushing ; but many other broad flat leaves are without this provision. He further remarks that the elasticity is due to the development of bast-strands in the leaf-stalks. We have now considered a few of the dan- gers to which the green leaves of plants are exposed, but the subject would be very im- perfectly treated were no mention made of a danger of another kind. This form of danger belongs to the animate rather than the inani- mate world — to " wild beasts and beasts of the field and creeping things" rather than to heat and cold and other such phenomena and forces. Innumerable animals feed upon the green tissues of plants, and find in a vegetarian diet their only sustenance ; indeed, if Nature had not provided special contrivances to keep off these devourers, it is next to certain that whole families of plants would long since have van- ished from the face of the earth. A few of these contrivances have been incidentally re- ferred to in former chapters. When speaking of the sap of plants, we showed that the milky juice of the Common Lettuce (Lactuca sativa) pro- tected the plant from the depredations of ants and other leaf-eating insects ; and on a later occasion we saw that the thorns or spines in such plants as the Blackthorn (I'runus spinosa), Spiny Restharrow (Ononis spinosa), Spurges (Euphorbia), etc., render acceptable service by keeping off brows- ing cattle and herbivorous wild animals. But the subject was only lightly touched, and — from the nature of the connection in which it was intro- duced— many of these protective contrivances were not alluded to at all. For example, no mention was made of prickles. Prickles are another kind of thorn. They are not, like spines, branches which have degenerated, FIG. 366. — A PRICKLY PEAK CACTUS (Opuntia multiftora), Protected by fine barbed bristles. THE LEAF IN RELATION TO ITS ENVIRONMENT 301 Photo by] [J. Holmes. FIG. 367. — SPANGLE-GALLS ON OAK. for they spring from the epider- mis or cortex of a plant member, and contain no fi br o- vascular bundles ; while spines, it will be remembered, are trav e r s e d by those bundles which connect them with the vascular system of the stem arid root. Good ex- amples of prickles are offered by the Dog-rose (Rosa canina) and the Holly (Ilex), to name no other plants. In the former they occur on the petioles and branches ; in the latter they spring from the margins of the leaves. Plants of a prickly nature seldom develop those structures on leaves and branches which are out of reach of grazing animals. The Common Holly (Ilex aquifolium), the bristly den- tate leaves of which form a character! stic feature of shrubby speci- mens of the plant, produces only unarmed leaves, with en- tire margins, on its upper branches, when it attains to t h e dignity and di- mensions of a tree. Indeed, the gradations from Photo by] FIG. 368. — CHERRY-GALL ON OAK. [J. Holmes. 302 HUTCHINSON'S POPULAR BOTANY the prickly to the unarmed forms of leaves in the plant named are so numerous and marked, that the species has been separated into varieties to distinguish them. Compare, for example, a leaf of Henderson's Holly (Ilex a. hendersoni) with one of the Doningfcon variety (Ilex a. donington- ensis), and both with a leaf of the Hedgehog Holly (Ilex a. ferox, fig. 362) ; which latter has prickles not only at the margin, but also on the upper surface. Its popular name is, indeed, exceedingly appropriate ; so, too, is its Latin appellative— /mw, " savage.0' Several plants of the large genus Solanum, to which the Potato-plant and Woody Nightshade belong (e.g. S. fontanesianum, jac- quinij and maroniense}, have spiny erections on both sides of the leaf. They are borne upon the midrib and veins, and make the plants ex- tremely awkward things to handle. Many other protective arrangements more or less similar to those described occur readily to the mind ; as, for instance, the sharp, strong, needle-shaped (acicu- lar) leaves of many Grasses ; the formidable thorny ter- minations of the leaves of the Agaves, and the spine- bordered lobes of leaves like the Thistle (Carduus), Teasel (Dipsacus), and Acanthus. It has been asserted that in the- Southern Alps sheep will frequently return from pasture with their nostrils cut and bleeding, and the shepherds know at once that the cause of the mischief is a species of stiff-leaved Grass, Festuca alpestris, which they seek to destroy by burn- ing. In some instances, Grasses which cause discomfort to grazing animals will be dealt with by the animals themselves, who seize them low down with their teeth and tear them from the ground. Kerner saw thousands of tufts of the Mat-grass (Nardus stricta), which had been rooted up by oxen, lying dried and bleached by the sun on some meadows in the Tyrolese Stubaithal. FIG. 369.— BRISTLE-GALL ON OAK. These galls are caused by the gall-wasp, Andricus lu [7. Holmes. FIG. 370. — STINUING NETTLE (Urtica dioica). The leaves and stem are covered with hollow stinging hairs throusrb which a poison is introduced to the victim's flesh. The small green flowers are wind-pollinated. NORTH TEMPERATE REGIONS, X. AFRICA, THE ANDES. 303 304 HUTCHINSON'S POPULAR BOTANY More formidable than airy of the protective weapons yet mentioned are the barbed bristles which surround the buds on many of the Opuntias. Each of these is a sort of compound fish-hook in miniature, and woe to the unwary animal who pushes his nose against the smallest bunch of them! The little hooks enter the tender flesh, and cause intolerable itching, which is often succeeded by painful and, it may be, dangerous inflammation. The tormenting bristles are easily driven deeper, but the backward-pointing barbs tear the flesh unmercifully when any attempt is made to withdraw them. One species, Opuntia ficus-indica, better known as the Prickly Pear, is abundantly naturalized in the Mediterranean area, where it forms inpenetrable fences. Another species, Opuntia feroXj is said by Schleiden to be especially remarkable because of the strength and size of its defen- sive thorns. " Among the hairs and smaller spines," he says, " arise very long and thick spines, in different form and number, which give the best characters for the determination of the species. In some, these are so hard and strong that they even lame the wild asses which in- cautiously wound themselves when kicking off the spines to reach the means to still their thirst. In Opunlia tuna, which is the kind most frequently used for hedges, they are so large that even the buffaloes are killed by the inflam- mation following from these spines running into their breasts. It was this species, also, which was planted in a triple row as a boundary line between the English and French in the island of St. Christopher." Fig. 366 represents a flowering branch of Opuntia multiflora. No account of the protective armature of green leaves would be complete without a reference to stinging hairs. The mention of these very remarkable structures brings to mind the Common Nettle (Urtica dioica) — a weed that is known to every child. Let us take a peep through the microscope at one of its stinging hairs, and try to realise what takes place when any rash FIG. 371. — FLOWERING BRANCH or A ROSE SUR- ROUNDED BY A BEDEGUAR GALL. The gall-fly and grub of same are shown in the corner of drawing. THE LEAF IN EELATION TO ITS ENVIRONMENT 305 meddler with the plant gets stung. Our picture (fig. 361) represents a hair in section. It consists of a long, tapering single cell, rising from a cushion- like base, and widening at the apex into a little knob, which is bent some- what out of the perpendicular. At the point where this bend takes place the cell-wall is extremely thin — so thin that a very slight touch suffices to break off the knob. When, therefore, such a touch is given, the mischief is done, and the acrid irritating fluid contained in the cell escapes at the point of rupture and enters the tiny wound which the vitreous apex of the hair has made. The fluid consists of formic acid and a sort of unorganized ferment or enzyme, the latter being thought to be the more poisonous property of the two. It may be added that the break takes place obliquely (a conse- quence of the bend above described), so that the broken end resembles the poison-fang of a serpent — to which, indeed, it has sometimes been com- pared. A brush from the leaf of any of the British Nettles ( Urtica dioica, tirens, and pilulifera) is doubtless a light matter, but to be stung by some of the Asiatic species is a very different thing. The great Shrubby Nettlfe (Urtica crenulata) of Northern India, for instance, is a nettle to beware of. "This plant," says Sir Joseph Hooker in his Himalayan Journals, " called ' mealum-ma,' attains fifteen feet in height ; it has broad glossy leaves, and though apparently without stings, is held in so great dread that I had difficulty in getting help to cut it down. I gathered many specimens without allowing any part to touch my skin; still, the scentless effluvium was so powerful that mucous matter poured from my eyes and nose all the rest of the afternoon in n— 2 Photo by] [E. Step. FIG. 372. — HAIRY GALLS ON BEECH, Caused by a two-winged fly (Hormomyia). 306 HUTCHINSON'S POPULAR BOTANY such abundance that I had to hold my head over a basin for an hour. The sting is very virulent, producing inflammation ; and to punish a child with ' mealum-ma ' is the severest Lepcha threat." The writer explains in a footnote that the hairs are microscopically small, and they only sting violently during the autumn. M. Leschenault, a French botanist who had the misfortune to be stung by the " mealum-ma " at this particular season, while gathering one of the leaves for his herbarium, describes the symptoms that followed as anything but pleasant. At first he felt only a slight pricking which he wholly disregarded ; but the paiil gradually increased, and at the end of an hour it had become excruciating. The parts affected — the first three fingers of his left hand— felt as though they were being rubbed with a, hot iron. Before long the pain had spread f^*7y*f UP tne arm to the arm-pit ; and within five ^ m hours of being stung the torture was increased , J tenfold by an ominous contraction of the • ^•»-«. M muscles of the jaw, which made him fear an attack of lockjaw. However, the latter symp- toms passed away towards evening, and from that time the pain continued to decrease, though upwards of nine days elapsed before it entirely left him. That the inferior animals are sensitive to the stings of plants no less than man, and therefore that stinging hairs may be a real protection from grazing animals, is illustrated by the fact mentioned by Baillon. that the natives of Java rub buffaloes with a species of Nettle (Urtica stimulans) in order to excite them to fight with tigers. On the other hand, FIG. 373 —NAIL-GALLS these vegetable fangs are innocuous to certain on leaf of Lime, produced by a mite. leaf-eating insects, which feed upon them with impunity ; indeed, it is well known that the leaves of our British Nettles, which are all furnished with stinging hairs, form the only food of the caterpillars of three of our most beautiful butterflies — namely, Vanessa atalanta, V. io, and V. urticae. But this fact affords us a very striking object-lesson on the way in which an offensive or merely defensive development in one organism may lead to the very con- siderable adaptation in some other organism that may bs seriously affected by it. The three caterpillars named have developed protecting spines which keep the stinging hairs of the Nettle from contact with their tender skins. Their relative, Pyrameis cardui, which feeds on Thistles, is similarly protected. It is remarkable that, so far as we have read, botanical writers have failed to note that hairs similar to those of the Nettle, but in a far [E. Sltp. FIG. 374. — Primula ctccnica. Tins bsiutiful plant is coverei with eisily detachable hairs. If these, by incautious handling, come in contact with the humin skin, they set up an iniUmoiitioa very similar to eczema, for which it has been often mistaken. 307 308 HUTCHINSON'S POPULAR BOTANY less highly developed condi- tion, are found on the leaves and young twigs of the Com- mon Elm (Ulmus campestris}. They are abundant along the Titjf M^~ • ~"^t_ , midrib on the lower surface, fv\ and though they have nothing m - '^: 1^ ^|Bi| like the malignity of the Nettle, ifafftty *'. ' if^H^j^l they cause a considerable ^^^ ^^' ^^^^ amount of irritation to the hands and wrists of those who touch the leaves. The Elm sends up numerous suckers, and all down the bole it throws out new shoots, which would be probably browsed off but for the presence of these hairs. The Elm belongs to the same natural order (Urticaceae) as the Nettle. When investigation has been carried farther it will be shown probably that the hair- structures of many other plants have a protective purpose. Many species of Mullein (Ver- b as cum), for example, have branched radiating hairs which rub off easily when the plant is handled, and, though not stiff or prickly, "remain hanging to the smallest in- equalities on the surface of the disturbing body. If grazing animals bring the mucous membrane of their mouths into contact with the leaves of the Mullein," the nock-like masses of hair adhere to the tongue and palate and produce sensations that can hardly be pleasant (Kerner). The hairs of several species of Primula, also (notably P. obconica), set up an inflammation very like eczema when handled incautiously. It may not be generally known that the singular growths called galls, so often to be seen on the leaves and branches of Flowering Plants, are due to insects. Formerly they were held to be entirely of a vegetable nature, and the insects found in them were thought to have been spon- taneously generated there. Many species of Cynips lay their eggs in the parts named, plunging their exceedingly delicate ovipositors into the soft tissues, and thereby set up local irritation, which induces a responsive action of the protoplasm, and galls are produced. In some cases, how- ever, the development of the gall does not commence until after the egg is Photo by] [J. Hull, FIG. 375. — SPIKED PEA-GALL, On Dog-rose, caused by the gall-wasp, Rhodites nervosa. THE LEAF IN RELATION TO ITS ENVIRONMENT 309 hatched. No tree, probably, furnishes so great a variety of these growths as the Oak (Quercus], on which upwards of one hundred and fifty species have been observed, the well-known oak-apple being one of them. It is pro- duced by the punctures of Dryoteras terminalis. Two species of Oak-gall often to be met with are produced by an insect named Spathegaster bac- carum. Fig. 373 represents a leaf of a species of Lime (Tilia platyphyllos) with little conical excrescences or nail-galls, the work of a microscopic species of Phytoptus (P. tilcB\ whose portrait you will notice just above the leaf. Similar galls, but of a downy nature, occur on the leaves of Beech (Fagus sylvatica), in this case caused by a two-winged fly (Hormomyia piliger). The green (ultimately red), mossy-looking growths called bede- guars, or Robin Redbreast's Pincushion, so common on branches of the Rose, are also of insect origin (fig. 371). The gall-fly (Rhodites rosea) deposits its eggs in the shoot-bud, which presently swells and begins to put out what should be in the natural course three leaves ; but embryo leaves have so little parenchyma between their veins that they fall into threads and thus give the mossy appearance to the galls. On cutting open one of the bedeguars the larvae of the insect will be found in the centre. In all these cases it appears that only the cells of the meristem can give rise to the galls. These growths do not appear to be actually injurious. The galls that are found on Hedge Bed- straw (Galium mollugo] are produced by a minute two-winged fly (Cecidomyia aparine) ; and the ' many-cham- bered gall on young shoots of Spruce (Picea excelsa), that look like half a pine cone, are the work of a Coccus (Kermes). The "Witches Broom " on the Scots Pine (Pinus sylvestris) is an excrescence consist- ing of a multitude of short shoots produced by a fungus (Perider- miurn elatinum). What is known as fasciation, or the fusing together of parts of a plant which are norm- SteP- FIG. 376. — " WITCHES BROOM " ON SCOTS PINE, Caused by the fungus Peridermium elatinum. 310 HUTCHINSON'S POPULAR BOTANY ally distinct, as in the triple flower of Fuchsia shown in fig. 377, is likewise (at least, in a large number of instances) due to gall-mites. Many of the singular metamorphoses of plant organs, too — floral leaves which are changed into foliage leaves, petals which become stamens, etc., etc. — are probably attributable to the same exciting cause — a subject of which we shall have more to say when speaking of the Flower. In some instances galls have a positive economic value, though this, of course, is of no advantage to the plant. The galls of commerce are chiefly those which occur on Quercus infectoria, and the best of them come from Aleppo and Smyrna. They yield a tine black colour with any of the salts of iron, and are largely used in the manufacture of writing- ink. Perhaps the most dreaded of gall- producing insects is the grape-louse (Phyl- loxera vastatrix), which pierces with its proboscis the young leaves and roots of the European Vine ( Vitis vinifera), and thereby causes the growths referred to. The galls, by driving away nourishment from the roots (in which they are ably assisted by the insects themselves), starve and weaken those delicate organs, and at last destroy the plant. We have now touched upon all the more important facts connected with the forms, structure, and functions of foliage leaves, and with the means provided by Nature for their protection and preserva- tion. A few remarks on the decay and fall of the leaf may fitly conclude the subject. One of the first external signs of incipient decay in green leaves is the fading of their freshness. The green becomes dull, and gradually assumes a yellow, brown, or ruddy tinge, due to varying degrees of oxida- tion of the chlorophyll, contained in the cells. The fall of the leaf is not primarily nor necessarily due to external forces. Wind and frost may, and do, perform their part, but long before the leaf has attained its full growth and vigour the busy protoplasts have been weaving a layer of cells, which shall infallibly ensure the work of disarticulation. These cells, botanically known as the layer of separation, are formed in the base of the leaf-stalk, and run at right angles to the older and displaced cells, so that they divide the leaf from its branch or stem. FIG. 377. — FUCHSIA. Monster flower caused by fasciati fhoto by} IHenry Irving. FIG. 378. — "OAK-APPLE" (GALLS OF Dryoteras terminates). About two-thirds of the natural size. They are found in May and June on the twigs of the Oak, and the numerous larvae are embedded in the soft tissue of the green- and red-skinned " apple." 311 CHAPTER XI FLORAL FORMS AND THEIR RELATIONS -TO INSECTS To me the meanest flower that blows does bring Thoughts that do often lie too deep for tears. WORDSWORTH. S there is a good deal of ground to be covered in this chapter, we will not waste time on the threshold. Our subject is the Flower— in many respects the most important, as certainly it is the most interesting, of the subjects of which Botany treats. The Flower contains the organs of reproduction, a fact which accounts for its pre-eminent importance : while the manner in which those organs discharge their appointed functions — assisted often by the most unlikely agencies, as water, wind, and insects — gives to the study of the Flower an attractiveness all its own. Root, stem, and leaf are not with- out their fascinations, too, as we have sought to show in earlier chapters, but the Flower is the part of the plant which rightfully commands the lion's share of interest. As with the leaf, the beginning of the Flower is the bud. Flower-buds originate in much the same way as leaf-buds, and cannot be distinguished from the latter in their earlier stage. Like leaf-buds, too, they are formed either in the axils or at the ends of branches, and in accordance with those conditions are named respec- tively axillary and terminal. The reader will probably recognize the little flower shown in fig. 379. It is the Moneywort or Creeping Loosestrife (Lysi- machia nummularia), an English wild- flower partial to ruins and damp woods, and a favourite rockery plant under culti- vation. It, and its near relation, the Wood- 312 FIG. 379. — CREEPING LOOSESTRIFE. An example of solitary and axillary flowers. FLORAL FORMS AND THEIR RELATIONS TO INSECTS 313 land Loosestrife or Yellow Pimpernel, offer familiar examples of a solitary and axillary flower. The Herb-paris (P. quadrifolia, fig. 381) bears solitary flowers, too, but they are ter- minal, not axillary. The Herb-paris is one of the most singular of our wild-flowers, and, like the Loosestrifes, delights in moist and shady woods. But solitary flowers, whether axillary or ter- minal, are the exception rather than the rule. In by far the greater number of plants the bud unfoldsinto a branch system, consisting of several flowers, which are known collectively as the inflorescence. The Cowslip ('Primula veris], Cherry (Prunus cerasus\ and Forget-me-not (Myo- sotis palustris) may serve as examples. What is popularly known as the "flower" of the Daisy (Bellis perennis) and Dandelion (Taraxacum officinale) is likewise an inflorescence ; each of the so-called flowers being really a multitude of minute flowers (flords] crowde'd together on a single stem. We will consider the structure of one of these composite flowers later on. In describing a flower the presence or absence of a stalk should always be noted. Stalkless or sessile flowers are comparatively rare, but the flower- stems of stalked or pedicellate flowers may be so short as to be hardly •perceptible. No more remarkable instance of a sessile flower could be named than that vegetable wonder, Rafflesia arnoldi, of which some account Photo by] [E. Step FIG. 380. — CUCKOO-PINT (Arum maculatum). The front part of the spathe has been cut away to show the minute flowers around the base of the spadix. 314 HUTCHINSON'S POPULAR BOTANY was given in a former chapter ; and if we place side by side with Rafflesia the stalked inflorescence of the celebrated Lilium giganteum, we have a contrast indeed. A flower-stem of one of these Lilies, cut from a living plant in the Sunningdale Nursery in July, 1879, is preserved in No. 1 Museum at Kew. The circumference of the pedicel is eleven and a half inches, its height thirteen feet ! Truly a Brobdingnagian flower-stem. A stalk which supports a solitary flower, or the primary stalk of an inflorescence, is called a peduncle ; while the branches or secondary stalks are known as pedicels. The stalk of Herb-paris, one of the flowers that we were looking at a moment ago, is an example of a peduncle ; so is the primary stalk of the Lily of the Valley (Convallaria majalis), while its slender branches, curving with the weight of the dainty little bells, are pedicels. The portion of the floral stem (peduncle) which, in this plant, bears the stalked flowers, is the rachis. Rachis is the Greek word for u spine," and besides being the term used in anatomical science for the vertebral column of animals, is used for many things which suggest a resemblance to the spine, as the shaft of a feather, the stalk of the frond in Ferns, the axis of a compound leaf, and (as we have just seen) the axis of an inflorescence. The Lily of the Valley is an ex- tremely useful plant for an object- lesson. Who is not familiar with its pensile beauty ? It is a favourite FlG 381 HERB-PARIS flower under cultivation, and one of Solitary and terminal flower. the ITlOSt SOUgllt af ter of wild-flowers. The plant needs some seeking, too, for it loves to hide from sight in shady glens, covering its nodding white bells with its large and glossy leaves. You perceive that the leafless peduncle springs directly from a sub- terranean stem or root-stock — a rhizome, to use the botanical term. On this account the inflorescence is called a scape, and the plant itself a scapigerous herb. The Primrose, Cowslip, and Oxlip (Primula vulgaris, P. veris, and P. elatior) also offer familiar examples of scapigerous herbs. Notice, further, that the pedicels of the Lily of the Valley spring from the axils of what appear to be minute leaves — a fact of importance, as similar leaf-like forms are found on most branched inflorescences. They are called bracts, from the Latin bractea, a thin plate of metal. Bracts are usually green, but in certain plants— as the Flowering Dogwood (Cornus jiorida] and the celebrated Edelweiss (Leontopodium alpinum) — they are white or coloured like the petals of flowers, and are then called petcdoid. In Poinsettia IE. Step. FIG. 382. — COWSLIP (Primula veris). A familiar plant whose nodding yellow flowers are borne in an umbel on a tall scape, hence it is described as a scapigerous herb. EUROPE, w. ASIA, N. AFRICA. 315 316 HUTCHINSON'S POPULAR BOTANY they form the most showy portion of the inflorescence, theflowers themselves being- small and inconspicuous. The names bracteate and ebracteate are applied to flowers according as they possess or do not possess these modified leaves. Here is a flower that will be readily recognized (fig. 380). No lover of green lanes and sunny meadows bordering banks can be a stranger to the Cuckoo-pint or Wake Robin (Arum, maculatum), with its " ear-like spindling flowers," as Clare calls them, " betinged with yellowish, white, or purplish hue." But let us be clear as to what we are looking at. The figure does not represent a single flower, but an inflorescence, the numerous flowers of which are congregated round the narrow lower part of the club- like column or spcul.ix, while the sometimes spotted enveloping case is simply a special kind of bract, known as a spathe. Any large spadix-ensheathing bract, indeed, is termed a spathe, and such leaves are quite distinct from the foliage leaves both in form and functions. The spathe of Amorphallus titrmum, an Aroid of Western Sumatra, measures nearly six feet in diameter, while its purple spadix attains a height of nearly six feet, and a single leaf has been known to cover an area of forty-five feet in circumference (fig. 384). In a large number of plants the bracts are collected in a whorl around a cluster of flowers, and then we have what is called an involucre. Such an arrangement is often of great service to the densely packed florets, particularly during the night, when loss of heat by radiation is largely prevented by the closing of the involucres. The Yellow Goatsbeard (Tragopogon pratensis) and Dandelion (Taraxcicum officinale) may serve for illustration (fig. 386). Could any more perfect arrangement have been devised for protecting their clustering florets from sudden changes of temperature than these circles of stout little bracts ? The Wood-anemone (A. nemorosa), whose white or delicate crimson petals open in April or May, has a whorl of three leaf-like involucral bracts at some distance below its FIG. 383. — OAT (Avena saliva), With branc.hed inflorescence (panicle). To the ri?ht is a single spikelet ilarsred, showing the parts more clearly. detached and FLOEAL FORMS AND THEIR RELATIONS TO INSECTS 317 single flowers. In the Limes (Tilia) the long bracts remain on the trees till the fruit is ripe, and fall with it (fig. 341). They serve the purpose of wings, and materially assist the wind in dispersing the seed. Whether the curious accrescent bracts of Neuropeltis racemosa, an Indian plant belonging to the Bindweed family (Convolvulacese), subserve a similar purpose, we are not in a position to say. In the Grasses the outer scales of the spikelets are called glumes, the inner pales or palece. One of our common cereals may be taken as an example. Here (fig. 383) is a branched inflorescence or panicle of the Common Oat (Avena saliva], consisting of a pe- duncle and pedicels, with a flower-containing spikelet at the end of each. To the right of the panicle one of the spikelets is shown separately, on a larger scale, the glumes are the outer scales, while the inner scales are the pales. The long bristle-like appendage with which one of these inner /" scales is furnished is known £_ as the beard or awn. All inflorescences resolve themselves naturally into two great divisions. When, as in the Pink (Dianthus), Buttercup (Ranunculus], Gentian (Gentiana), etc., a single flower ends the prim- ary axis, which is thereby arrested in its growth and does not elongate, fresh flowers being produced from separate axes and expanding after the central flower, then we have what is known as a definite inflorescence. When, 011 the Other hand, FlG- 384.— GIANT ARUM (Amorphallus titanum). The enclosing spathe is nearly six feet across, whilst the central spadix are produced is six feet high. Its leaves are sometimes forty-five feet in circumference. 318 HUTCHINSON'S POPULAR BOTANY laterally on the axis, which elongates and continues to produce flowers in regular succession from below upwards — as is the case, for instancer in the Snapdragon (Antirrhinum} and Wallflower (Gheiranthus cheiri], then the inflorescence is said to be indefinite. Figs. 396 and 401 will illustrate the differences : figs. 385 and 396 represent definite inflorescences, the latter with numerous floral axes ; the inflorescence of Dicentm (fig. 387) is indefinite. There is no need to give a detailed account of the various kinds of inflorescence. They are pretty numerous, and have received names which Dominie Sampson would have loved to roll off his tongue. Under the head ^ of definite inflorescences we have the fascicle, the glomerulus, the verticillaster, and five kinds of cyme — spiked, panicled, corymbose, dichotomovs, and Jfj^^ scorpioid ; while the nomenclature of the various ^J^C. '^^•j forms of indefinite inflorescence is even more extensive. Those with lengthened axes and sessile flowers, which form a sub-group under the common name of spikes, comprise the catkin, spadix, strobile, and cone ; those with lengthened axes and stalked flowers, constituting a second sub-group under the name of racem.es, comprise the corymb, panicle, and thyrsus. Then there are the forms with shortened axes and sessile flowers, the anthodium and hypanthodium, which may be bracketed under capitula to make a third group ; and, lastly, we have the two kinds of umbel, simple and compound, both characterized by shortened axes and stalked flowers. They may be tabulated thus, and the illustrations will help the memory : FIG. 385. — PINK. An example of definite inflorescence. DEFINITE INFLORESCENCES INDEFINITE INFLORESCENCES (page 327). (page 331). Fascicle (c) Spikes. Racemes. (Sessile flowers on lengthened axes.) (Stalked flowers on lensthened axes.) Glomerulus (e) Catkin (h) Corymb (i) Spadix Panicle (e) Verticillaster (/) Strobile (c) Thyrsus (/) 'Spiked Cone (a) Panicled (a) Cyme- Corymbose (b} Capitula. Umbels. Dichotomous Anthodium ( Wherei the ,definite aCt °f lm- Section showing receptacle (r) to which the carpels pregnatlOn takes place. (cp) are attached. They form collectively the pistil, T, . , and, when ripe, the fruit. ' It is important to get a clear grasp FIG. 390.— SECTION THROUGH PISTIL OF SNAPDRAGON. Ovary (a) ; style (b) ; 'stigma (c). \Henry Troth. FIG. 392. — AMERICAN MEADOWSWEET (Spircea salicifolia). A favourite plant of pollen-seeking insects, with thyrsoid inflorescence. NORTH AMERICA. ASIA. 323 324 HUTCHINSON'S POPULAR BOTANY FIG. 393. — ABNORMAL FLOWER OF Wistaria, With two petaloid stamens (/«.). (The keel, wings, and standard have been removed.) of what has been before us in this rapid sketch. The process that has been described is the same, in all essential particulars, as that which goes on in the great majority of flowering plants, and it is so simple as to be easily understood. The pollen may be conveyed to the stigma by other than insect agency, and the tubes may pursue a more winding course through the conducting tissue ; but these are details, and the above descrip- tion may be accepted as a fairly representative one. What actu- ally takes place in the ovules when the pollen-tubes have found an entrance will be explained farther on (Chap. XIV.) ; it is sufficient here to have directed attention to the fact itself. The growth of the tubes may be conveniently demon- strated with the pollen of the cultivated varieties of Caladium, all that is needed being to leave a few grains on a damp microscope slide for five or six hours. We have already seen that the beginning of the flower is, like the beginning of the leaf, the bud ; and that a flower-bud and a foliage-bud are indistinguishable in the early stages of growth. The theory of the develop- ment of all parts of the flower from leaves was enunciated by the poet Goethe nearly a century ago ; and though the announcement of his discovery was accompanied by a good deal of speculation which subsequent research has shown to be erroneous, his main position had much to recommend it. nor does it lack defenders even at the present day. Goethe taught that " the elementary floret expands into a leaf upon the stem, contracts to make the calyx, expands again to make the petal, to contract again FIG. 394. — ABNORMAL FLOWER OF Begonia, into sexual organs, and expand for With sepals developed a? green foliage leaves. the last time illtO fruit.". FLORAL FORMS AND THEIR RELATIONS TO INSECTS 325 On the other hand, there are physiologists of the first rank who hold the theory of the German poet in light esteem, and to whom the pronounce- ment that " every flower is simply a metamorphosed leaf-shoot " is a dangerous expression, implying that the flower has been developed in course of evolution from a leaf-shoot, for which, in their judgment, there is not sufficient evidence. We are disposed to concur in this view, and rather than yield allegiance too readily to Goethe's theory would say Photo &y] [E. Step. FIG. 395. — LARGE-FLOWERED ST. JOHN'S WORT (Hypericum calycinum). Also known as Rose of Sharon. The large flowers offer good examples of spiral aestivation. The profuse stamens form a number of little bundles. that there are flower-shoots and leaf-shoots, without attempting to derive one from the other. Yet the tendency of the floral organs to relapse into the foliar form in certain abnormally developed flowers, at least confirms the idea that floral leaves and foliage leaves are homologous structures. Most of us, doubtless, have met with flowers of the kind referred to — " monstrous " flowers, as they are called. In Science Gossip (1890) there is an interesting series of papers on the subject, by Dr. J. E. Taylor, with drawings of some of the more remarkable monstrosities. In one place we find an abnormal Knapweed (Gentaurea nigrci), of which some of the florets have become leaf-like; in another, a Daisy (Bellis perennis} has 326 HUTCHINSON'S POPULAR BOTANY developed a true foliage leaf instead of a bract in the involucre. A third specimen (a flower of the Enchanter's Nightshade — Circcea lutetiana) appears with a portion of its stigma transformed into the anther of a stamen, and a stamen assuming the character of a pstal, while, in place of another of its petals, two sepals are developed ! Not less remarkable is the figure of a Peach-flower, whose organs exhibit a stead}r gradation from petals to foliage leaves ; and farther on in the volume we meet with an abnormal Rose, entirely devoid of petals, and with sepals which seem to have been trying ard to produce a serrated margin. The stamens of this flower are normally developed, but the pistil (if pistil it may be called) is a curiosity, the style being elongated into a green and healthy-looking shoot, bearing some two or three dozen ordin- ary leaves ! The " monster " flowers which have come under our own notice are not so singular as those figured in Dr. Taylor's remarkable articles, but they serve no less to illustrate Goethe's law. The first figure (fig. 393) repre- sents a flower of Wistaria, from which the coloured petals have been removed. In this example the abnormally de- veloped organs are the stamens, one of which has a small leaf-shaped purple petal growing out from the centre of the style ; while another has developed a similar petaloid organ in place of the anther-lobes. In the second figure (fig. 394) we have a "monstrous" flower of Begonia (B. octavia], whose outer petals — or rather sepals — have been metamor- phosed into green leaves, with midrib, veins, etc. In many species of the genus Clematis, the sepals are petaloid — that is to say, they are coloured like true petals, while the petals are absent. The former are spoken of collectively as the perianth, this being the name applied to the floral envelopes of a flower when calyx and corolla are not easily distinguished. It would be well, perhaps, to keep exclusively to this use of the term, rather than apply it in a loose way to the floral envelopes of any and every flower. In the figure of Clematis ccerulea (fig. 398), the six petal-like organs (really sepals) constitute the perianth. Probably no flower better illustrates the truth we are considering than FIG. 396. — SNAPDRAGON. A portion of the stigma and style, showing pollen- grains on the former putting forth tubes and pene- trating the style. FIG. 397. — DEFINITE INFLORESCENCES. 327 328 HUTCHINSON'S POPULAR BOTANY the "White Water-lily (Nymphwa alba), in which the gradual stages of transformation from, the green sepals of the calyx to the yellow pollen- producing stamens may be seen to great advantage. We are not speaking now of " monstrous " specimens of the flower (nor were the Begonia and Clematis last alluded to at all abnormal), but of the ordinary White Water- lily ; which thus shows, in a permanent fashion, the community which exists between the various members of the flower. For the sepals merge into petals, and the petals into stamens, by such imperceptible gradations that at certain points it is difficult to say to what set Q£ organs particular parts belong. In drawings made to illustrate the fact, it is easy enough to see that one figure with its dark green colouring is a sepal, and that a second, though of a paler green, is probably a sepal too; but what of the next figure ? This is neither a decided green nor a pure white, but a cross between the two, and it might be called in- differently a sepal or a petal. In the next row we have petals beyond a doubt; but we are again at a loss when we come to another row. Do these organs repre- sent petals or stamens ? They are broad and white like the former row, but the thickening at their apex is of a yellow colour, and has all the appearance of rudimentary anther- lobes. The figure beside it is equally perplexing, and not till we get far in do we find a stamen pure and simple, with normally developed style and anther and abundance of pollen. The transition is far more gradual than the description might lead one to suppose. In the flower itself a large number of petaloid sepals and stameniferous petals have place between the organs named ; and each differs in some slight degree from its neighbour. Here, then, you have an abiding witness to the facts of which we have been treating — a constantly accessible illustration of that homology of structure which seems to exist between the members of every flower. We are now in a position to carry our inquiry a step farther. A flower being only a modified shoot, it is not surprising that the FIG. 3. — FLOWER OF Clematis ccerulea, With petaloid sepals. FLORAL FOEMS AND THEIR RELATIONS TO INSECTS 329 / FIG. 399. — ^ESTIVATION OF FLOWERS. (a) Valvate. (6) Imbricate, (c) Contorted or twisted. ( uguiate corona. 330 HUTCHINSON'S POPULAR BOTANY We approach more interesting ground when we begin to speak of the expanded flower. The question of form and arrangement again meets us on the threshold, but the study of the structural variations of flowers by 110 means confines one to the acquisition of name -lists or to tedious and meagre definitions. The question is one of scientific importance, involving as a preliminary step the arrangement of multitudes of appearances under primary points of view, and their classification according to rule and exception ; by which means alone a discovery of the actual laws of Nature is rendered possible. Now, manifold as are the structural arrangements of flowers, the variations really concern only a few simple subjects, and when these are grasped the investigation of the causes which produce the differences in the whole floral world is by no means a hopeless under- taking (Schleiden). The subjects of variation are, in fact, four; and the first to be mentioned is number. A Lily, for example, has three sepals, three petals, and six (i.e. twice three) stamens ; while its pistil, though looking like a single organ, is really made up of three carpels which have grown together. The Lily belongs to the great class of Monocotyledons, and three may be said to be the characteristic number of that class. In the floral whorls of Dicotyledons, on the other hand, threes are a rarity ; nor can any number be said to be charac- teristic, though fours and fives are very common. A Fuchsia has four coloured sepals, four petals, twice four (i.e. eight) stamens, and four carpels. A flower of Cherry, on the other hand, has its two outer whorls, the calyx and corolla, in fives, and its stamens form a multiple of five — namely, twenty. The ovary does not follow the rule — it is solitary ; nor is this case by any means an exceptional one, the parts of the pistil in the majority of Dicotyledons being fewer than in the other whorls. It might easily be shown that whorls of flowers correspond to cycles of leaves, but it would be exceeding our present limits to push our inquiries farther in this direction. The second of the four subjects of variation is cohesion. This term is applied by botanists to the union of like parts in a flower, as of sepal with sepal, petal with petal, stamen with stamen, and so forth. Both the calyx and corolla of a Primrose are good examples of cohesion. Here the five sepals unite in a tube and form what is called a gamosepalous calyx ; the five petals are also fused together, and so the corolla is described as gamopetalous.- A calyx whose sepals are not united is said to be polyseptdous ; a corolla with separate petals is polypetcdous. In the Laburnum (L. vulgare) the fila- Fia. 401. — COMMON PEA. A carpel with seeds removed. FIG. 402. — INDEFINITE INFLORESCENCES. tdits Iupulits1. of Horse chestnut (.Esculus (a) Cone of Larch (Larix europea). (ft) Umbel of Cowslip (Primula veris). (c) Strobile of Hop (H (d) Hypanthodium of Vis (Ficus carica). (e) Panicle of a Yucci. (/) Thyrsus of Horse ch kippocajstanum). (g) Capitulum of Corn Blue-bottle (Centaurea cyanus). (A) Catkin of Hazel (Corylus avellana). (0 Corymb of Cherry (Cerasus mahaleb). (k) Compound umbel of Fool's Parsley (.f.thusa cynapium). 331 332 HUTCHINSON'S POPULAR BOTANY - FIG. 403. — CARROT (Daucus carota). Section through epigynous flower. ments of the stamens cohere so as to form a tube — they are monadel- phous. In the Dandelion (Taraxa- cum officinale) it is the anthers which unite, and the stamens are said to be syngenesious (fig. 400). Lobelia shows both conditions. Stamens which are united into two, three, or more groups are termed cZi-, tri-, and poly- adelphous respectively. Then as to carpels. These may be united in two ways. " If we take a pea-pod, we shall find that it closely resembles a narrow, long- pointed leaf folded down the middle, with the edges in contact. Such is really Nature's method of making a carpel, of course greatly modifying the leaf for its new purpose (fig. 401). The peas, i.e. the ovules, are always produced down the united margins in two rows, i.e. one row on each margin. Now suppose we take two or more pea-pods. Place them with their margins in contact, and then compress them so that the sides will meet, and imagine them to have thus grown in contact. They would then be in a state of cohesion, and a cross section through the ovaries would reveal as many chambers as there are carpels. That is one way. This is well seen in the pistil of the Bluebell (Scilla nutans) [and the Purple Spring Crocus (Crocus officinalis^ fig. 406j]. Another may be illustrated as follows : Take two or more pods, but this time crack them open down the margins where the peas are (but not down the opposite side) ; half the peas will now be found on one margin and half on the other. Now place the open pods in a circle, edge to edge, and imagine the edges only to become coherent. There will thus be one large chamber, with as many double rows of ovules as there are carpels. The Violet (Viola) and Mignonette (Reseda lutea) will illustrate this condition " (Hen slow). Pistils which are made up of two or more carpels are de- scribed as compound, to dis- tinguish them from simple pistils, which contain only one FIG. 404.— BEGONIA. Carpel. Yet it mUSt not be Section across syncarpous ovary, showing axial plaeentation. FLORAL FORMS AND THEIR RELATIONS TO INSECTS 333 supposed that the carpels of all compound pistils cohere. In the Buttercup, for example, they are free and distinct (fig. 407), whence they are called apocarpous. In Begonia, on the other hand (fig. 404), they are united, or syncarpous. We come now to the third subject of variation — namely, adhesion, or the union of imlike parts of a flower. A calyx uniting with a corolla, a corolla with stamens, and stamens with pistil, would all be instances of adhesion ; though the first-named manner of union is not common. Very seldom do FIG. 405. — DOG-ROSE AND FIELD-ROSE. Showing urn-shaped (iirceolatK) receptacles, which later turn red and become the " hips The calyx is seen above the receptacle. enclosing the fruits. sepals unite with petals — or, indeed, with members of any other floral whorl. The adhesion of petals and stamens is, however, common enough, and ma}- be looked for as a thing of course ivhenever the petals of a floiver cohere* A well-known example is the Foxglove (Digitalis). On opening one of the flowers the four stamens may be seen adhering to the inner side of the bell- shaped gamopetalous corolla. The anther-lobes and a part of each of the filaments are free, but the lower portions are united to the corolla, upon * Flowers of the Heath family (Ericaceae} are among the few exceptions. 334 HUTCHINSON'S POPULAR BOTANY which they appear as prominent ridges. Adhesion between stamen (or stamens) and pistil is comparatively rare, but MUj^j when this consolidation of male with female organs takes jf^ji place they are called gynandrous, from the Greek gune, a female, and andros, male. The fourth and last subject of variation is form. The old idea that the beautiful and oftentimes singular shapes FIG. 406. — of flowers were designed by the Creator chiefly — if not ex- CROCUS. clusively — for the pleasure of man has been long discarded Transverse section " . . of ovary showing by thought! ul minds ; and in the present day one hardly chambers. needs to be told that the manifold varieties of floral form are, in the vast majority of cases, so many adaptations for the admission or exclusion of insect visitors, and for facilitating the disper- sion of the pollen. In the zest of what is still, in effect, but a new discovery, many facts relating to this subject have doubtless been distorted, and theories built upon them which will have to be modified or withdrawn ; yet the great central fact remains, and it is one of wide-reaching importance. In succeeding chapters some account will be given of the peculiar contriv- ances by means of which insects are lured to certain flowers and are made the unconscious instruments of pollination ; but at present it is better to direct our attention to typical rather than to special forms. It should be further remarked that the subject of Form has particular, though by no means exclusive, reference to the calyx and corolla. Many uses have been enumerated for these floral envelopes. In the earlier stages of the flower they serve as a protection to the delicate cells of the immature stamens and pistil; and at a later period they perform the same kindly offices for the pollen, which might otherwise be blown away prematurely by the wind, or be stolen by unbidden insect guests, or rendered abortive in consequence of injuries from rain and dew. In many plants, again, they assist in bringing about autogamy— that is, the fecundation of the flower by its own pollen ; while in others, their powerful odours and vivid colours, by attracting pollen-dusted insects, are instrumental in effecting a precisely opposite result — namely, allogamy or fecundation by pollen from another flower. Lastly, the floral envelopes may act as a protec- tion to the nectar, which, though oftenest secreted at the base of those organs, is not infrequently found in hollows and warty projections of the stamens and pistil. Beginning with the outermost floral whorl or calyx, tlet us try to realize, by means of a few examples drawn from familiar flowers, some of the facts to which we have been referring. We can conceive of no easier or more interesting way of acquiring a knowledge of the mor- BuTTERcup phology of floral organs than by considering them in Apocarpous fruits. relation to the functions which they fulfil. FIG. 408. — GARDEN CLEMATIS (Clematis jackmanni). A climbing plant of the great Buttercup order, with no distinction between sepals and petals. 336 HUTCHINSON'S POPULAE BOTANY In some flowers — as the Carrot (Daucus carota, fig. 403) — the calyx is a quite inconsiderable set of organs ; while in others, as the Alpine Liane (Atragene alpina), Delphinium consolida, the Hellebores (Helleborus), and the curious Molucella, it forms the most attractive part of the flower. This is notably the case with the shallow bell-shaped calyxes of the last-named flower, to which is due the very singular appearance of the densely packed axillary flowers, arranged in whorls on the stems. Delphinium has its posterior sepal prolonged as a spur, into which the two petals (or, rather, gamopetalous corolla), which are also spurred, fit as neatly as a lady's finger in a glove. Now in this flower the petaloid spur is the nectary, so that the ensheathing sepal of the calyx is simply a beautiful arrangement for the protec- tion of the nectar. The Garden Nasturtium (Tropceo- lum majus) is also furnished with a spurred calyx, but the corolla has no such ap- pendage ; nor is one required, for, in this instance, the sepa- line spur is itself the nectary (figs. 410 and 411). In the Monkshood (Aconi- tum) we have an example of a helmet-shaped or galeate calyx (fig. 409). The two posterior sepals unite to form the helmet ; and the structure, which reminds one of the head-armour of some Homeric hero, affords excellent pro- tection to the anthers and FIG. 409. — MONKSHOOD (Aconitum napellus). nectaries. The two lateral Humble-bee entering helmet-shaped (galeate) flower. Sepals are Serviceable ill another way, as they form a platform for humble-bees, which play an important part in the pollination of the flower. The urn-shaped or urceolate floral receptacle of the Rose (Rosa) — that green shiny swelling which afterwards changes to a red colour and forms the outer covering of the berry — is often spoken of as the calyx ; but it is more correct to restrict this term to the five segments which spring from the somewhat contracted margin of the urn, and which, in such cases, are simply free sepals (fig. 405). As these sepals remain after the fruit has ripened, the calyx is said to be persistent — a feature which the Eose possesses in common with the Henbane (Hyoscyamus niger, fig. 412), Mallow (Malva], Pear (Pyrus FLORAL FORMS AND THEIR RELATIONS TO INSECTS 337 FIG. 410. — NASTURTIUM. Section through flower, showing interior of calyx spur. communis), Apple (Pyrus mains), Goose- berry (Ribes grossularia), Strawberry (Fragaria vescci), and Melon (Gucurbita). In other flowers, however — the Butter- cup (Ranunculus) will serve as an ex- ample— the calyx is deciduous, that is to say, it falls off before the fruit ripens ; while in a few cases, as the Poppy (Papaver), Eschscholtzia, and those inter- esting Malayan shrubs, the Pternandras (fig. 413), where its chief purpose appears to be to protect the young and insecurely fastened petals of the bud, it drops off as soon as the flower opens. Such a calyx is said to be caducous. Some per- sistent calyxes are accrescent — that is, they continue to grow after the flower- ing time, like that of the "Winter Cherry (Physalis alkekengi), a solanaceous plant often cultivated in gardens. The highly coloured inflated calyx of this plant is, indeed, its sole attraction, for the cohering sepals so enclose the other organs of the flower as to hide them completely from view (fig. 417). We mentioned the Strawberry just now, and we may add that the calyx consists (apparently) of a double whorl of sepals — in other words, of two calyxes * — and some botanists distinguish them by call- ing the outer whorl the epi-calyx. Whatever may be the general pur- pose of an epi-calyx, it certainly renders good service in the case of the Strawberry by protecting the young "fruit" from the depredations of insects — not of winged insects, of course, but of those which approach the coveted object by way of the stalk. * Another opinion is that there is only one whorl of sepals, the outer structures being regarded merely as stipular growths thereupon. II— 4 FIG. 411. — NASTURTIUM (Tropceolum majus), With spurred calyx. 338 HUTCHINSON'S POPULAE BOTANY FIG. 412. — HENBANE. Urceolate persistent calyx. Against winged insects a more or less inflated calyx is often a first-rate protection ; for besides putting them to the labour of gnawing through the calyx before the proboscis can be inserted, it serves to hold them at a distance even when that difficulty has been surmounted. Take, for in- stance, the sack-shaped (saccate) base of the calyx of Honesty (Lunaria, fig. 415), and con- ceive how difficult it would be for one of the smaller tissue-gnawing insects to get at the in- terior of the flower. To bite a hole large enough for the insertion of its proboscis would not be sufficient ; the hole would have to be widened till it was large enough to admit the insect itself, otherwise the little plunderer would be too far off to reach the nectar. In flowers where the inflation of the calyx is greater, the difficulties of gaining access to the interior are, of course, proportionately increased. We must not stop to particularize, though the globose calyx of the "Winter Cherry, to which we referred a moment or two ago, would afford a ready illustration. The whole subject will be before us again in the next chapter, when we shall deal with the contrivances in flowers for the exclusion of unbidden guests, one of the most fascinating of botanical themes. The other forms of calyx which remain to be spoken of may be treated in connection with the forms of the corolla, to which we now invite attention. Let us commence with a perfectly symmetrical or regular flower — that is to say, one the halves of which, produced by all possible sections, are similar ; such, for example, as the Wallflower (Cheiranthiis ckeiri). Here we have a calyx of four sepals, two overlapping the edges of the other two so as to form a sort of false tube (a true tubular calyx may be seen in the Primrose — Primula vulgaris), and these serve as a support to the four clawed petals, which, it will be noted, are arranged in the form of a Maltese cross. Hence, the corolla is described as cruciform. It would be going too far from our subject to show how the several correlated points of structure in this flower are connected with its pollination by insect agency ; but we may just notice how admirably the cruciate corolla is adapted as a landing-stage for nectar-seeking visitors. FIG. 413. — Pternandra cordata. Flower-bud showing (p) petals, (c) calyx, (r~) receptacle. FIG. 414. — GARDEN LARKSPUR (Delphinium exaltatum). A beautiful North American plant much grown in gardens, where crossing and selection have produced many varieties. The showiness of the flower is due to the sepals, the petals being reduced to two small nectaries, the dark centre of the flower in the photograph. 339 340 HUTCHINSON'S POPULAR BOTANY FIG. 415. — HONESTY (Lunaria). Section of flower showing saccate calyx. In contrast to the Wallflower, take a Pansy ( Viola}. A Pansy is a good example of an irregular flower. By cutting through the centre perpen- dicularly we get two similar halves, but in no other way can the flower be divided symmetric- ally. Flowers exhibiting this kind of bilateral symmetry are known as monosymmetrical or zygo- morphic (Greek zeugnumi, I join, and morphe, a shape). Flowers the petals '"'of which are placed like the spokes of a wheel, and which may there- fore be divided vertically into similar halves through two or more planes, are termed actinomor- phic (Greek aktin, a spurious form of aktis, a ray, and morphe). All regular flowers are actinomor- pliic : most irregular flowers are zygomorphic. Some flowers cannot be symmetrically divided in any plane— they are asymmetric. There is a curious fact about the Pansy. What appears to be the lower- most petal is really the upper, for the flower has been reversed. It has been thought that the purpose of the curve in the flower-stalk is to strengthen the flower and thus to enable it to sustain the weight of insects. When a honey-bee visits a Pansy, it almost always turns round on alighting, and sucks with its head downwards, and the flower is bent down by the insect's weight — a circumstance which indirectly bears out this idea. Notice the streaks of colour on the petals, all leading towards the centre of the flower. They are honey-guides for the insect visitors — pathfinders, as some have named them. There will be more to say about these pathfinders on a future occasion, but allusion is made to them here by way of emphasizing the contrast which the petals of this flower present to those of another common flower, the White Cam- pion (Lychnis vespertina, fig. 416). The pure white corolla of this species of Campion has no guiding marks ; in this case they would be of no service, for the flower expands in the evening, and insects are attracted to it by its whiteness. There are five petals, attached by claws to the base of a tubular calyx, and these are the characteristic fea- tures of a caryophyllaceous corolla. The Maiden Pink (Dianthus deltoides), Carnation (D. caryophyl- lus), and Catchfly (Silene) exhibit the same features. The rosaceous corolla consists of five petals, too, but they are without claws : the Buttercup (Ra- nunculus, fig. 419) is a good example. FIG. 416. — WHITE CAMPION (Lychnis vespertina), With styles exserted. FLORAL FORMS AND THEIR RELATIONS TO INSECTS 341 417. — WINTER CHERRY (Physalis), Showing the accrescent calyx. Notice how the corolla of the White Cam- pion is constricted near its upper end by the toothed or dentate calyx. This is another con- trivance for shutting out unwelcome visitors. Only a thin proboscis, at least three-fifths of an inch long (such, for instance, as that of the Small Elephant Hawk-moth (Chcerocampa porcellus), which often visits and cross-pollinates the flower), could reach to the fleshy part of the ovary where the honey is stored. In fact, both the calyx- tube and the elongated claws of the petals assist in preserving the nectar for those insects whose visits are really serviceable to the plant. In flowers with salver-shaped (kypocrateriform) corollas, like the Primrose and Common Lilac (Syringa vulgaris), the tubes formed by the cohering petals answer much the same purpose as the clawed bases of caryophyllaceous corollas, and also protect the pollen from drops of rain and dew — the latter an important consideration in the case of plants which dwell amid mountain-mists, like the delicate species of Primulacese belonging to the genus Androsace, and many species of Phlox (fig. 421). " If flowers of Aretia glacialis, a plant growing on the moraines of glaciers, are examined after a shower," says Kerner, "it is found that every one has a drop resting upon it which slightly compresses the air in the narrow tube of the corolla, but cannot reach the pollen upon the anthers lower down the "tube. A subsequent shake or puff of wind causes the drops to roll off the limb of the corolla, or else they are got rid of by evapora- tion ; in either case, the flower becomes once more accessible to insects." Salver-shaped corollas must be distinguished from rotate or wheel- shaped corollas, such as we get, for instance, in purple-flowered "Woody Nightshade (Solatium dulcamara). In the former the tubes are long and narrow, in the latter they are short ; but in both the limb is placed at right angles to the tube. We come now to the tubular corolla. From what has been said about the uses of caryophyl- laceous and salver-shaped corollas, the purpose of this third form may be readily divined. It, also, has reference to insect-pollination. The Com- , , . T . FIG. 418. — GREAT VALERIAN moil Honeysuckle (Lomcera perydymenum) may (Valeria™ officinalis). serve as an example. The sweet-scented flowers showing the gibbous oc-roua. 342 HUTCHINSON'S POPULAR BOTANY are adapted for fertilization exclusively by long-tongued crepuscular and nocturnal moths : and why ? Because the wax-like tubes are long and narrow — too long for short-tongued insects to reach the honey while standing at the mouth of the flower, and too narrow to enable them to descend bodily to the nectary. As a matter of fact, the flowers bloom at the very season when hawk-moths are most abundant — that is, during May and June — and they exhale their perfume most strongly in the evening, when these moths are on the wing. Another form of gamopetalous corolla which must not be passed over is that which, from its resemblance to a funnel, has received the name infundibuliform. The name is less elegant than the flower to which it is applied. The delicate white chalices of our beautiful Hedge Convolvulus (G. aepium) are of this form. Funnel-shaped flowers have not such a reputation for exclusiveness as have those of tubular and salver shape ; and it has been observed of the Hedge Convolvulus that all sorts of thrips and little flies frequent the flowers by day, sheltering and feeding there, though they confer no benefit in return. Only on bright, moonlight nights, when the sphinx-moths are about, does the plant reap any advantage from its visitors. A friend of the naturalist Delpino, standing by a hedge overgrown with this Bindweed, was able to capture numbers of one species of sphinx-moth (S. convolvuli] simply by closing with finger and thumb the orifices of the flowers as the moths inserted -their heads. A form of corolla closely related to the infundibuliform is the campanulate, or bell-shaped. We have examples of a regular campanulate flower in the Rampion (Campanula rapunculus, fig. 426) and other Bell-flowers, and of an irregular or oblique campanulate flower in the equally well-known Foxglove (Digitalis, fig. 420 j. The wide bell-shaped corollas of Campanula are specially adapted for humble-bees ; but the flowers number other kinds of bees among their visitors, and numberless beetles and small flies use them as shelters from the rain or make the comfortable bells their night quarters. The Foxglove is also specially adapted for humble-bees, for, says Hermann Miiller, " no other insects are large enough to touch the stigma and anthers with their backs when creeping into the tube." They are, in fact, the only pollinators of the Foxglove. Possibly the enlargement of the under side of the corolla, which gives the irregularity to the flower, is intended as a landing-stage for the insect (it is certainly so used), and may also be an arrangement FIG. 419. — ROSACEOUS COROLLA OF A BUTTERCUP. FIG. 420. — FOXGLOVE (Digitalis purpurea), With obliquely bell-shaped corollas which can be pollinated only by humble-bees, for which they have become specially adapted. The lip on the lower side forms an alighting platform from wtiich the humble-bee crania right into the bell. WESTERN EUROPE. 343 344 HUTCHINSON'S POPULAR BOTANY FIG. 421. — MOSSY PINK (Phlox subulata), With salver-shaped corollas. to relieve the strain upon that part of the bell where the weight of the humble- bee presses most. We find ourselves among flowers of more intricate construction when we come to speak of labiate or lipped corollas. The White Dead-nettle (Lamium album), one of the commonest of our weeds, is the - flower chosen for illustration (fig. 425). The corolla is decidedly irregular, and on a cursory examination it is not easy to distin- guish from one another the five coher- ing petals which compose it; though by bearing in mind the simple rule that petals should alternate iviih sepals, the difficulty will vanish. Guided by this rule it will be found that the lower lip or cleft piece in front is one petal, that the pointed and inconspicuous appendages on either side the corolla- tube are the rudiments of two more, and that the remaining pair form the overshadowing hood or upper lip of the flower. "We can estimate by direct observation," says Hermann Miiller, "how perfect the adaptation of this flower is to bees' [humble- or other large bees'] visits. The bee alights on the under lip, and in doing so thrusts its head between the broad lateral lobes of the mouth, clings with its fore feet to the base of the under lip, and with its mid- and hind-feet to the two lobes of the under lip; then if its proboscis is not less than ten millimetres [about two-fifths of an inch] long, it can at once reach the base of the flower. While sucking, the thorax, and in the case of small workers the base of the abdomen also, fills up the space between the upper and lower lips, and the vaulted upper lip fits the bee's back, which is pressed against the stigma and the open face of the anther." Personate or mask-like corollas, of which the Toadflax (Linaria) and Snapdragon (Antirrhinum,) offer convenient examples, are even more elaborate in their construction than the labiate form. They re- FIG. 422. — WHORTLE- BERRY ( Vaccinium). Urceolate corolla. FIG. 423. — GRAPE- VINE (Vitis). Mitraeform corolla. FLORAL FORMS AND THEIR RELATIONS TO INSECTS 345 semble the latter in possessing a double lip, the essential point of difference being that their lower lips approximate to the upper, so as to close the orifice of the tube or throat. In the Toadflax (fig. 429) this arrangement shuts out flies and beetles, which lack the requisite strength to force an entrance, while the length of the nectar-storing spur excludes short-lipped bees, which are not so incapable of breaking in. Thus the flowers become exclusively adapted for the long-tongued species, by which, indeed, they are diligently visited. The Toadflax, it may be noted in passing, is one of those flowers which, though normally irregular, will sometimes become regular by producing in all their petals or sepals the very fea- ture which is the cause of their ir- regularity. In the flower in question, the peculiarity is that each of the five petals, by vir- tue of this excess of irregularity, pro- duces a spur, while the upper part of the flower loses its personate character and becomes regu- lar. The • wonder excited in the mind of the great Linnaeus by this phenomenon led him to apply to it the name pdoria, from the Greek word peldron, a monster. Of course, in a normally and regularly spurred corolla, like the Columbine (Aquilegia, vidgaris, fig. 427), the term " peloria " would not be applicable. The arrangement in the personate corolla of the Snapdragon is similar to that of Toadflax, though not identical. Here, as there is no spur to keep off smaller bee-intruders, the entrance is more firmly closed, and it is only when the flower is old and beginning to wither that it opens its door to such visitors. The flower is, indeed (to quote Lord Avebury), ".a strong box of which the humble-bee only has the key/' This guard- ing of the entrance is a necessary precaution, for if flies and small Photo by} [E. Step. FIG. 424. — SEASIDE CONVOLVULUS (Convolvulus soldanella), With funnel-shaped pink flowers. The leaves are small, heart-shaped or kidney- shaped, and the stem rarely twines. 346 HUTCHINSON'S POPULAR BOTANY bees were admitted from the first they would simply pilfer all the honey, and the flower would be less diligently visited by its chief pollinators, the humble-bees. Ants and small flies, however, will often squeeze their way in, their great difficulty being rather how to get out than how to gain an entrance — a circumstance referred to by Mr. Knapp in his charming Journal of a Naturalist. " It has not perhaps been generally observed," he writes, "that the flowers of this plant— ' bulldogs,' as the boys call them — are perfect insect traps ; multitudes of small creatures seek an entrance into the corolla through the closed lips, which upon a slight pressure yield a passage, attracted by the sweet liquor that is found at the base of the germen [ovary]; but when so admitted, there is no return ; the lips are closed, and all advance to them is impeded by a dense thicket of woolly matter, which invests the mouth of the lower jaw. Smooth lies the road to Pluto's gloomy shade ; But 'tis a long unconquerable pain To climb to these ethereal realms again. But the Snapdragon is more merciful than most of our insect traps. The creature receives no injur}' when in confinement ; but, having con- sumed the nectareous liquor, and finding no egress, breaks from its dungeon by gnawing a hole at the base of the tube, and returns to liberty and light." This last statement is evidently a mistake. Mr. Knapp is probably referring to the neat round hole which is made by certain short- tongued bees from without, to enable them to reach the nectar and nullify the flower's pre- cautions for their exclusion. The wood-ant (Formica rufa] is a common plunderer of the flower, but, as already re- marked, its chief pollinators are humble-bees, which do no injury to their host, and leave by the door they enter at. " It is most interesting to observe," writes Kerner, " how a humble-bee buzzes about till it alights on the two knobs of the lower lip, and then, having opened the mouth by means of hinges on either side of the corolla, suddenly disappears into the cavity of the flower to fetch honey. In the Calceolarias," continues this writer, " the phenomenon is even more remarkable. The humble-bee sits on the inflated, slipper-like lower lip, and opens the mouth by a light pressure against the upper lip. Then a nectary, hitherto hidden in the slipper-like cavity, comes to light, flap-like, and amply provided with FIG. 425. — WHITE DEAD- NETTLE (Lamium album). The two-lipped calyx is also shown separately (lower figure). Photo by] FIG. 426. — RA.MPION (Campanula rapunculus), A rare wild-flower that may be mistaken at sitfht for the Hire-hell, but the vvriijhi (lowers are borne in a panicle, instead of bein? drooping and solitary or in a few-flowered raceme. EUROPE, NORTH AFRICA, NORTH ASIA, NORTH AMERICA. 347 348 HUTCHINSON'S POPULAR BOTANY FIG. 427. — COLUMBINE (Aquilegia vulgaris), With each of the five petals ending in a spur. honey. This nectary is presented to the humble-bee just like a spoon as it sits on the lower lip. Directly the bee goes, the lower lip snaps to, and the nectary disappears from view." The Calceolarias, indeed, bring before us a new form of corolla, the calceolate, or slipper- shaped. They offer good illustra- tions of special thickenings in parts of flowers where the strain caused by insects is most felt. Calceolaria pavonii is a striking example of this. Along each of the upper edges of the curved basal part of this flower — that part which carries the inflated end upon which the bee stands— there is a thickened ridge, and this gives wonderful strength to the support and prevents injury when the bee alights. The very cohesion of the petals, in this as in all flowers where cohesion takes place, is also a source of strength ; and swellings and hollow projections in particular places may subserve a" similar end. The bulge in the tubular part of the Foxglove flower is evidently for this purpose ; as in all probability are the curious projections in many kinds of gibbous or pouched corollas. The Great Wild Valerian ( Valeriana officinalis, fig. 418) offers a good example of this form. The small pouch or hump in this particular flower is the nectary, in the green fleshy floor of which the honey is secreted. As the pouch is short and easily accessible, the flower is largely patronized by insects, and cross- mm FIG. 428. — PAPILIONACEOUS COROLLA, With the parts separated, (v) Vexillum or standard (a) Alee or wings, (c) Carina or keel. pollination regularly takes place. Returning for a moment to the simpler kinds of gamopetalous flowers, notice a familiar example of the globose corolla (fig. 430). It is the Fig wort (Scrophularia nodosa], FLORAL FOEMS AND THEIE RELATIONS TO INSECTS 349 which blooms in moist places from July to September. Perhaps it is not the best instance that might be given of the globular form — some of the Heaths (Erica) would better fulfil the requirements of the name — but we have adopted it because the flower is one of those which, unlike the flowers which we have been hitherto considering, lay them- selves out for pollination by insects with short probosces. Wasps are its chief visitors, and easily reach down to the honey at the base of the corolla : while long-tongued insects, such as humble-bees and butterflies, avoid the flower altogether. The globular form often merges impercep- tibly into the urceolate, or urn-shaped — indeed, a single spray of Heath will sometimes show both forms (fig. 431)— but a better example of an urceolate flower than the Heath is the Whortleberry (Vacci- nium myrtillus), the corolla of which might have furnished designs to the sepulchral-urn- makers of ancient Etruria (fig. 422). As a rule, only insects with a proboscis long enough to reach from the ex- terior to the base of the corolla, where the honey is lodged, can reach that coveted treasure, as the opening is too narrow to admit the bodies or even the heads of the majority of nectar-sipping insects. A curious and exceptional form of corolla is the mitraeform or mitre- shaped (fig. 423). It occurs in the Grape Vine (Vitis vinifera). The five petals, which are coherent at their tips, form a dome-like covering to the stamens and ovary ; but they are green and insignificant, and hardly dis- . tinguishable from the foliage ; on which account they are valueless as insect lures. The plant, therefore, does well in getting rid of them as soon as possible, Photo by] [E- Step. FIG. 429. — YELLOW TOADFLAX (Linaria vulgaris), With personate or mask-like corolla. The upper and lower lips close tightly to keep out alUinsects but bees. 350 HUTCHLNSON'S POPULAR BOTANY FIG. 430. — FIGWORT, With sub-slotxne corolla. Adapted for pollination by wasps. and this is effected in a beautiful manner. The petals become detached at their base, and curl up spirally— that is to say, towards their common point of attachment at the apex of the flower ; and in this condition they remain till, by the expanding of the stamens, they are thrown off completely. A more interesting, because more intricate, form of irregular flower than any which we have yet considered is that which constitutes the characteristic feature of the well-known and extensive sub-order of Legummosge, to which the Pea and Bean belong — namely, Papilionacese. This name at once suggests the form of the corolla, which Tournefort and Ray, and the early botanists generally, conceived to bear a resemblance to a butterfly with expanded wings. Papilio is the Latin word for '; butterfly," and hence the corolla came to be called papilionaceous and the sub-order Papilionacese. But it was reserved for a modern philosopher to advance the startling suggestion that possibly the first butterflies were flowers ''which got loose from their stalks and flew away " ! Papilionaceous flowers are pollinated almost exclusively by bees, to which the several parts of the corolla bear the most evident relation. The reproductive organs (stamens and pistil) are contained in the two inferior petals (fig. 428), which cohere to form the keel or carina (cc), the latter an excellent contrivance for protecting the anthers from pollen-feeding insects and from rain. The lateral petals (a a)— known as the wings or alec — besides affording a platform for bees, serve as a lever to depress the keel, as well as to bring it back to its place after depression, if repeated insect-visits are necessary for pollination. Lastly, the large posterior petal, which is known as the standard or vexillum (v), gives conspicuousness to the flower, as well as closes the entrance to the nectary from behind, so that insects seeking honey must sit either on the keel or wings. We must not conclude these remarks upon the forms of calyxes and corollas without some reference to composite floweis A composite flower is really a number of florets crowded together on a single base or receptacle, such as we find, for instance, in the flower-head (capitulum) of a Daisy (BMis perennis) or Dandelion (Taraxacum officinale). We have chosen for illustration the flower-head of a Chrysanthemum (C. carinatum), the florets FIG. 431. — HISPID HEATH. of which are more easily distinguished than are complete flower (upper), and the same those of the commoner flowers above named. after removal of calyx and corolla, to -ITTI n ^oo\ • -in show position of stamen* and pistil. What yOU S66 (fig. 4do) IS a Section, the flower- 351 352 HUTCHINSON'S POPULAR BOTANY FIG. 433. — ANNUAL CHRYSANTHEMUM (Chrysanthemum carinatum). Section througn a flower-head (capitulum) to show how the numerous florets are arranged upon the receptacle. head having been cut through longitudinally in order to exhibit a perfect row of the disc florets. Each of these florets, which you will observe are tubular in form, is a perfect flower, capable of setting seed. The corolla- tube covers at its base the ovary, and hides from view the greater part of the styles, the only portion, visible being the end which bears the branched stigmas. Surrounding the flower-head are some florets of another kind, each of the so-called petals being a female flower, or, in scientific parlance, a rayed floret with ligulate (i.e. strap-shaped) corolla. One of the great purposes effected by the massing together of the florets in composite flowers is admirably suggested by Kerner in his remarks upon the taking up of pollen by insects. " Great quantities of pollen," he tells us, " adhere to the under parts of insects in the case of composite inflorescences. Shortly after the opening of the corollas the style bearing an external load of pollen is exserted from each of the little tubular and ligulate florets composing the capitulum in this group, and, owing to the fact that large numbers of these florets invariably open simultaneously, numbers of styles laden with pollen project close together from the discoid head. A largish insect settling on a capitulum may therefore be dusted with the pollen of numerous florets at once." Darwin observes that the ray-florets of composite flowers protect the florets of the disc by folding inwards at night and during rainy CLOSE-HEADED BEFARIA (Befaria coarciata). The Befarias are a genus of plants related to the Rhododendrons. The species illustrated is a native of the Alpine districts of Peru. The apparently crowded, but really alternate leaves are oblong, smooth and leathery, with grey undersides. The purple flowers form a terminal corymb, and their footstalks and sepals are covered with rusty cotton. FLORAL FORMS AND THEIR RELATIONS TO INSECTS 353 weather. Composite flowers constitute the largest order in the Vegetable Kingdom (Composite), about one-tenth of the Flowering Plants belonging to it. A characteristic of this order not yet touched upon, yet intimately con- nected with our present subject, is the production of a pappus from the limb of the calyx. Two forms of such hairy crowns are the sessile and the stipitate. The formation of a pappus is looked upon as a modification of the calyx. It is made subservient, as every child knows, to the scattering of the fruit. In not a few flowers the corolla is provided with a supplementary organ known as the corona or crown, sometimes called the paracoroHa, which in some cases is small and inconspicuous, and in others large enough to add materially to the beauty or singularity of the plant. A corona is one of the dis- tinguishing marks of the large genus Narcissus, to which our own "Wild Daffodil (Narcissus pseudo-narcissus] belongs. In a less exaggerated form this " corona " will be found also in the Forget - me -not (Myosotis) and Primula. Henslow (Journal of the Linnean Society, vol. xvi., 1877) re- gards it as a de- velopment of a fold in the inner epider- mis of the corolla. In the well-known Poet's Narcissus (AT. poeticus] the white crown is surrounded by a cinnabar-red border, which is probably a means of attracting in- sects ; and in most species of the family this organ is either delicately marked or the Photo ^ [/?. step. Whole of the FlG' 434' — HENBANE (Hyoscyamus niger). The yellow corolla is veined with purple, and the urn-shaped calyx is persistent. The IS OI a seed-vessel is a box or pyxis with a well-defined lid. 354 HUTCHINSON'S POPULAR BOTANY deeper colour than the rest of the perianth. The crown of the Passion- flower (Pasaiflvra), which in some species is single, in others double, is split up into narrow threads which Fritz Miiller, a naturalist who has given much attention to the mechanism of floral organs, believes to be of service in detaining small insects in the lowest chamber of the flower, and keeping them caged for humming-birds, the chief pollinators of many species of Passiftora. In the White Dead-nettle (Lamium album) there is a circle of hairs in the narrow part of the corolla-tube, near the base, which s'erves the purpose of excluding flies and small bees from the nectar, these being useless to the plant. The corona of our beautiful bog-flower, Grass of Parnassus (Parnassia palustris), is very interesting. It consists of five scales (the nectaries) terminating in hairs, each of which is surmounted by a yellow FIG. 435. — ANTHERS AND THEIR DEHISCENCE. (a) Longitudinal, (5) transverse, (c) valvular, (- vertidllata) that "the FlG' 443.-MAB8H CALLA (Calla palustris). . The white spatbe serves as an aliglitintr platform for the flies that are attractea Calyx IS SWOlien, and by the unpleasant odour to pollinate the flowers. the lower part of the corolla-tube is bent at right angles within the calyx ; the honey is thus guarded from Bombus mastrucatus, which tries in vain to reach it." In the Canterbury Bell (Campanula medium") the tough inflated hairy calyx, with its valvate divisions, stands above the ovary, the nectar being sufficiently guarded by the expanded bases of the five stamens which surround it (fig. 436 a); while in Clarkia (fig. 4360) the curious boat- shaped gamosepalous calyx, like the curved petals of the Cyclamen referred 362 HUTCHINSON'S POPULAR BOTANY to by Kerner, is an admirable contrivance for keeping out small wingless insects. "We have seen how perfectly the flowers of Antirrhinum and Toadflax are adapted for the exclusion of certain intruders, and many equally perfect adaptations of corolla and calyx might be enumer- ated, where the same end is to be gained. In a number of in- stances, the corolla " forms a narrow tube, still further protected by the presence of hairs, sometimes scattered, sometimes, as in the White Dead-nettle, forming a row. In others the tube itself is so narrow that even an ant could not force its way down ; while in some of the Gentians the opening of the tube is protected by the swollen head of the pistil. ... In Clover (Trifolium), Birds- foot Trefoil (Lotus), and many other Leguminosse, the ovary and the stamens, which cling round the ovary in a closely fitting tube, fill up almost the whole space between the petals, leaving only a very narrow tube. In still more numerous species the access of ants and other creeping insects is prevented by the presence of spines or hairs, which constitute a veritable cheval de frise. Often these hairs are placed on the flowers themselves, as in some Verbenas and Gentians. Occasionally the whole plant is more or less hairy ; and it Photo by-] FIG. 444. — MARSH MARIGOLD (Caltha palustris). A splendid Buttercup whose brilliance is due to the golden sepals, t petals being absent. [K. Step. Photo by] [E. Step. FIG. 445. — PURPLE LOOSESTRIFE (Lythrum salicaria). The flowers, though outwardly all alike, are of three forms, differing in the length of the pistils and the filament of the stamens : a plan that secures cross-pollination. NORTHERN' TEMPERATE REGIONS and AUSTRALIA. 363 364 HUTCHINSON'S POPULAR BOTANY will be observed that the hairs of plants have a great tendency to point downwards, which, of course, constitutes them a more efficacious barrier " (Lord Avebury). Lastly, in not a few cases creeping insects are kept away from the interior of the flower by viscid secretions on the stem or calyx, to which the unfortunate visitors get glued, and from which there is usually no escape. Thus the calyx of Plumbago (fig. 442) is furnished with glandular hairs, which stand out horizontally from the epidermis, and are fatal to mairy a wandering aphis and small fly. The Honeysuckle (Lonicera) is another familiar instance of a flower which produces these viscid protective hairs on its calyx, but in the Catchflies (Silene nutans and S. noctiflora) they are much more effective, as may be judged by the number of small insects usually found glued to the calyx and flower-stalk. The Tutsan-leaved Dogsbane (Apocynum androsemifolium) is a plant __________________ which re- sorts to ex- treme mea- sures in dealing with un invited guests. The French call it G o b e - mouche, or Fly-gulper, and the name is well bestowed. In f act, the ~ stamens ot the flower have an ugly trick of nipping intruding flies by their probosces and detaining them as captives till death puts an end to their miseries. Then the filaments open and the dead insects are released. " Allured by the honey on the nectary of the expanded blossom," says Knapp, in his Journal of a Naturalist, " the instant the trunk [of the fly] is protruded to feed on it, the filaments close, and, catching the fly by the extremity of its proboscis, detain the poor victim writhing in protracted struggles till released by death, a death apparently occasioned by exhaustion alone : the filaments then relax, and the body falls to the ground. The plant will at times be dusky from the numbers of imprisoned wretches." More than one plant is known in which the expulsion of unremunerative visitors is effected, not by the plant itself, but by other and remunerative insects. Kerner has enumerated four of such plants — Gentaurea alpina, G. ruthenica, Jurinea mollis, and Serratula lycopifolia, all of them belonging FIG. 446. — GOATSBEARD (Tragopogon pratensis). The involucral bracts are longer than the ray-florets. (" John-go-to-bed-at-noon "). but it The flower is supposed to close at noon s seldom open so late. THE WELCOME OF THE FLOWERS 365 to the great Composite order. " The young capitula of these Composites," says the eminent naturalist, " are particularly liable to the attacks of devouring beetles, especially of Oxythyrea funesta, which bites big holes in the heads, destroying crowded flower-buds and involucral scales without the least difficulty. To meet this danger a garrison of war- like 'ants is em- ployed. Honey is secreted from big stomata on the im- bricating scales of the stijll-close d capitula in such quantities that one can see a drop of it on every scale in the early morning, while later in the day, as the water evapor- ates, little masses or even crystals of sugar are to be found. This sugar, either in its liquid or solid form, is very palatable to the ants, which habitually re- sort to these capitu- la during the period of its secretion, and to preserve it for themselves they re- seiit any invasion from outside. If one of the afore-men- tioned beetles ap- pears, they assume a menacing attitude. They hold on to the involucral scales with their last pair of legs and present their forelegs, abdomen, and powerful jaws to the enemy. Thus they remain till the beetle withdraws, if necessary hastening its retreat by squirting formic acid in its direction." It has been remarked that wingless insects are most active when the dew S$S&* - . *, to by] [E. Step FIG. 447. — MARSH LOUSEWOR'P (Pedicularis palustris). Parasitic upon the roots of other plants. It has a dull pink corolla and a reddish -green calyx. 366 HUTCHINSON'S POPULAR BOTANY FIG. 448. — FLOWER or HORSE CHESTNUT. Hermaphrodite or complete flc with stamens and pistil. has evaporated, and that this is the signal for the closing of many flowers ; but it may be doubted whether these circumstances stand in the relation of cause and effect. Flowers open and close at almost all times of the day and night ; and though in some cases the periods of their opening have distinct reference to the visits of bidden guests, it seems extremely doubtful that the periods of their closing have any reference to unbidden ones. Be that as it may, the phenomena of the open- ing and closing of flowers are full of interest, and as the subject has been named, we will offer a few remarks upon it before passing on. It is well known that Linnaeus devised a floral dock at Upsala, by grouping together plants according to the hours at which they open and close, and that for a time the growing of these flower-clocks in public and private gardens became quite a rage. In recent years Kerner has repeated the experiment at Innsbruck (47° N. lat.), and a comparison of his tables with those of the older naturalist has shown that flowers both open and close earlier in th'e day at Upsala than at the more southerly situated Innsbruck. " The result," he says, " especially the earlier opening, is probably connected with the fact that the sun during the flowering season of the plants in question rises about an hour and a half earlier at Upsala than at Innsbruck." Of the flowers in Linnaeus' clock the earliest to open was the Goatsbeard ( Tragopogon pratensis, fig. 446), a Composite flower like a large Dandelion, which has received in this country the name of John-go-to-bed-at-noon, from its habit of closing about midday. Broad o'er its imbricated cup The Goatsbeard spreads its saffron rays, But shuts its cautious florets up, Retiring from the noontide blaze. Owing to its very early opening it has been pollinated usually long before noon ; and as soon as a flower has been pollinated it either begins to close, changes colour, or casts off its now useless non-essential organs. The latest flower to open was the magnificent Queen of the Night, which unfolded its scentless white petals two hours before midnight. We approach now a new and more important division of the subject— namely, the means by which the pollen of flowers is conveyed to the FIG. 449. — SECTION OF HORSE CHESTNUT, MALE FLOWER. (or) Rudimentary ovary. There no style or stigma. 367 368 HUTCHINSON'S POPULAR BOTANY stigma as a preliminary to fertilization. The consideration of these means brings us in touch with those denizens of the insect world which may be reckoned among the bidden guests of flowers. The subject has received an extraordinary amount of attention during recent years, and is practically inex- haustible. The phenomena of which it treats are them- > selves often spoken of as fertilization, but this use of the term — albeit we con- fess to being fre- quent offenders in this respect — is hardly correct. Pol- lination is a better word. Let us begin with flowers which pol- linate themselves. Now it will be evi- dent at a glance that such flowers must bear the male and female organs on the same indi- vidual ; hence we call them bisexual or hermaphrodite. The presence or absence of one or both of the essential organs of a flower is a matter of great importance. One of IE. step. ^e commonest FIG. 451.-ASH (Fraxinus excelsior). hermaphrodite The flowers are without petals or sepals, and yet are perfect because each one consists of two stamens and a pistil. flowers IS the Buttercup (Ranun- culus}. Here the male and female organs are both present in the shining yellow cup, and hence it is not only bisexual, but perfect. Even though the Buttercup had no calyx or corolla, it would still be perfect. As a matter of fact it possesses both those organs ; and since, in addition, it THE WELCOME OF THE FLOWERS 369 possesses both pistil and andrcecium, it is said to be complete. The absence of any of the four organs— calyx, corolla, andrcecium, or pistil — renders a flower incomplete ; but only the absence of one of its essential organs (i.e. the andrcecium or the pistil) • renders it imperfect. We are speaking, of course, not of that which is accidental and abnormal, but of that which is characteristic of the flower. Thus the Common Ash (Fraxi- nus excelsior), which bears its male arid female organs on the same flower (fig. 451), but has no floral envelopes whatever, is a perfect flower ; while, on the other hand, the Arrow- head (Sagittaria), in the different species of which both calyx and corolla are al- ways present, but which bears the sexes oh different flowers, is imperfect. We need hardly add that, in both cases, the flowers are in- complete. It is, then, evident that all im- perfect flowers are either male or fe- male ; if the former, they are called sta- minate ; if the latter, pistillate — na m e s which explain themselves ; while flowers which have neither male nor female organs are described as neuter. Of this latter kind are the outer florets of some of the Composites. Now, though the sexes are often separated in the manner described, staminate and pistillate flowers are not always or necessarily borne on ii— 6 Photo by] FIG. 452. — SALLOW (&alix caprea). IE. Step. The spray on the left consists of the male catkins, the so-called "palm" ; that on the right is made up of female catkins. 370 HUTCHINSON'S POPULAR BOTANY FIG. 453. — HENBIT (Lamium amplexicaule). (a) Perfect flower ; (6) cleistogamic flow( (c) section of (6). different plants. We might, indeed, liken the androecium and pistil to tenants in a house where the rooms are flowers and the house itself is the plant. When, as in the Oak (Quercus robur), Walnut (Juglans regia), and Sweet Chestnut (Castanea saliva, fig. 450), the male and female flowers occupy the same house, they are said to be monoecious (Greek monos, one, and oikos, house) ; when, as in the Juniper (Juniper us), Poplar (Populus), and Willow (Salix. fig. 452), the sexes not only occupy different rooms, but different houses, being borne on distinct plants, the flowers aie appropriately termed diwcious (Greek di, two. and oikos). Hence, too, the plants themselves are capable of sexual classification, some being male, others female, others bisexual, and a fourth class, in which male, female, and hermaphrodite flowers are found on one and the same individual, polygamous. With this digression, let us revert to the subject which led to it — the pollinating of a flower by its own anthers. The process of self-pollination is the first stage of autogamy, which, as already explained, is the fecundation of a flower by its own pollen ; and the whole process may, and sometimes does, take place without the flower opening at all. It has, indeed, been discovered by comparison of several closely allied flowers that the smaller ones are frequently self-pollinated — nay, that in some cases the same plants which produce ordinary cross-pollinated flowers produce minute self- pollinated ones which never open. Thus we may say that there are two kinds of autogamous flowers — those which open like ordinary flowers, and those which remain closed. A glance at an example or two will make the fact additionally clear. To take the last-named first. These, as the whole process is effected in the closed flowers, are called cleistojamic, a name derived from the Greek Ideistos, closed, and gamos, marriage. The Henbit Dead-nettle (Lamium am- plexicaule} offers excellent examples of cleistogamic flowers. The richly tinted reddish-purple corollas of the. expanded blossoms of this not uncommon weed are familiar to most persons FIG. 454. — FLOWERS OF Myosotis IN SECTION. (a) Wood Scorpion-grass ; (6, c) Yellow and Blue Scorpion-gra (d) Forget-me-not. Photo fty] IE- Step. HH |v !"' [ " t Et FIG. *55. — HARD HEADS (Centaurea scabiosa). A beautiful composite flower, with all the florets rayed, and of a bright purple colour. The overlapping bracts ol the involucre have toothed brown margins. EUROPE, SIBERIA, W. ASIA. 371 372 HUTCHINSON'S POPULAR BOTANY (fig. 453, a). They are met with in dry and sandy fields during the sultry months of July and August ; but few probably have noticed, earlier in the year, the small bud-like unexpanded flowers of this plant (fig. 453, 6). These are cleistogamic flowers, which never open — undeveloped flower- buds, with anthers and stigmas that mature so that perfect fruits are pro- duced. Were you to open one of these buds at the moment of pollination (fig. 453, c), you would find that thev long and flexible style (st) had curled round so as to bring the inner side of its forked stigma in con- tact with one of the anthers. Perhaps you would even find that the anthers had not opened, but that the pollen- tubes had perforated its delicate walls and were growing in the direction of the stigma. The Dog-violet (Viola canina) is another plant which produces these un- developed flowers. Pro- fessor Ainsworth Davis re- marks that " in summer the ripe fruit of the cross- pollinated flowers will be found, and, close to them, minute bud-like structures. These are the cleistogamic flowers ; their anthers are so placed that the pollen-grains can send their tubes straight to the stigma. Such a flower produces, perhaps, only two hundred pollen- grains, as opposed to some thousands in an ordinary blossom." As a rule, indeed, cleistogamic flowers are pollen saving. Thus, a single self-pollinating flower of Wood-sorrel (Oxalis acetosella) contains about four hundred grains ; a flower of Touch- me-not Balsam (Impatiens noli-me-tangere) about two hundred and fifty ; and of Cut-grass (Leersia) not above fifty. Contrast these figures with the number of pollen-grains in the Peony, 3,500,000, or in a single flower- head of Dandelion, 365,000 ! FIG. 456. — GREAT WILLOW-HERB (Epilobium hirsutum). (a) Flowering branch ; (b, c) stamens and pistil arranged for cross- pollination. In (d) the stigma-lobes have curled back to effect contact with the anthers of the shorter stamens. THE WELCOME OF THE FLOWERS 373 There is a species of Bitter-cress (Cardamine chenopodifolia) which has cleistogamic flowers that burrow into the earth. They spring from underground runners or stalks, and are produced earlier than the open flowers, which are borne upon aerial shoots. Charles Dar- w i n and others have asserted the same thing of the cleisto- gamically produced capsules (seed-vessels) of the Violet ; but Professor Henslow, in his Origin of the correctness that they cer- tainly are "very, if not more, fre- quently, not buried at all, but only con- cealed be- neath the foliage." In the cleistogamic flowers of the C o m m o n Wood-sorrel (Oxalis acetosella) the un- opened corolla forms a sort of cap, which may be removed entire, al- though, in the flowers that open, the petals do not cohere at all. The production of cleistogamic flowers appears to depend upon FIG. 458. — CLIMBING COB^EA (Cobcea scandens). Section of flower in first stage of development ; and fruit. Floral Structures, appears to doubt of the observation. He explains FIG. 457. — MORNING GLORY (Ipomcea pur- pur ea). (k) Calyx ; (c) corolla ; (s) sta- mens ; (st) stigma. FIG. 459. — CLIMBING Section of flower in third stage of development. 374 HUTCHINSON'S POPULAR BOTANY FIG. 460. — MEADOW CRANESBILL (Geranium pratense). A protandrous flower. FIG. 461. — BIRTHWORT (Aristolochia clematitis). Section of flower showing palisade hairs and essential organs. various causes, the chief of which are the time of blossoming and the influence of climate. Of these causes the latter is the most important. In Southern Italy, for example, the climate can develop normally expanding flowers, and render them fertile, so that cleistogamy is sup- pressed ; whilst here in England the climate is seemingly not sufficiently warm to do this, and cleistogamic buds appear as com- pensation. The vegetative energy comes to the fore during the summer, but ex- panding flowers are not produced simul- taneously with it; indeed, as Henslow observes, " it is not until the vegetative period has ceased, and the materials are remade for their development, that larger flowers are again borne " — that is to say, " later in the year, as in November, and also in the following spring." We come now to the second class of autogamous flowers — namely, those which develop in the normal way, and expand (or, at least, are capable of expansion) at the period of maturity. This class, as has already been explained, comprises all self-pollinating flowers which are not cleistogamic. It must not be supposed, however, that self-pollinating flowers are never cross-pollinated. As a matter of fact, the former process is often only adopted as a last resource. The various species of Myosotis offer interesting illus- trations of this truth. Thus the Wood Scorpion-grass (M. sylvatica) is usually cross-pollinated by flies ; but if no insects appear, the anthers shed their pollen directly upon the stigma, which lies con- veniently below it (fig. 454, «). The Yellow and Blue Scorpion-grass (M. ver- sicolor) protrudes its stigma from the flower when ready for pollination (fig. 454, 6) ; but if the usual agents in this process — bees and flies — do not appear, Photo by} FIG. 462. — SHEPHERD'S PURSE (Capsella bursa-pastoris). A common and ubiquitous weed whose inconspicuous flowers are self-pollinated. They hare no nectar and no scent. Found ll TEMPERATE CLIMATES. 375 376 HUTCHINSON'S POPULAR BOTANY FIG. 463. — ASPIDISTRA. Section of flower, showing sessile anthers and mushroom-like stigma. the corolla-tube elongates, and by that means its sessile anthers, which form a circle on the interior surface of the tube, are rubbed against the knotted stigma (fig. 454, c). In the Forget-me-not (M. palustris) anthers and stigma are on a level, so that self-pollination is sure to take place in the absence of insects (fig. 454, d). Take the Common Groundsel (Senecio vulgaris), again. It is one of the Composites, and each of its capitula bears from sixty to eighty inconspicu- ous tubular florets, which vary in length from one- tenth to one-eighth of an inch. Marginal or rayed florets, which might serve to attract insects, it has none, and hence, though the honey is easily ac- cessible, the plant seldom gets visited. In this case, therefore, self-pollination takes place almost as a matter of necessity. The styles are furnished at their tips with tiny brushes, which sweep out the pollen-grains in a most effectual manner, holding them fast to the edges of the stigmas, into which the delicate tubes push their way. Perhaps such diminutive flowers as those of Myosotis and Groundsel are not the best examples that might be chosen to illustrate the facts before us, and it will be helpful to name a familar flower of larger growth, which, though normally cross-fertilized, occasionally pollinates itself. Such a flower is the well-known Garden Convolvulus (Ipomoea purpurea, fig. 457). "Whilst the flowers are young," says Darwin, " the stigma projects beyond the anthers, and it might have been thought that it could not have been fertilized without the aid of humble-bees, which often visit the flowers: but as the flower grows older the sta- mens increase in length, and their anthers brush against the stigma, which thus receives some pollen." Its action, indeed, resembles that of Myosotis versi- color, save that the bringing of the anthers to a level with the stigma is effected by the lengthening of the stamens — not of the corolla-tube. Kerner asserts that the process of au- togamy or self-pollination in Ipomosa, is further facilitated by the involution of the corolla, which occurs at the close of flowering, whereby the anthers coated with pollen are pressed against the FIG. 464. — OXLIP (Primula elatior). stigma. (a) Pin-eyed and (b) Thrum-eyed flowers. Self-pollination by means of the THE WELCOME OF THE FLOWEES 377 style, which we have described as taking place in the Groundsel, may be seen to more advantage in the larger florets of most species of the Knap- weed family (Centaur ea, fig. 455), as well as in most of the "Willow-herbs (Epilobium, fig. 456). Take, for instance, the beautiful Mountain Centaury (Gentaurea montana). This plant has a very long list of insect visitors, and yet, when need so requires, the florets are quite competent to pollinate themselves. The anthers are united into a tube which conceals the greater part of the style and is itself almost concealed by the corolla-tube. The anthers open to- wards the style, upon which in consequence they shed their pollen (introrse dehiscence), and, as might be expected, a good deal of the precious dust gets scattered on the hairs. Here, unless removed by insect agency, it remains until the florets enter upon their last stage ; when the style-branches roll back, and in so doing bring their stigmatic surface in contact with the pollen on the circlet of hairs. Thus autogamy is effected. To describe even a tithe of the means by which the same important end is brought about in other flowers would require more space than the scope of this work allows. In the case of pendent flowers like Sol- danella, where the style projects beyond the stamens, the pollen may get sprinkled on the stigma ; and this may also be the case in upright flowers when the anthers are placed above the stigmatic surface, as in the Lilac (Syringa). We have seen how the lengthening of stamens may bring about autogamy, and instances are not un- common in which the curving or erecting of those organs fulfils the same purpose. The pistil, too, may shorten or elongate, curve or straighten, when self-pollination is the object ; or (as in the case of the Mountain Centaury above described) the stigma itself may be adapted to this end. The important part which the petals sometimes play in this process was Photo by] [/?. Step. FIG. 465. — PURPLE LOOSESTRIFE (Lythrum salicaria). See also fig. 466. 378 HUTCHINSON'S POPULAR BOTANY clearly indicated in what was said concerning the elongation of the corolla- tube in Myosotis versicolor ; nor is this the only means by which autogamy is effected by the corolla. In gamopetalous flowers, like the Foxglove (Digitalis], the end may be gained by the loosening and falling of the corolla, the adherent stamens brushing against the stigma as the corolla slips along the style, while in flowers with free petals the very closing of the corolla may ensure self-pollination. An excellent illustration of this last method is afforded by the Devil's Fig (Argemone mexicana), whose handsome yellow flowers bloom only for a single day. Kerner remarks that " in the morning, as soon as the petals are wide open and the tension of the sheath of stamens surround- ing the pistil is somewhat relaxed, there is an imme- diate fall of pollen on the concave sur- faces of the petals. . . . When the evening comes the petals close up over the pistil, and one of them brings its inner surface, which is covered with pollen, into direct contact with the stigma." Apro- pos of this subject, it has been ob- served of the Water- crowfoot (Ranunculus aqua- thai when the stream in which it is found is much swollen after rain, the flowers remain submerged and fertilize themselves without opening. In the beautiful Climbing Cobsea (Cobcea scandens) we see how autogamy may be effected by a co-operation of movements. On the expansion of the bud, insect-pollination is the first object provided for, and while the cam- panulate corolla nods invitingly on its stem, the anthers, which are borne on long filaments with hairy bases, lie right in the mouth of the bell, just where the first humble-bee visitor will be sure to knock against them (fig. 458). During this stage the style remains out of sight, with its three-forked stigma tightly closed. In the second stage, anthers and stigma change places, and the filaments of the former, lengthening considerably, twist themselves up FIG. 466. — PURPLE LOOSESTRIFE (Lythrum salicaria). Illustrating the trimorphism of these flowers. The calyx and corolla have been removed. 379 380 HUTCHINSON'S POPULAR BOTANY like corkscrews. This is the insect's last chance, and now, should no fertili- zation have taken place, the flower enters upon its third and final stage. For this, it assumes a completely pendent position (fig. 459). While anthers and stigma draw together, the branches of the latter open and present their stigmatic surfaces, and, finally, the pollen falls upon them. On the whole, it is a wonderful instance of the parts of a flower co-operafcing to a given end. From what has been said it will be abundantly clear that though the pollen of a bisexual flower may effect the pollination of that flower, such a result is by no means inevitable ; indeed, as a matter of fact, a very large number of bisexual flowers are almost always cross-pollinated ; and Darwin has shown pretty conclusively that in many plants cross-fertilization has a distinct advantage over self-fertilization — at least, for some generations — inasmuch as the flowers thus crossed produce more numerous seeds and healthier seedlings. This is not the place to discuss the much-debated question whether, in the long run, plants are gainers by cross-fertilization. It is a point upon which botanists are still divided. One eminent observer, Professor George Henslow, says emphatically that habitually self -fertilized plants are the most prolific, and that our previous ideas, based upon Darwin's experiments and theories, are all wrong, and must be re- versed. " The most conspicu- ous flowers and regularly (if at all) fertilized by insects are not," he asserts in his The Making of Floivers, " the best off; but they cannot help them- selves. The responsive power within them is automatic, so to say, and not volitional. What- ;J^| J ever an insect does to them, ^^^ they must yield to it, and grow f in adaptation to it, but while / they are thus being stimulated m to become what ive may choose m to call finer flowers and hand- • somer plants with larger • ^^ leaves and so on, yet all this is secured at a sacrifice of fertility." He contends that though Darwin proved that FIG. 468. — INDIAN CROCUS (Ccelogyne lagenarw). ^ . intercrossing is a stimulating A beautiful Orchid whose lip is veined and striped to provide . a honey-guides for insects. See also fig. 470. pTOCeSS at least, for a time THE WELCOME OF THE FLOWERS 381 his experiments also went to show that "when the two processes were continued for a few years the plants derived by successive self-fertili- zation in a few genera- tions not only recover themselves, so to say, but sooner or later sur- passed in fertility the descendants of plants successfully intercrossed for the same number of years." However, the fact re- mains. Cross-fertiliza- tion occurs much more frequently in Nature than self-fertilization ; and this truth may be readily accepted without committing oneself to the dictum of Darwin — which, indeed, is no longer taken seriously by competent botanists — that Nature abhors self-fertilization. A via media between Darwin and Henslow is offered in Step's Ro- mance of Wild-flowers : ( Capsella bursa-pastoris) V-.A. ^r s..A . --.»V." . :,JLA ,>> FIG. 469. — LAMB'S-EAK PLANTAIN (Plantago media). With wind-pollinated (anemophilous) flowers. " The small but ubiquitous Shepherd's Purse may be taken as a type of the inconspicuous- flowered weeds of this family [Cruciferce], which fertilize themselves, and produce such abundance of seed that they take possession of all cultivated ground so soon as the husbandman's back is turned. Their flowers range in diameter from one-fourth to one-twelfth of an inch, and in some cases the petals have been converted into stamens as being more useful to plants once dependent upon the visits of insects, but which have now learned to do without them. The presence of these minute white petals, and in some cases honey-glands that no longer secrete honey, testifies to the fact that these plants have come down in the world. Yet, in spite of their lack of show or ' presence,' they are a standing rebuke to those writers who have 382 HUTCHINSON'S POPULAR BOTANY FIG. 470. — INDIAN CROCUS. Lip of flower showing fringes and streaks of colour — honey-guides. so strongly asserted that cross-fertilization pro- duces a more vigorous and successful race. What cross-fertilization by insect agency does is to produce more brilliant individuals, and to keep up large flowers of bright hue. In fact, it produces a kind of floral aristocracy ; whilst the principal work of the vegetable kingdom — the abstraction of carbon from the atmosphere, the setting free of oxygen, the production of food for the entire animal races — is done mainly by the less brilliant weeds and grasses and trees — the working classes." We have seen how certain bisexual flowers adapt themselves to self-pollination ; we may next consider how another class of flowers, also bisexual, provide against it. This brings us to the phenomena of dichogamy, upon which we must say a few words. The term is derived from the Greek dicha, in two parts, and gamos, marriage ; and whenever the reproductive organs (stamens and pistil) of a bisexual flower mature at different times we have an instance of dichogamy, and the flower is said to be a dichogamous flower. When the stamens mature first, so that the pollen in their anther- lobes escapes before the stigma in the same flower is ready for pollination, the flower is said to be protandrous (Greek proteros, before, and andros, male) ; and this is the case in most species of Geranium,, Pelargonium, Malva, Umbel liferse, Composite, and Campanulacese. When, on the other hand, the stigma matures and loses its capacity for pollination before the anthers of the same flower have shed their pollen, the flower is said to be protugynous (Greek proteros, before, and gune, a female). Some species of Magnolia., ArisLolochia, Scrophularia, and Plantago have protogynous flowers, but they are much less common than are the other kind. The Meadow Cranesbill (Geranium pratense, fig. 460) — the largest of our British Cranesbills — is a good example of a protandrous flower. It might at first sight be thought to be a self-pollinating flower, for at the time when the anthers dehisce they are bent right over the pistil; but at this stage in the flowering the pistil is imma- ture, and the stigmatic tissue is protected from pollen falling upon it. At a later period, how- ever, when the anthers have di- FIG. 471.— INDIAN CROCUS. verged from the pistil, the latter Hairsof a portion of two of the fringes of the lip highly magnified. matures, its five branches 6X- 383 HFTCHIXSON'S POPULAE BOTANY pand. exposing the stigmatie surface, and the dower is cross-pollinated by insect agency. The Common Birthwort t,Ari*tolochia dematitis] is a remarkable instance of a protogynous nower. Fig. 461 shows a section through the swollen base of the dull yellow perianth, in the interior of which we see the six-lobed stigma and a few of the anther-lobes, which are sessile on the short style. Xow the stigma of this Birthwort matures two or three days before the anthers are ripe, and at the time of its maturity the riower is entered by small black midges of the genera Cerat&pogon and Ckironomus. It will be noticed that the dull yellow corolla of the tiower is swollen at the base, but contracts above into a tube which is lined, in the first stage of the nower. with stiff downward- pointing hairs. Along this tube the midges crawl in quest of refresh- ment, which they find in the succu- lent tissue that forms the smooth walls of the roomier chamber below. From the centre of the fioor of this chamber uprise the six short sta- mens, the anther-lobes of which are adnate to the stigmatic column. Their meal finished, the midges rest awhile, soothed by the warmth of the apartment. Then they turn to depart. But egress is a different thing from ingress, and on crawling to the tube they find that escape is cut off. The hairs which they had passed over so easily are now a stockade of bristling points. The little guests are prisoners ! What is to be done "? At first the midges take the calamity with calmness, and explore their prison with evident care. In the course of their explorations they crawl over the stigmatic surface and — supposing them to have come from another fiower — fertilize the ripe stigma with the pollen which they have brought thither. Hours pass away : the stigma withers : but the midges are still held captive. A whole day goes by — two days — and release seems as far off as ever. They become anxious and restless. On the third day the anthers open and discharge their pollen, and the midges, worked up by this time into a fine bustle of alarm, get repowdered with the yellow meaL Their term of imprison- ment is now at an end. for lo ! the prison bars have collapsed — the stockade of hairs has completely withered, and the midges pass easily out of the nower. laden with an abundant freight ! FIG. 473. — TIGER-STRIPED OXCTD (Oncidium tiprinum). An Orchid VARIKGATKI) OXCID (Oncidivm e, Tlie Oncidiums are a genus of Orcliids of which about two hundred and fifty species are kr The Variegated Oncid of the West Indies. THE WELCOME OF THE FLOWERS 385 In the well-known window-plant, Aspidistra elatior, the flowers are some- times protandrous and sometimes protogynous, and self-fertilization is still further guarded against by the curious mushroom-like stigma, which covers the anthers umbrella-fashion, so that the stigmatic surface is quite out of reach of pollen from the same flower (fig. 463). '' The capitate stigma closes the flower, leaving only four small openings through which Delpino supposes small flies to enter ; the pollen falls out of the anthers and lies in the cavity of the flower. The flies emerge all dusted with pollen, and alighting on the stigma of another flower place pollen there before they FIG. 474. — FORGET-ME-NOT (Myosotis palustris). A well-known streamside flower with yellow-centred sky-blue corolla of salver shape. [E. Step. find the small entrance" (Miiller). These remarks apply equally to the other species of Aspidistra — A. lurida, punctate^ etc. > The flowers referred to are also visited by numbers of Podura, probably for the sake of the pollen, some of which they may carry from flower to flower. An even more curious way in which bisexual flowers lay themselves out for cross-fertilization without irregularity is known as heterostylism. The law is well illustrated in many plants of the Primula family, to which the Primrose, Cowslip, and Oxlip (fig. 464) belong. " Most children are aware," says Grant Allen, "that we have in our woods two kinds of IT— 7 386 HUTCHINSON'S POPULAR BOTANY Primroses, which they know respectively as pin-eyed and thrum-eyed. In the pin-eyed form, only the little round stigma is visible at the top of the pipe, while the stamens, here joined with the corolla-tube, hang like little bags half-way down the neck of it. In the thrum-eyed form, on the other hand, only the stamens are visible at the top of the tube, while the stigma, erected on a much shorter style, occupies just the same place in the tube that the stamens occupied in the sister blossom. Now each Primrose-plant bears only one form of flower. There- fore, if a bee begins visiting a thrum-eyed form, he will collect pollen on his probos- cis at the very base only ; and as long as he goes on visiting thrum- eyed flowers, he can only collect, without getting rid of any grains on the deep-set stigmas. But when he flies away to a pin- eyed blossom, the part of his proboscis which collected pollen before will now be opposite the stigma, and will fertilize it ; while at the same time he will be gathering fresh pollen below, to be rubbed off on the sensitive surface of a short-styled flower in due season. Thus every pin-eyed blossom must always be fertilized by a thrum-eyed, and every thrum-eyed by a pin-eyed neighbour." Heterostylism is carried to an extreme in trimorphic flowers, where, besides a long- and a short-styled form, we get a third condition, to which Darwin has applied the name " mid-styled." The flowers of Purple Loosestrife (Lythrum saticaria, figs. 445, 465) offer, perhaps, the best examples of trimorphism. The three forms are shown with diagram- matic stiffness in fig. 466, the floral envelopes (calyx and corolla) having previously been stripped off. Comparing the different forms : in the left- hand figure there are six short stamens, six mid-length stamens, and a long style ; in the central figure there are six short stamens, six long ones, FIG. 475. — FLOWER-BUDS OP Aralia nudicaulis. ingle flow< (a) Umbel of unopened flowers ; (6) (c) umbel at an ear 3rmal growth of stage of growth . & OBJ If ff 1-1 S til III 387 388 HUTCHINSON'S POPULAR BOTANY •and a mid-length style ; and in the right-hand figure, six mid-length stamens, .six long ones, and a short style. Now the singular fact about these flowers is this : the long-styled forms are almost invariably fertilized by pollen from long stamens; the mid-styled forms by pollen from mid-length stamens ; and the short-styled forms by pollen from short stamens ; and hence, of course, the flowers are usually cross-pollin- ated. Darwin, in- deed, has shown that when fertiliza- tion takes place under other condi- tions — when, for instance, a long- styled flower is pollinated by short or mid-length sta- mens— the seeds produced are smaller and less healthy. Hermann Miiller tells us that when the flower of Purple Loosestrife is fully expanded — which, however, owing to the crowded nature- of the spike, is not often — " the upper petals stand vertic- ally while the lower project obliquely forward ; and the latter form, there- fore, a rudimentary platform for insects. The irregularity in position of the stamens and pistil is of more importance ; they all occupy the inferior (outer) part of the tube, so that insects cannot Breach the base of the flower between them, but only above them ; and their ends are bent upwards, so that the under surface of the insect must come in contact both with anthers and stigma. Honey is secreted by the fleshy base of the flower, and surrounds the short stalk of the ovary, and fills the space FIG. 477. — FIG (Ficus carica). Longitudinal section through hypanth odium, showing the flowers in the interior. THE WELCOME OF THE FLOWERS between it and the sides of the tube. Insects are attracted from a distance by the crimson spikes of flowers, and are guided on their way to the honey by the dark red colour of the inner surface of the calyx and by the dark lines in the middle of each petal. These insects are caused to perform regular cross-pollination by the trimorphism of the flowers, which forms the most remarkable feature of the plant." The arrangements in Nature for securing the cross-fertilization of plants are by no means exhausted with the phenomena of di- chogamy and heterostyly. These provisions are doubt- less the rule among insect- pollinated flowers, but there are innumerable exceptions to the rule ; and, moreover, all cross-fertilized plants do not owe their pollination to insect agency. Other ani- mals, such as snails and birds, sometimes perform this office ; and in a large number of cases wind and water are the pollen-carriers. For the present, however, we may confine ourselves to flowers that are pollinated by insects. We have already shown that many flowers are speci- ally adapted, either by their form or mechanism, for the visit of certain insects ; and further, that the colours, scents, and nectareous sweets of such flowers act as lures to the guests that are wanted. The flower, indeed, as a talented FIG. 478. — BIBD'S-EYE PRIMBOSE (Primula farinosa). A beautiful plant of northern moors and meadows with lilac-coloured flowers. Dimorphic like the Common Primrose. 390 HUTCHINSON'S POPULAE BOTANY FIG. 479.— NECTARIES. The first figure is a petal of Buttercup showing pocket- like nectary at its base ; the second a petal of Barberry with its two nectaries. writer remarks, " is no longer a simple passive victim in the busy bee's sweet pillage, but rather a conscious being, with hopes, aspirations, and com- panionships. The insect is its counter- part. Its fragrance is but the whisper of welcome, its colour is as the wooing blush and rosy lip, its portals are decked for his coming, and its sweet hospitalities humoured to his tarrying ; and as it finally speeds its parting affinity rests content that its life's consummation has been fulfilled." In considering the means by which insects are attracted to flowers, six important features may be specially noted. These are Conspicuousness, Odour, Irregularity, Honey-guides, Nectar, and Pollen. Let us take them in their order. Size, colour, and the massing of flowers are the three chief causes of Conspicuousness. Of these the first and last need not be dwelt upon. It is obvious that the larger a flower is, the greater are its chances of attracting attention ; equally obvious is it that small flowers which cluster together (say as umbels or flower-heads) have a decided advantage over flowers of the same size which are solitary. Then there is colour. The bright colours of flowers, and in some cases the bright tints of the adjoining parts, such as the flower-stalks, bracts, etc., have evident reference to the visits of insects ; indeed, it was the opinion of Sprengel, a German botanist of the eighteenth century, that " flowers differ in colour in accord- ance with the kinds of insects which frequent them." That bees readily dis- tinguish colour has been proved by Lord Avebury, and the experiments of Darwin point to the same conclu- sion. " It is a curious question," Dar- win writes, " how bees recognize the flowers of the same species. That the coloured corolla is the chief guide can- not be doubted. On a fine day, when hive-bees were incessantly visiting the little blue flowers of Lobelia erinus, I cut off all the petals of some, and only the lower striped petals of others, and FIG. 480. — LARKSPUR. A flower of Delphi Uyx i grandiflorur, ind corolla. with spurred [Walter Rossitcr Photo l>y] . FIG. 481. — MOUNTAIN DRAGON'S-MOUTH (Horminum pyrenaicum). An interesting genus, containing only one species, of the order Labiate ; the purple flowers bear in the lower part of the corolla-tube palisades of elastic hairs to protect the honeyfrom unbidden guests. M00. PARTS OF TEMPERATE EUROPE. 391 392 HUTCHINSON'S POPULAR BOTANY these flowers were not once again sucked by the bees, although one actually crawled over them. The re- moval of the two little upper petals alone made no differ- ence in their visits. Mr. J. Anderson states that when he removed the corollas of the Calceolaria, bees never visited the flowers." That this is not a rule without excep- tion, however, Dar- win has himself pointed out. He shows clearly enough that colour is not the only insect guide, and offers the com- mon-sense sugges- tion that insects may be able "to recognize plants even from a distance by their general aspect, in the same manner as we should do." We may add that the entire removal of the corollas of several flowers of the Garden Convolvulus (Ipomwa purpurea) — an experiment which we tried not long since — did not hinder bees from visiting those flowers; indeed, they seemed to resort to them more freely than to the unmutilated flowers, although the latter were fully expanded at the time. Sprengel's opinion has been quoted that " flowers differ in colour in accordance with the kinds of insects which frequent them," and it would be easy to bring forward an array of arguments in support of this view. It has been noticed, for example, that the favourite colours of the honey- bee are blue, violet, crimson, purple, and deep violet-blue, particularly the last-named ; but that scarlet, orange, and yellow attract them but little — if at all. Possibly, as Kerner suggests, the nerve-bundles which correspond to those colours are wanting in their eyes. Butterflies and humble-bees, on the other hand, are very partial to scarlet. Scarlet appears also to be the favourite colour of humming-birds ; and the fact is to be FIG. 482.— SECTION OF PANSY FLOWER (Viola tricolor), Showing spurred stamens projecting into the spur of the petal. The lateral petal will be seen to have at its base a tuft of hairs which aid the bee in clinging to the (lower. THE WELCOME OF THE FLOWERS 395 noted that scarlet flowers abound in those countries where humming-birds are found. Crepuscular and night-flying insects are most affected by white- and pale yellow, a circumstance easily accounted for, since the deeper- coloured flowers become invisible when twilight falls. Flies and beetles which frequent dung-heaps and offal are drawn to> greenish yellow or brownish yellow flowers, like the Parsley and Ivy, the Aralia and Sumach; and " this phenome- non has been explained by the similarity of the colours named with those of the dung-heap and offal generally " (Kerner). Wasps, which are so partial to decaying fruit, seem to have a predilection for dark brown ; whilst carrion- flies are most susceptible to pale fawn-red and dirty violet, the prevailing tints in decaying flesh. Hermann Miilier says of the gigantic Amorphallus ti- tanum, whose spathe is thirty- three inches in diameter, and the bare part of whose floral axis attains a length of six feet, that Pholo 6y] [e 8tep. it "is adapted FIG. 483. — CUCKOO-FLOWER (Cardamine pratensis). by its dirty Two of the sepals are enlarged at the base to accommodate the nectaries. 394 HUTCHINSON'S POPULAR BOTANY yellow and dark purple colours for dung- and carrion-flies." A more familiar example is our own little Cuckoo-pint (Arum maculatum). All such flowers give out an offensive odour which serves as an additional attraction to carrion-loving flies. Physiologically speaking, the cause of the colours of flowers (as, indeed, of fruits also) is the existence of pigments in their cells, either dissolved or in solid particles. The colouring principles are 'the same as in autumn leaves — namely, anthocyanin and phylloxanthin. Thus the yellow hue of the florets of the Dandelion is due to microscopic bodies of protoplasm tinged with a yellow pigment, which are contained in the epidermal cells ; while the colour of the Pheasant's-eye (Adonis autumnalis) is due to a red pigment. In the last-named flower the particles are less than ^Vu of an inch in diameter. In blue, violet, and (so-called) black flowers (which are probably in most cases a deep shade of violet), the colouring matter is usually dissolved in the cell-sap. White flowers do not derive their whiteness from any pigment, but from the fact that their epidermal ceUs are filled with air. Professor Thome has shown in the case of Zinnia elegans how peculiarly the separate pigments of a flower may be distributed in FIG. 484. — SAXIFRAGE (Saxifraga officinalis). The white corolla has two violet spots at the base of each petal. Pollinated by short-lipped insects, especially flies. different superimposed layers of cells. " The marginal florets of the capitulum are scarlet on the upper and light yellow on the under side, while the layers of cells nearest the surface contain a purple sap with orange granules. The rest of the cells are in which float a smaller number of light filled with a colourless sap yellow granules." The changes in the colours of flowers, like the changes in the colours of leaves, are due to oxidation. The Common Borage (Borago officinalis) changes from pink to blue ; and the pale pink bells of the young flowers of the Garden Convolvulus (Ipomcea purpurea) frequently change to a deep purple as they mature. These are familiar instances of oxidation Photo by} [Walter Rossiter FIG. 485. — -AFRICAN LILY (Agapanthus umbellatus). A Cape plant with large umbellate heads of bright blue flowers, and long strap-shaped leathery leaves, springing from a large bulb. The flower-head offers a good example of the umbel form of inflorescence. 395 396 HUTCHINSON'S POPULAR BOTANY FIG. 486. — SECTION OF PASQUE-FLOWER. (a) Stamens; (») nectaries. in cells containing the blue colouring principle (anthocyanin). Yellow flowers, on the other hand, if they change at all, keep to their own series of colours — oranges and pure reds — so that there is fitness in De Candolle's division of flowers into ocanthic and cyanic — a yellow series and a blue. Here, as elsewhere in Nature, the rule is not without exceptions. Thus, the Yellow and Blue Scor- pion-grass (Myosotis versicolor) changes from yellow in the bud to blue in the open corolla; and the Garden Hyacinth (Hyacinthus orientalis), whose generic name denotes a deep purply blue colour, is not infrequently pale yellow. Other exceptions might be pointed out. Kerner draws attention to a third colouring principle, a scarlet-red pig- ment, as yet little known ; but notably present in the blood-coloured inflated calyx of the Winter Cherry (Physalis alkekengi). It may serve, he thinks, to frighten animals. If this be so, the brilliant hues of flowers must in some instances be looked upon as means of repulsion rather than of attraction. From Conspicuousness we come to Odour. Odour and Conspicuous- ness are the two means by which insects are attracted to a plant from a distance, just as honey-guides facili- tate their search for the nectary when the flower is reached. That odours really do attract insects has been attested by Darwin, who found that they visited flowers which he had covered with muslin nets. The same naturalist tells us that " Nageli affixed artificial flowers to branches, scenting some with essential oils and leaving others unscented ; and insects were attracted to the former in an unmistakable manner. ... Of . 48 /. — INFLORESCENCE OF PETTY n n n i_ £ ^ i SPURGE (Euphorbia pepius), a11 flowers, he further remarks, .showing the horned nectaries. " white is the prevailing one : and THE WELCOME OF THE FLOWERS 397 of white flowers a considerably larger proportion smell sweetly than of any other colour — namely, 14'6 per cent. ; of red, only 8'2 per cent, are odoriferous. The fact of a larger proportion of white flowers smelling sweetly may depend in part on those which are fertilized by moths requiring the double aid of conspicuousness in the dark and of odour. So great is the economy of Nature, that most flowers which are fertilized by crepu- scular or nocturnal insects emit their odour chiefly or ex- clusively in the evening. Some flowers, however, which are highly odoriferous, depend solely on this quality for their fertiliza- tion, such as the night- flowering Stock (Hesperis) and some species of Daphne ; and these present the rare example of flowers which are fertilized by insects being obscurely coloured." Cons picuousness and Odour usually go together, but this is not always the case. The flowers of the Willow, Lime, and Mignonette are notable exceptions. The hypantho- dium of the Fig is another. What attracts the wasp to the Fig? Not the brightness of its densely packed unisexual flowers, for they are hidden quite out of sight. It is the odour. Were it not for the odour the Photo by} IE. Step. FIG. 488. — WOOD SPURGE (Euphorbia amygdaloides). erennial. The horns of the nectar i species. A larger species than the Petty Spurge, and a pen glands converge in this i 398 HUTCHINSON'S POPULAR BOTANY FIG. 489. — NECTAR GLANDS. The first figure shows a gland at the base of the ovary in Veronica ; the second is part of a cherry leaf with two nectaries (n) at its base. flower might remain unvisited and would probably never get fertilized, for the Fig is protogynous. In fact, the two kinds of Fig-tree — caprificus and jftcu.s, as the Italians call them — stand to each other in the relation of male and female, being, broadly speaking, the different sexes of the one species, Ficus carica ; and each appeals to the-olfactory sense of insects with a distinct purpose. Caprificus may be popularly regarded as the " male tree " — i.e. its hypanthodia produce male flowers near the opening (ostiole) and abortive female flowers, known as gall-flowers, lower down. Ficus is the " female tree " ; its inflorescences, which form the edible Figr contain only female flowers. Concerning these gall-flowers, some very remarkable facts are known. " As the name indicates," says Kerner, " not fruits but galls are produced from these modified female flowers, and this happens in the following manner. There is a small wasp . . . Blastophaga grossorum, which lives upon the Fig cultivated in the South of Europe. This insect passes into the cavity of the inflorescence through the orifice, and there sinks its ovipositor right down the style-canal of a flower and deposits an egg close to the nucellus of the ovule. The white larva developed from the egg increases rapidly in size and soon fills the entire ovary, whilst the ovule perishes. The ovary has now become a gall. When the wasps are mature they forsake the galls. The wingless males are the first to emerge, and they effect their escape through a hole which they bite in the gall. The females remain a little longer in the galls and are there fertilized by the males. After- wards they come out also, but only stay a short 'time within the cavity of the inflorescence, issuing from it as soon as. possible into the open air. They crawl up to the mouth of the inflorescence^ and in doing so come into contact with, the pollen of the male flowers and get dusted all over the body, head, thorax, abdomen, legs, and wings. After squeez- ing through between the scaly leaves- at the mouth of the inflorescence, and having at last reached the outside, they let their wings dry and then run off to- FIG. 490. — NECTAR GLANDS. The dark spot (n) on each of the stipules of the Broad 3ean- is a nectar gland. 400 HUTCHINSON'S POPULAR BOTANY FIG. 492. — POLLEN OF EVENING PRIMROSE ((Enothera biennis). FIG. 493. — POLLEN OF PUMPKIN (Cucurbito pepo). floral FIG. 494. — POLLEN OF PAS- SION-FLOWER (Passiflora). other inflorescences on the same or on a neigh- bouring Fig-tree." If the latter, and the tree happens to be a " female tree " in an early stage of development, the result may be anticipated. The little visitors gain an entrance, perhaps tearing or even losing their wings on the sharp scales near the aperture, and, as they bustle about the hollow inflorescence, the pollen which they have brought with them gets dusted on the stigmas, and fertilization ensues. Odorous flowers are of two kinds, fragant and foetid. The former, which are by far the most numerous, are chiefly visited by bees, butterflies, and moths ; the latter, by carrion-flies and dung- beetles. Arum crinitum, says Hermann Miiller, " attracts carrion-flies by means of its strong odour of putrid flesh. The smaller visitors are held fast by sticky hairs in the chamber and di- He elsewhere affirms that the disgusting smell of the Marsh Calla (C. palustri-s, fig. 443), serves the double purpose of attracting carrion-flies and repelling injurious animals. This remark would be equally true of the gigantic Rafflesid amoldi, many Irises, and the remarkable Dragon Arum (A. dracunculus). Kerner, with characteristic thoroughness, has proposed to divide the floral scents into five groups, which he names the indoloid, aminoid, benzoloid, paraffinoid, and terpenoid scents — a distinct im- provement on Dr. Robert Brown's threefold and somewhat empirical division into superodorants, subodorants, and inodorants. To the indoloid group belong those volatile substances which arise from the decomposition of albuminous compounds, and diffuse into the atmosphere ; and in which one or several benzole nuclei are retained, as well as nitrogen. These compose the greater number of the foetid scents ; and the flowers in which they are developed " resemble animal corpses in their colouring, having usually livid spots, violet streaks, FIG. 495. — POLLEN OF SCOTS PINE (Pinus sylvestris). THE WELCOME OF THE FLOWERS 401 veins on a greenish or fawn-coloured background." belong those and red-brown the aminoid group volatile substances which diffuse into the air and have an amine as their foundation, like the scents of Hawthorn, Ivy, and Mountain Ash. The benzoloid group comprises those scents which are formed from the so-called aromatic bodies, like oil of cloves and vanilla, and are found in the Honeysuckle, Wallflower, Pink, Violet, Lilac, and a host of other flowers. The paraffinoid scents include the vegetable acids and alcohol of those hydrocarbons which are known as paraffins, such as valerian ic acid and oil of rue. They are found in the Rose, Vale- rian, Rue, Elder, etc. The last or terpenoid group consists of scents produced from ethereal oils destitute of oxygen, called terpenes ; the well-known oil of lavender is one of them. They are usually developed in the tissues of the stems and foliage, but the Citron, Lavender, Thyme, Magnolia, and some other plants produce them in their flowers. Many flowers which are not cross-pollinated by insects, and some few that are, are quite odourless to man ; though it does not follow of necessity that they are scentless to insects. To take an example : The flowers of the Virginia Creeper (Ampelopsis quinquefolia), in which we oan detect no scent, evidently appeal to the olfactory sense of bees ; otherwise it would be im- possible to account for the readiness with which they find out the flowers, which have green corollas and are undistinguishable among the leaves at a little distance. As an instance ii— 8 To Photo by] [E. Step. FIG. 496. — TWAYBLADE (Listen ovata). An Orchid with very small flowers, but each flower with remarkable arrangements to ensure cross -pollination. 402 HUTCHINSON'S POPULAR BOTANY FIG. 497. — FLOWER OF PEA (Pisum sativum). FIG. 498. — SECTION OF PEA FLOWER after removal of calyx, wings, and standard, and one of the petals of keel. In the remaining petal are the stamens and pistil, and, in the conical cavity above the anthers, the pollen. FIG. 499. — SECTION OF PEA FLOWER depressed in the direction of t'.ie arrow. When such de- pression is ciused by the weight of a bee, the pollen-covered style-brush is forced out and strikes against the underside of the bee. of the power of smell in insects, Kerner relates that when, some years ago, the Aroid Dracunculus creticus from Cyprus was planted in the Vienna Botanic Gardens, though there were no carrion-flies in. the vicinity, nor refuse matter of any kind to attract them, the large foatid-smelling flower-sheath no sooner opened than it was freely visited by those insects, who came flying thither from every quarter. A captive Hawk-moth which the same distinguished naturalist let loose in the gardens at a distance of two hundred yards from a plant of Honeysuckle, flew directly, straight as an arrow, to the plant, and was found by Kerner, who had placed a cinnabar-red mark on the moth, hovering about over the flowers. Here again scent alone can have guided the insect. Perhaps it will now be said, If scent and colour are the two chief means by which insects are attracted to flowers from a distance, what is to detain and reward them when the flowers are reached ? In other words, What provision is made for their reception ? This question is answered by completing the list of floral attractions which we have named. Two out of the six have been already dealt with. The re- maining four are : Irregularity, Honey-guides, Nectar, and Pollen. Irregularity is specially con- nected with the comfort of the insect. Labiate flowers, for ex- ample, provide a landing-stage for their visitors, as was pointed out in the case of the White Dead- nettle. The Calceolarias, which [Henry Troth. FIG. 500. — WILD GINGER (Asarum canadense). The brown bell-shaped flowers of this plant are produced close to the ground, much like those of Aspidistra. At first the three lobes are folded over the mouth of the flower, leaving only narrow slits through which small flies, attracted by the camphor-like odour and the livid colour, enter, and are imprisoned until they have been dusted with pollen, much as in the case of Cuckoo-pint. This species is a native of North America, but there is a European species which has been naturalized in parts of England. 403 404 HUTCHINSON'S POPULAR BOTANY offer another typical form of irregular flower, not only provide a platform, but present their nectary to the humble-bee directly he has taken his seat ; the Aristolochias, which are chiefly pollinated by flies, are furnished with conveniences in the way of perches and expansions for alighting, which clearly save the little guests a world of trouble. The Orchids (figs. 468 and 473) are provided with " all sorts of lobings and sinuses, fringes, pegs, and knobs on the lower lip, which serve as landing-stages and as fulcrum s for further explorations to numerous flies, wasps, bees, humble- bees, and butterflies." So one might go on furnishing examples indefinitely. The subject is inexhaustible, though whether the irregularity should be regarded as one of the causes of insect visits, or whether it is merely an effect, as Professor Henslow would persuade us, are questions which need not be discussed in this place. The second provision in flowers for the reception of insects comprehends all those markings and accessory growths on the sepals and petals which are known as Honey-guides or Path-finders. The beautiful pencillings of flowers (spots, stripes, etc.), no less than their bright colours, serve, it is thought, to attract insects. Sprengel maintained nearly a century ago that the purpose of the marks is to guide to the nectary, a notion which Darwin for a long time scouted ; but when the latter published his baok on the Effects of Cross and Self-fertilization in the Vegetable Kingdom, he had come round to Spren gel's view, and, indeed, defended it therein. In Darwin's opinion the case of the Pelargonium affords the best evidence that these FIG. 501. — FLOWER OF SAGE (Salvia officinalis), Sb owing the mechanism as set in motion by the - of a bee. THE WELCOME OF THE FLOWERS 405 marks have really been developed in correlation with the nectary. " The two upper petals," he writes, " are thus marked near their bases ; and I have repeatedly observed that when the flowers vary so as to become peloric or regular, they lose their nectaries and at the same time the dark marks; when the nectary is only partially aborted, only one of the upper petals loses its mark. ... It is, however, evident that insects could discover the nectar without the aid of guiding-marks. They are of service to the plant only by aiding insects to visit and search a greater number of flowers within a given time than would otherwise be possible; and thus there will be a Photo by] FIG. 502. — BARBERRY (Berberis vulgaris). The yellow flowers have irritable stamens which spring up and dust insect visitors with pollen. better chance of fertilization by pollen brought from a distant plant, and this we know is of paramount importance." Hairs, prickles, the grooves of petals, and warty protuberances may also serve as path-finders ; and one or more of these features may be present in a flower in addition to the guiding-marks. This is the case in the beautiful Orchid known as the Indian Crocus (Codogyne lagenaria, fig. 468), where the yellow fringes (figs. 470, 471) borne on the lilac veins of the lip of the flower, and the striped and barred markings on either side, act as path- finders. At the same time, it must not be supposed that all the stripes, spots, etc., of flowers are guides to the nectary. Probably in not a few 406 HUTCHINSON'S POPULAR BOTANY FIG. 503. — FLOWER OF Kalmia latifolia. In the first condition the stamens are bent back and the anthers held fast in pouches of the corolla. cases their purpose is purely an aesthetic one. The Opium and Common Red Poppies, for example (Papaver somniferum and P. rhoeas), have no honey, and yet they are strikingly marked ; and in many labiate flowers and Saxifrages (e.g. Saxifraga officinalis, fig. 484) the marks are so small as to be hardly visible, at a few paces — at least, to the human eye. But, of course, if their presence is related to insect visitors they are only intended to be seen at short range — when the insect is actually on the flower. We come now to Nectar. Of all the attractions which flowers hold out to insect visitors, this is un- doubtedly the chief. Nectaries are usually, though not always, situated deep down in the flower ; and they present a variety of forms. In some flowers they have the appearance of small fleshy warts and pegs ; in others they are grooved ; in others ring- shaped ; and in the fourth case, hollowed out like spoons or shallow cups. These are the most common forms. The nectar itself " is not," says Professor Trail, "identical with honey, although, as furnished by many plants, it is the material from which bees make the latter. Analysis has shown the sugar of nectar to be, very generally, cane- sugar, while that of honey is grape- sugar, consisting of dextrose and levulose in equal proportions. The conversion of the cane-sugar is brought about by an admixture of salivary secretion at the time the nectar is sucked up. This conver- sion has been well made out in the case of bees ; and since larger animals and man are known to con- vert cane-sugar into grape-sugar as FIG. 504.— FLOWEB OF Kalmia latifolia. an initial process in digestion, it is A bee in search of nectar causes the anthers to spring from Probable that butterflies and moths the pouches and dust the visitor with poiien. effect the same changes as the bee." Photo by] IE. Step. FIG. 505. — COMFKEY (Symphytum officinale). A coarse, bristly plant that grows chiefly by watersides . The pale yellow or blue purple flowers are in scorpioid cymes . The anthers shed their pollen before the stigma is mature. Nectar is secreted by the fleshy base of the ovary, wnicn induces the visits of humble-bees. EUROPE and WESTERN SIBERIA. 407 408 HUTCHINSON'S POPULAR BOTANY FIG. 506. — POLLINIA or Asclepias cornuti. The first shows the pollinia immediately after removal from the flower. The second shows them a little later, when by the twisting of the strap- like connections they have been brought close together. FIG. 507. — Catasetum tridentatum. One of the most remarkable of the Orchids. At a meeting of the- Linnean Society a few years ago some interesting specimens of honey were- exhibited. Among these: were the Eucalyptus honey from South Australia,, which, like the plant from which it derives its proper- ties, is valued as a febri- fuge ; and a quantity of the Arbutus honey from Turkey, which is said to- produce drowsiness and sleep. The reddish honey of the Brazilian waspr which is known to be actually poisonous, was also represented in the- collection; as were the spring honey of Eastern Nepaul, which is noxious owing to the bees feeding on the nectar of Rhodo- dendrons ; the honey of Trebizond, which is an irritant and intoxicant nar- cotic because of the poison of the Pontic Azalea and Rhododendron infused through - it ; a poisonous. African honey obtained from a bee which feeds on Euphorbia flowers ; and,, lastly, a pale-looking honey from Coorg, in Southern India, of which a very small quantity is said to produce- severe headache, nausea, and prostration. Needless to- add, the honey of our English bees is perfectly innocuous- and wholesome. The position of the. THE WELCOME OF THE FLOWERS 40) FIG. 508. — Catasetum tridentatum. A section of the flower: (ao) anther case; (/>) pollen masses; (rf) viscid disc; (&) band connecting pollen-masses with disc; (an) one of the antennae ; (r) rostellum. nectary varies in different plants, and bears, as a rule, the most evident relation to the pollinating of the flower. In the Japan Lily (Lilium speciosum) the narrow grooves at the bases of the perianth form the nectary ; and this is also the case in the Martagon Lily (L. martagori), though here the nectary is more complicated in structure. The grooves (which are deeper than the grooves in the Japan Lily) are bordered by stiff hairs which rise up and arch over to form a tube, through which the nectar must be sucked, so that only long-tongued insects can get at it. In the Garden Nasturtium (Tropceolum majus) the sepaline spur of the calyx is the nectary ; while in the Larkspur (Delphinium, fig. 480) and some closely allied species, the hollow petaline spur secretes the nectar. The two upper petals of Delphinium datum, for example, lie close together so as to form a hollow cone, at the end of which is the nectar ; whilst the spur, beside serving as a guide to the sucking- tubes of bees (the flower's chief pollinators) prohibits by its length the access of insects with shorter tongues. In the Crowfoot family (Ranunculus) the nectar is protected by small scales at the base of the petals — one scale to each petal— as may be seen in the Buttercup (R. acrisj fig. 479, and R. bulbosus) ; while in the Common Barberry (Berberis mdyaris, figs. 479 and 602) — of which more hereafter — each of the petaline iiec- FlG 50^_Cata8etum tridentatum. taries IS double. They differ The flower in the act of expelling the pollinium. 410 HUTCHINSON'S POPULAR BOTANY also from the nectaries of Ranunculus in being thick and fleshy. In the Helle- bores the petals are con- verted into little green vases, which are filled with nectar. In the Violet and Pansy (Viola] tjie correlation be- tween the nectaries and the other organs of the flower is extremely interesting. FIG. 510. — FLOWER OF YUCCA (Yucca recurva). The intricate arrangement of the several parts is a little baffling at first, but the drawing (fig. 482) will help to an understanding of the mechanism "tff the flower. The sketch represents a flower laid open to show the two nectar-excreting appendages of the lower stamens, which, it will be noticed, are inserted in the spurred petal. Into this spur the liquid honey drops. The curious globular head of the stigma, with its hollow mouth-like chamber and tongue-shaped flap, is seen peeping above the triangular anthers, which surround the style collar-fashion : while the pear- shaped ovary is completely hidden by the broadened and cohering filaments of the stamens. The FIG. 512. — YUCCA-MOTH GATHERING POLLEN. FIG. 511. — YUCCA-MOTH (Pronuba yuccasella). With ball of pollen (p) held by tentacle (a). drawing also shows one of the two lateral petals, with its tuft of hairs. Both of the lateral petals are furnished with these hairs, which aid the bee in clinging to the flower. In some species of Viola the grooved part of the inferior spurred petal is also fringed with hairs, but they are for collecting pollen. Photo by] [H. Irving. Fio. 513. — YUCCA-PLANT (Yucca gloriosa). This plant is cross-fertilized by insect agency in a manner which makes it one of the wonders of the vegetable world. The process is fully described in a later chapter. 411 412 HUTCHINSON'S POPULAR BOTANY Now, when a bee wants to reach the honey in a flower — say, of Viola tricolor — it must insert its proboscis close under the capitate stigma, and this, as shown in the sketch, lies in the groove of the inferior petal. Into this groove the anthers shed their pollen, either of themselves or when the pistil is shaken by the bee, and hence the insect's proboscis, in passing down the groove to the spurred nectary, gets plentifully dusted with the yellow meal. As the proboscis is withdrawn, it shuts to the "flap-like door of the stigmatic chamber, so that, for the nonce, no pollen can enter that cavity ; but when the bee thrusts its head into the next flower, it leaves some of the precious dust on the upper surface of the flap. In the Alpine Liane (Atragene alpina) the grooved inner surface of the basal half of the stamens forms the nectary. " The pendulous violet flowers," says Hermann Miiller, " only give up their honey to insects which can force asunder the numerous stamens, which are set closely in several whorls," and which, we may add, are held together on the out- si d e by a whorl of stiff, erect, spoon- shaped stami- nodes.* Bees and h u m- ble-bees are * A stami- node is a barren stamen, more or less filiform in shape, placed either within or without the per- fect stamens, but not furnished, like them, with anthers at the apex. H. Miiller calls the stami- nodes of Atra- gene alpina " petals " ; Ker- ner, " leaves " ; Baillon, "stami- nodes." FIG. 514. — Odontoglossum alexandrce. (a) A. spray of flowers ; (6) A single flower ; (c) Pseudo-bulbs and leaves. THE WELCOME OF THE FLOWERS 413 among the few in- sects powerful enough for this work; and, in point of fact, they alone have been observed to pollinate the plant. The nectaries of cruciform flowers (Cruciferse) are usually glandular swellings at the base of stamens, the honey when secreted either remaining in drops upon the glands, or accumu- lating in the spaces between the stamens and pistil and in the sepaline pouches. The Cuckoo-flower (Cardamine praten- sis, fig. 483) — of which Grerarde quaintly says, " it doth bloome in April and Maie, when the cuckoo doth begin to sing her pleasant notes without stam- mering " — is a good example. The nectar glands are the green fleshy cushions at the bases of the two shorter and the two aborted stamens, and the honey secreted by these glands accumulates in the pouched bases of the sepals. " In the young bud all the six anthers are turned towards the pistil, which projects above-them. Before the flower opens the four inner stamens elongate and overtop the stigma, and make a quarter of a revolution outwards, each one towards the small stamen nearest to it ; so that now an insect, in trying to reach the honey of one of the larger glands [those surrounding the bases of the shorter stamens], must rub its head or proboscis against the pollen-bearing surface of one of the taller anthers" (Miiller). FIG. 515. — Vallisneria spiralis. Female plant on the left; male plant on the right. 414 HUTCHINSON'S POPULAR BOTANY FIG. 516. — FLOWER OF NETTLE ( Urtica dioica). The male or staminate flower. In the Pasque-flower (Anemone pulsatilla} we have an instance of stamens metamorphosed into nectaries — or rather of rudimentary sta- mens, with shortened filaments, and glands instead of anthers (fig. 486). In Papilionaceous flowers, like the Pea and Bean, the cohering fertile stamens secrete and store the nectar (figs. 497-499). They form, a tube around the ovary, and the honey is poured into the base of the tube. Very curious are the nectaries of the well-known Petty Spurge (Euphorbia peplus], so common as a garden weed throughout the kingdom (fig. 487). The border of the cup-like involucre is studded with shining, crescent- shaped glands, which are much resorted to by flies, beetles, and other short-lipped insects, on account of the nectar with which the glands are coated. They are, in fact, the nectaries ; and by their prominence and accessibility they compensate for the inconspicuousness of the flowers. There is a nearly allied plant to the Spurges, a species of Dalechampia, which, according to Fritz Miiller, attracts the insects which cross-pollinate it by means of a colourless resin secreted in special glands. This resin is collected by the insects (bees), and used in nest-building. In the Carrot (Daucm\ Elder (Sambuciis), and Ivy (Hedera) the nectary is also conspicuous, lying almost on the surface of the flo.wer. Ovarian nectaries are found in Antirrhinum, Speedwell (Veronica). the Common Comfrey (Symphytum officinale), and other plants. In the Spiked Speedwell (V. spicata, fig. 489) the fleshy base of the ovary secretes the nectar, and the tube of the corolla holds it like a cup. A ring of long stiff hairs at the mouth of the tube shelters the nectar from rain. This is also the case with the Brooklime (V. beccabunga), which is freely visited by insects, particularly flies. The ovarian nectary of Comfrey ffig. 505) is a white annular ridge, and in order to get at it the insect (usually a humble-bee) has to force apart the anthers, which form an inverted cone near the mouth of the tubular corolla. This releases the pollen, which falls upon the insect, and in due course is transferred to another flower. Other nectaries are sometimes found on the foliar parts of plants, at a considerable distance from the flowers. " It is always pleasant," says a writer in Nature, 1893, " to FIG. 517. — FLOWERS OF VALLISNERTA. (a) Female flower ; (It) bud of male flower ; (r) male flower open. rf 5 /' 5Q >1 gll 415 416 HUTCHINSON'S POPULAR BOTANY hear the contented hum of the bees amongst the young Laurel leaves [of Cerasus lusitanica] ; for with no ulterior ends of their own the prosaic green bushes regale their friends with the sweets secreted by the yellow glands at the bases of their leaves, and, whatever may be said to the contrary, afford a triumphant proof that plants are not exclusively selfish and utili- tarian, as we in our half- knowledge are sometimes apt to imagine." Certain species of Prunus (e.g. the Cherry, P. cerasus) produce nectaries in the form of small red glandular swellings on their leaf-stalks (fig. 489), though the receptacular tubes of the flowers also secrete honey. The Broad Bean, again (Vicia faba), has nectaries on its stipules (fig. 490) ; so have the Vetch ( V. saliva} and the Scabrous Balsam (Impatiens tricornis). These secretory glands appear to be an ingenious device for enlisting the services of ants. It is probable that the writer in Nature just quoted would have modified his statement had he inquired a little further. The truth is that the provision of these nectar-glands on the foliage of plants, so far from being evidence of the plants' philanthropy, is like much that passes for the same virtue in our species— dictated by strict business -considerations. Instead of causing a net drain upon the capital, it yields .Photo by] [E. Step. FIG. 519. — HAZEL FLOWERS (Corylus avellana). The long, swinging catkins consist of male flowers only. Th e female flowers •are bud-like, with crimson threads (stigmas) protruding from the top. These later develop into the familiar Hazel-nuts. BLUE VANDA tV>n,M bottom ; in doing this it jostles and lets iPIL off the springs, and receives upon the under ^V^"^ side of its body and its legs successive charges of pollen. Flying to another blossom, it brings its pollen-dusted body against the stigma, and commonly revolv- ing on it as if on a pivot while it sucks the nectar in the bottom of the flower-cap, liberates the ten bowed stamens, and receives fresh charges of pollen from that flower while fertilizing it with the preceding one." If flowers of Kalmia are protected from insects (the experiment was tried by Mr. Beal with coverings of fine gauze), they wither, drop off, and set no seed ; the reason being that no stamen gets liberated of itself while fit for action (figs. 503, 504). A curious method of clamping the pollen-masses (pollinia) of flowers to the feet of insects is to be noticed in the Asclepiads, and has been dis- tinguished as clip mechanism. In Asclepias cornuti, for example, the connective of each pair of pollinia is a hard substance " capable of holding FIG. 533. — SPOTTED OKCHIS. A flower, partly in section, visited by bee. In pushing its tongue down the spur, its head comes in contact with the pollen-masses and brings them away, as shown below. Photo by}} FIG. 534. — GOODYEB'S OECHIS (Qoodyera repens). A. rare plant of northern Pinewoods, superficially resembling Lady's-tresses, though actually very different. EUKOPE, SIBERIA, HIMALAYA, NORTH AMERICA. 431 432 HUTCHINSON'S POPULAE BOTANY i * %>., FIG. 535. — DWARF ORCHIS (Orchis ustulata). [E. Step. A diminute species of dry pastures and downs. The flowers are only a third of an inch in their longest measurement. The arrangements of the flower are similar to those of the Spotted Orchis. any small delicate object by gripping it like a clip " (fig. 506) ; and these clips are so disposed in the flower that when an insect visits it for nectar a foot is pretty sure to get caught by one of them. On trying to free itself the insect brings away the pollinia, which then, by a remarkable twisting of the ligulate strands which connect them with the clip, are brought close together. This facilitates their insertion by the insect in the stigmatic chamber of a new flower, where, by a breaking of the strands, the leg and its burden part company. The clips, however, remain attached to the insect ; and wasps and flies have been caught with as many as eight of these vegetable pincers fastened to a single foot. The Brazilian Asclepiad, Araujia albens (ljhysianthus albens of gardeners) has acquired an evil reputation outside its own country and been nicknamed the " cruel plant," for causes connected with its floral mechanism. In Brazil the cross-pollination of its tubular flowers is effected chiefly by humble-bees, which find no difficulty in pulling themselves free when their feet get caught in the slit-like notches that guard the way to the pollinia; arid thus the pollen-masses get carried off to new flowers. In other parts, however, as Michigan, Italy, and the Orange Free State, the plant is visited in large numbers by moths, whose complete ignorance of the mechanism of the SOME PLANT MARRIAGES 433 flowers becomes their ruin. Thrusting their probosces in the slits to get at the nectar, they are held fast, and all their struggles to liberate themselves only fix them tighter. With their heads in the tubes of the corollas, and their bodies and wings projecting, they die a lingering death. We come now to the Orchids. The parts of an Orchid flower have been described in the previous chapter, where also the pollination of a British orchid, the Common Twayblade (Listera ovata), is briefly described. Perhaps it will not be taken amiss if, before going farther afield, we direct attention to another British species — the Spotted Orchis (Orchis maculata) — the pollina- tion of which differs from that of the Twayblade in some important parti- culars. It will be seen (fig. 533) that the sepals and two upper petals of this flower arch over the pollinia and rostel- lum, and that the inferior petal or lip affords an excellent landing-stage for visitors. This petal is prolonged back- wards into a hollow spur, which takes the place of a nectary ; for though it secretes no free honey, its delicate and succulent tissue is much prized by flies and bees. The pouched rostellum, which contains a brownish and viscid matter, projects into the mouth of the spur and also overhangs the two stig- matic surfaces ; while the only perfect anther (the others are mere rudiments) stands immediately above it. Now, an insect visiting the flower and dipping its head into the spur, necessarily strikes against the rostellum. In so doing the pouch gets ruptured, and as the ruptured membrane curls back, it brings into view two viscid discs or balls in close connection with the caudi- cles (stalks) of the pollinia. These n—10 Photo by] [E. Step. FIG. 536. — GREEN-MAN ORCHIS (Aceras anthropophora ) . The divisions of the long lip are supposed to represent the human figure, the arched sepals forming the head. The arrangements are much like those of the Purple Orchis. 434 HUTCHINSON'S POPULAR BOTANY instantly adhere to the intruding object, and when the insect withdraws its head, the two pollinia are seen to be sticking up upon it like a pair of clubbed horns. Moreover, the cement, which has remained viscid under its membranous covering perhaps for many hours, now hardens with great rapidity — a wonderful and indispensable provision, for were the pollinia to fall sideways or backwards, their usefulness for purposes of cross-fertiliza- tion would be at an end. Never- theless, at their present angle they are equally useless, for, on visiting another flower, what can happen but that the insect will push them back into their old position ? This danger is obviated by a beautiful contrivance, which Darwin thus explains : " Though the viscid sur- face remains immovably affixed, the apparently insignificant and minute disc of membrane to which the caudicle adheres is endowed with a remarkable power of contraction . . . which causes the pollinium to sweep through about ninety degrees, al- ways in one direction — viz., towards the apex of the proboscis — in the course on an average of thirty seconds. . . . Now, after this move- ment and interval of time (which would allow the insect to fly to another flower) . . . the thick end of the pollinium is exactly in position to strike the stigmatic surface." Surely if evidence were wanted for the argument of Design in Nature, you have it here ! We may add that Darwin is speaking of the Purple Orchis (0. mascula) ; but his remarks apply equally to the Spotted Orchis.* The plants are closely related, and the manner of their pollination is the same in all essentials ; indeed, throughout the genus Orchis, but little variation of the organs will be found. The genus Orchis is not the only group of orchideous plants containing species which are unprovided with true nectaries. The wonderful Catasetum * Indeed, to two other British Orchids— viz., the Green-winged Orchis (0. morio) and the Marsh Orchis (0. latifolia). Photo by] IE. Step. FIG. 537. — PURPLE ORCHIS (Orchis mascula). An early spring Orchis with red-purple flowers whose arrange- ments for pollination are very similar to those of the Spotted Orchis. FIG. 538. — FRAGRANT ORCHIS (Habenaria conopsea). A plant of the downs and dry pastures, with a spike of very fragrant bright rose-red or purple flowfrs, which have a long and slender spur. The spur is half filled with nectar and specially adapted to the long tongues of butterflies and moths. The litter appear to be attracted chiefly to the form with white flowers. EUROPE, N. and W. ASIA. 435 436 HUTCHINSON'S POPULAR BOTANY tridentatum and its female, the Monachanthus,* are further examples (fig. 507), The cup or labdlum — which in other species is usually the nectar receptacle — is singularly inverted in the varieties specified, and thus is altogether precluded from fulfilling that purpose. Yet, since the sexes stand on separate plants, insects must be attracted to the flowers in order to secure pollination ; and insects, like beings of a higher order, will not work except for reward. Dar- win was the first to point out that the labellum itself, which in these varieties is thick and fleshy and of " a pleasant nutritious taste," probably affords food to its insect visitors, and thus answers the pur- pose of nectar, just as do the tubes in Orchis maculatci and 0. mascula. His surmises have been abundantly verified. Darwin regarded the genus Catasetum as " the most remark- able of all Orchids." They possess the extraordinary power of forcibly expelling their pollinia when a certain part of the flower — the horns or anteniice of the column (fig. 508, an)— is touched; and therein lies their extraordinary interest. Observe how the band or pedicel of the pollinium (6), which connects the disc (d) with the pollen-masses (p\ is curved about the projecting rostellum. This pedicel is in a high state of tension. When either of the taper- ^^^^^^^mi^^^fmsaaa^mammfm^^f^mmm Phol [E. Step. FIG. 539. — GREEN-WINGED ORCHIS (Orchis morio). A plant frequently mistaken for the Purple Orchis, but distin- guished at a glance by the parallel green lines along the sepals, and absence of purple spot* from the leave?. * So dissimilar is the female flower of Catasetum tridentatum from the male that it was long regarded as belonging to a distinct genus, Monachanthus, and styled M. viridis. Singularly enough, C. tridentatum also bears hermaphrodite flowers, which differ no less in appearance from the male and female forms than do those from one another. Hence the plants producing them were classed with a third genus, Myanthus, under the specific name barbatus. But a plant was discovered bearing flowers of the three supposed genera on one spike, and so the true state of things was recognised, and revision of names made accordingly. SOME PLANT MARRIAGES 437 ing sensitive projections or antennae is touched (and bees visiting the flower to gnaw at the labellum inevitably come in contact with it), " the edges of the upper membrane of the disc," says Darwin, '• which are continuously united to the surrounding surface, instantaneously rupture, and the disc is set free. The highly elastic pedicel then instantly flirts the heavy disc out of the stigmatic chamber with such force that the whole pollinium is ejected, bring- ing away with it the two balls of pollen, and tearing the loosely attached spike-like anther from the top of the column (fig. 509). The pollinium is always ejected with its viscid disc foremost." The force of the discharge will sometimes send the pollinium a dis- tance of two or three feet. One of the attendants at Kew Gardens told the writer that he was once severely rated by a lady who had been struck in the face by the pollinium of Catasetum saccatum, and had come to him with the disc yet sticking to her cheek ! Such experiences, are not uncommon. Lord Avebury saw a flower of Catasetum callosum precipitate its pollinium a distance of three feet, when it hit a pane of glass and adhered to it. " From the large size of the flower, more especially of the viscid disc, and from its wonderful power of adhesion," says Darwin, " we may safely infer that the flowers are visited by large insects. The viscid matter sticks so firmly when it sets hard, and the pedicel is so strong (though very thin and only one-twentieth of an inch in breadth at the hinge) that to my surprise it supported for a few seconds a weight of 1,262 grains — that is, nearly three ounces ; and it supported for a considerable time a slightly less weight." Needless to say, no effort which an insect thus encumbered could exert would remove the disc and pedicel : " but the Pholo by] \_E. Step. FIG. 540. — BiRb's-NEST ORCHIS (Neottia nidus-avis). An Orchis without leaves and with yellow-brown tlowens. The roots take the form of a mass of thick fibres whose interlac- ing is supposed to look like a bird's nest. 438 HUTCHINSON'S POPULAR BOTANY caudicles are ruptured without much difficulty, and thus the balls of pollen would be left on the viscid stigmatic surface of a female flower.'' In striking contrast to the Catasetums are those Orchids which secrete great quantities of nectar, like Coryanthes. The sweet iiitid secreted by the strange-looking horns of Cury- anthes macrantha, for example, drips so plenteonsly into the bucket- shaped portion, of the labellum at the period of flowering that it half fills the bucket — indeed, would quite fill it, were it not that the receptacle is provided with an overflow spout ! Above the bucket is a hollow chamber, walled and ceiled with fleshy ridges and pro- vided with two side entrances. " The most ingenious man," says Darwin, "if he had not witnessed what takes place, would never have imagined what purpose all these parts serve. But Dr. Criiger saw crowds of large humble-bees visiting the gigantic flowers of this orchid — not in order to suck nectar, but to gnaw off the ridges within the chamber above the bucket; in doing this they fre- quently pushed each other into the bucket, and their wings being thus wetted, they could not iiy away, but were compelled to crawl out through a passage formed by the spout or overflow. Dr. Criiger saw a continual procession of bees thus crawling out of their invol- untary bath. The passage is nar- row, and is roofed over by a column, so that a bee, in forcing its way out, first rubs its back against the viscid stigma, and then against The pollen-masses are thus glued Photo by] IE. Step. FIG. 541. — PYRAMIDAL ORCHIS (Orchis pyramidalis). Somewhat like the Fragrant Orchis, but with larger flowtrs. The flower-spike is at lirst pyramidal. The long spur contains no ^nectar, and visiting insects have to suck at the lining membrane. the viscid glands of the pollen-masses, to the back of the bee which first happens to crawl out through the passage of a lately expanded flower, and are thus carried away. When the bee, thus provided, flies to another flower, or to the same flower a second time, and Photo by] \J- "• FIG. 542. — YUCCA PLANT (Yucca gloriosa). The fertilization of the Yucca— fully described in the following pages— is one of the wonders of plant life. 440 HUTCHINSON'S POPULAR BOTANY is pushed by its comrades into the bucket, and then crawls out by the passage, the pollen-mass necessarily first comes into contact with the viscid stigma, and adheres to it, and the flower is fertilized. Now at last we see the full use of every part of the flower — of the water-secreting horns, of the bucket half full of water, which prevents the bees from flying away, and forces them to fall out through the spout, and rub against the properly placed viscid pollen-masses and the viscid stigma." A gardener of long experience in Orchid culture informs us that Stanhopea haselojji, which belongs to an allied genus, is cross-pollin- ated in the same way as Coryanthes, save that the half-drowned bees fall out of the bucket, and strike against the pollinium in falling. The subject of insect-pollina- tion is inexhaustible, yet even the slightest sketch would be inadequate that failed to contain some refer- ence to the fertilization of the Yucca-plant. It is nearly forty years since Professor C. V. Riley, of» Missouri, first announced the method of pollination of the Yuccas by a little white moth, which he christened Pronuba yuc- casella. Since that time much has been written on the subject, and in 1892 Dr. Riley published a valu- able monograph on Yucca pollina- tion, from which we have gleaned most of the particulars given below. The monograph, which extends to A. little-known Orchi.1 with preen dowers, which secrete no nectai— it has no spur— but gives off the odour of musk in the evening for the attraction of small beetles. Photo by-\ FIG. 543. — MUSK ORCHIS (Herminium monorchis). sixty large octavo pages, and is fully illustrated, is included in the third annual report of the Missouri Botanical Garden. The Yuccas are a very interesting genus of plants of the lily family, comprising numerous species and even sub-genera, all characterized by anthers not reaching anywhere near the stigma ; so that fertilization unaided can take place only by the merest accident. These plants, in fact, SOME PLANT MARRIAGES 441 FIG. 544. — MARSH-CALLA (Calla palustris). A. marsh snail is seen to be climbing t'.ie stem. Snails have been observed to pollinate the flowers. depend for their very existence on certain little white moths, belonging to the im- portant group Tinseina, and to the genus Pronuba. Thus the Yuccas affords an in- stance— apparently the only known instance — of plants which are dependent on a single species for pollination. The common Yuccas of the United States are forms of Yucca falamentosa, and their white-winged pollinator is the commoner Yucca moth, Pronuba yuccasella (fig. 512). During the daytime this moth, either singly or in pairs, may be found resting with folded wings within the half-closed flowers. After sundown it is to be seen flitting swiftly from plant to plant and flower to flower ; the dusky nature of the hind wings and of the under surface of the front wings almost completely off-setting and neutralizing, when in motion, the upper silvery whiteness of the latter. This is the male insect. The female is busily at work most of the time in the flowers ; for on her devolves a double duty, which leaves no leisure for these nocturnal flittings. As a part of the maternal task of continuing her race, she must act as foster- mother to the plant in order to ensure a proper supply of food to her larvae, which, as we shall presently see, feed on its seeds. Her activity begins soon after dark, and consists at first in assiduously collecting a load of pollen. She may be seen running to the top of one of the stamens, and bending her head down over the anther, stretching her maxillary tentacles, which are wonderfully modified for the purpose, to the fullest extent ; and using her palpi to scrape the pollen from the anthers towards the tentacles. After gathering a sufficient supply, and shaping it into a pellet twice or thrice the size of her head, she sets off for another flower, leaving the despoiled blossom to be pollinated by some other individual of her race. On entering the new flower, she takes up a favourable position, and after resting motionless for a short time, plunges her lance-like ovi- positor into the soft tissue of the pistil, and conducts her first egg to its destina- tion. Mark what follows. No sooner is the ovipositor withdrawn than the moth -runs up to the top of the pistil, thrusts the pollen into the stigmatic funnel, and W FIG. 545. — MARSH-CALLA (Calla palustris). A single flower removed from the ?padix and enlarged. 442 HUTCHINSON'S POPULAR BOTANY rams it down effectually with a to-and-fro motion of her head. If. as is commonly the case, another egg is deposited in the same pistil, and after that a third, each act of oviposition is succeeded by a fresh act of pollination ; but on each occasion a different notch of the style is selected, and thus a supply is ensured for the ovules in each carpel. How perfectly the insect does its work may be gathered from the fact that artificial attempts to cross-fertilize the Yuccas by means of brush-pollination are rarely, if ever, successful. The larva hatches in about a week, and at first appears to live on the degenerate and swollen ovules ; but finally it enters one that is developing. In this state it undergoes three different moults, its colour meanwhile changing from a translucent white to a rosy hue ; and with the ripening of the seeds, the larva attains its maturity. Just about the time the fruits are hardening and ready to dehisce, and the seeds are already coloured, the maggot bores a passage through the pod, makes its way to earth, and, tunnelling several inches below the surface, spins in its under- ground fastness a tough silken cocoon intermixed with the soil. In this condition it remains during the autumn, winter, and spring months, and only assumes the chrysalis state a few days before the blooming of the Yuccas. The FIG. 546. — BALSAM (Impatiens). r r • i -,i chrysalis is armed with spines on The flowers are adapted to the visits of humble-bees. At first ,1 i ^ i i i i the stamens mask the pistil and stand in the entrance to the tHe Jieaa and DaCK. by means OI flower. Later the pistil occupies this position and receives v • i •, i -j. i pollen brought from a younger flower. Which it WOrkS its Way to the SUr- face, and in due time issues forth a perfect insect; henceforth to live its little life above ground, and, in conjunction with some chosen companion of the other sex, to carry on the useful work which its parents have carried on before it. Of animals outside the great class Insecta which aid in bringing the reproductive elements of plants together, the chief are snails and birds. Delpino, indeed, divides the plants fertilized by animals into three groups : I. Ornithophilce, or bird-lovers ; II. Entomophilce, or insect-lovers ; and III. Malacophilce, or snail-lovers. Groups I. and III. remain to be spoken of. The plants fertilized by the agency of snails are comparatively few in number. The Marsh-calla or Snake-root (Calla palustris, figs. 544, 545) may serve as an example; though its chief pollinators are carrion-loving flies, which are attracted to the fiowers by their offensive smell. Pond- snails, however, crawl up the partially submerged stem to the spadix, receive pollen from the anthers of the lower ring of flowers, and, continuing their journey, pollinate the female flowers higher up. Photo by] [F. C. Taylor. FIG. 547. — Alocasia spectabilis. An herbaceous plant belonging to the extensive order Aroideie. The large radical leaves of this plant are beautifully variegated. In one species the flowers have been observed to be pollinated by snails. 443 444 HUTCHINSON'S POPULAR BOTANY In Alocasia odora, a plant be- longing to the same order (Aroidece), snails enter the spathe by a narrow opening, lose their way when inside, and in their purblind efforts to re- gain the entrance, dust themselves with pollen, which they convey to the stigmas of younger plants. Delpino was of opinion that the snails " are poisoned by an irritant secretion within the chamber of the spathe, and are so prevented from devouring the flowers" after cross- pollination has been effected. The same naturalist has recorded obser- vations on the snail-pollination of Rhodea japonica and of Cypripedium caudatum, and states of the former that the flowers which proved fer- tile were always those over which snails had crawled. Then as to birds. In tropical, and even in temperate America, sun-birds and humming-birds are the welcome guests of many flowers. " Chiefly in the months of July and August," says Waterton, " the tree called Bois Immortel, very common in Demerara, bears abundance of red blossom, which stays on the tree for some weeks ; then it is that most of the species of humming-birds are very plentiful. The wild red Sage [? Salvia coccinea] is also their favourite shrub, and they buzz like bees round the blossoms of the Wallaba-tree [Eperua falcata]. Indeed, there is soarce a flower in the interior, or on the sea coast, but what receives frequent visits from one or other of the species." It will be noticed that the plants named by Waterton in the above passage all bear red flowers : and many naturalists have pointed out that humming-birds appear to have a penchant for scarlet. Fortunately — both for visitors and visited, for bird guests and plant hosts — scarlet blossoms are plentiful in the primeval forests of Central America, where humming- birds chiefly have their home. In those densely vegetated regions may be seen the flaunting reds of the lianes and epiphytes of many widely differing genera, with the dazzling scarlets of Begonias and Fuchsias, of Sages and Lobelias, of Browneas and Erythrinas, the very construction of whose blossoms in not a few instances forbids their being rifled by FIG. 548. — SECTION OF LAPAGERIA. The nectary is at the base of the flower, that is, the upper part as it hangs. SOME PLANT MARRIAGES 445 insects. Numbers of such flowers take a lateral direction, and are un- provided with landing-stages ; for humming-birds never alight when feeding, but sip the nectar as they hover with widespread wings at the mouths of the flowers. The absence of ridges, knobs, and fringes, which serve so useful a purpose in insect-pollinated flowers, is also to be remarked. Darwin, in his Cross and Self-fertilization of Plants, gives an interesting summary of the cases of bird-pollination known to himself, which it will be useful to quote. " In South Brazil," he says, " humming-birds fertilize the various species of Abutilon, which are sterile without their aid. Long- beaked humming-birds visit the flowers of Brugmansia, whilst some of the short-beaked species often penetrate its large corolla in order to obtain the nectar in an illegitimate manner, in the same way as do bees in all parts of the world. It appears, indeed, that the beaks of humming-birds are specially adapted to the various kinds of flowers which they visit ; on the Cordillera they suck the Salvics, and lacerate the flowers of the Tacsonice • and in Nicaragua Mr. Belt saw them sucking the flowers of Marcgravia and Erythrina, and thus they carried pollen from flower to flower. In North America they are said to frequent the flowers of Impatiens. I may add that I often saw in Chili a Mimuswith its head yellow with pollen from, FIG. 549. — YARROW (Achillea ptarmica). A small Composite that is specially attractive to the little bees of the genus Prosopis. 446 HUTCHINSON'S POPULAR BOTANY as I believe, a Cassia. I have been assured that at the Cape of Good Hope, Strelitzia is fertilized by the Nectarinidse [the Sun-birds]. There can hardly be a doubt that many Australian flowers are fertilized by the many honey- sucking birds of that country. Mr. Wallace remarks that he has ' often observed the beaks and faces of the brush-tongued lories of the Moluccas covered with pollen.' In New Zealand, many specimens of the Anthornis melanura had their heads covered with pollen from the flowers of an endemic species of Fuchsia." A later observer. Pro- fessor W. Trelease. of the Missouri Botanical Garden, gives a yet longer list, and states that an Alabama planter once laughingly said to him: " You'll have to note every conspicuous flower if you want a full list of those visited by the humming- birds." On several occa- sions the professor watched the ruby-throated hum- ming-bird extracting nectar from the glands at the base L»_ I // I f.y •• jfefc^M; °^ ^ie inv°lucre in cotton- flowers (Gossypiuiri) ; and he found that humming-birds were largely — it' not exclu- sively—used in the crossing of Malvaviscus, a scarlet- flowering genus of tropical shrubs. The observations of a still younger botanist, Mr. William Sugden, of Michi- gan, are equally worthy of attention. Mr. Sugden tied bags over the flower-buds of Impatiens fulva, and also over flowers which had opened, but before the stamens (whose anthers in the first stage form a covering over the pistil) had disappeared. In neither case were good seeds produced, though artificial crossing under similar conditions was suc- cessful. Flowers of the same species, unconfined in this manner, but divested of their petals, set no seed whatever; and this was also the result Ptio'o 6y] [E. Step. FIG. 550. — WHITE CAMPION (Lychnis vespertina). Its white flowers open in the evening, when it becomes sweet-scented for the attraction of night-Hying moths. Nectar is secreted by the base of the ovary. In the daytime the flowers look faded or dead. Photo by] IE. Step. FIG. 551. — HEATHER OK LING (Calluna vulgaris). The most conspicuous part of the flower is the rosy calyx, the corolla being quite small. The leaves are very minute and like overlapping scales. They are specially adapted to resist cold. EUROPE, \v. SIBERIA, AZORES, GREENLAND, N. AMERICA. 447 448 HUTCHINSON'S POPULAR BOTANY even when the nectar-gland only was removed. Mr. Sugden noticed also that black bees, which visited the free and unmutilated flowers in large numbers, hardly ever touched an anther or pistil, so that they were of no use as pollinating agents. The visits of wild bees and the common honey-bee were equally profitless to the flowers ; and even when a humble- bee hit pollen in its plunges to get at the nec- tar, it left the plant after trying a single flower. "With humming-birds the case was quite different. Every time one of these little creatures thrust his arrowy beak into a flower of the first stage, his head would strike the anthers and become dusted with pollen. On visiting a flower in the second stage — i.e. after the withering of the crown of anthers — the bird's head would come in contact with the exposed stigma, with the inevitable result that some of the pollen would be left upon it. Of the plants which lay themselves out for cross- fertilization, but which do not invite the co-operation of small animals, some em- ploy water as their agent, and others the wind. Ex- ternal aid for the purpose in question may therefore be of three kinds, and the plants which require those agencies to bring their re- productive elements to- gether may be grouped under one or another of the following heads : ZoophUce, or animal-lovers ; Hydrophttce, or water-lovers ; and Anemophilce, or wind-lovers. Wind- and water-pollinated plants are rigid economists, except in the matter of pollen.. They have no attractive odours, no bright petals, no nectar. Birds and insects may be allured by these things, but not so wind Photo by] FIG. 552. — ASPEN (Populus tremula). IE. Step. The simple (lowers are borne i to allow pollination by the lea long catkins, which appear be/ore the leaves es. Those shown in ttie photo are the male catkins. CKRYAXTKS' ODOXTOGI.OT (Odo>ifo(ilo*tum cercautetn). The Odontoglots are a beautiful genus of epiphytal Orchids inhabiting the tropical regions of America. Over a hunc species are known. Cervantes' Odontoglot is a native of Mexico. Each pseudo-bulb produces a single leaf and a si of from three to five rosy-lilac flowers. Natural size. SOME PLANT MARRIAGES 449 and water, which, having no senses to be appealed to, would be unaffected by colour, sweets, or scent. Yet being wasteful carriers, these agents require abundance of pollen ; and, if water is to be the vehicle of trans- mission, the pollen must be either lighter than the water or of like specific gravity : if wind be the agent, the pollen must be smooth, light, and incoherent. In the vast majority of cases these conditions are found to be wonderfully fulfilled. Of hydrophilous plants some are adapted for fertilization under the water: and these are provided with a pollen of like speci- fic gravity to the surrounding fluid ; others are adapted for fertilization at the surface, and the pollen of these — unless borne upon a floating raft — is specifically lighter than the water. The Grass-wracks (Zoster a] are re- markable for pro- ducing a pollen the grains of which do not, like the- gener- ality of pollen- grains, burst in water. Moreover. the grains assume the form of elon- gated cylindrical tubes on quitting the anthers, which greatly facilitates their conveyance through the water to the threadlike stigma of the flowers. Something almost analogous takes place in certain cryptogamic plants — notably the Floridece or Red Seaweeds — where the male cells are neither motile nor provided with hairs, but are borne about passively by currents of water till they attach themselves to the slender projecting terminal cells of the female organs. The Sea Ruppia or Tassel-grass (R. maritima), closely allied to Zostera, is a widely distributed plant adapted for pollination on the surface of water. At the period of maturity the submerged flower-stalk lengthens, and the ii—ll Photo by] [E. Step. FIG. 553. — SCOTS PINK (Pinus sylvestris). The male flowers [are here shown spirally arranged in spikes and a large number of spikes forming a cluster. Tne female (lowers are borne on the same tree, but on separate branches. 450 HUTCHINSON'S POPULAR BOTANY plant lifts its head above the marsh or salt-pool which it inhabits. Lengthen- ing continues until the object is attained, but thereupon ceases, no matter what the depth or shallowness of the water. The Rev. Gerard E. Smith. a botanist well acquainted with the plant, has thus sketched the process : " The anthers are vesicular and buoyant : as they swell and become mature, the membranous sheath enclosing them is distended, and the whole is brought to the sur- face of the water. The flower-stalks are rapidly lengthened, the flowers quit the sheath, which then becomes a bladder, and aids the eleva- tion of the spike an inch above the water. Presentl}* the anthers burst, the vesicle loses its- buoyancy, and the flower-stalks, bear- ing the fertilized stigma, sinks within the bosom of the parent plant." It will be noticed that the flowers both of Tassel-grass and Zostera are small and inconspicuous,, and possess neither calyx nor corolla. Large blossoms and Photo by-} [E. step. bright colours would FIG. 554. — SCOTS PINE (Pinus sylvestris). be useless to plants which depend on water for the distri- bution of their pollen, just as they are to the wind-pollinated forest trees. Doubtless the most curious of hydrophilous plants is the Italian Eel-grass (Vallisneria spiralis), which is also one of the greatest marvels of the vegetable world. It is distributed throughout Southern Europe, and grows in still water. Our illustration (fig. 515) shows both the male and female plants, with their strap-shaped leaves and flowers in various stages ; the male plant is on the right, the female on the left. The pistillate (i.e. female) The female flowers are ienal; the tips of the shoots. The cones are soon formed, but seeds do not ripen until the second year. 451 452 HUTCHINSON'S POPULAR BOTANY flowers are borne on long stalks (fig. 517, «), each of which, whilst the stigmas are maturing, is enveloped in a kind of bladder. The staminal flowers are similarly invested, but they grow in thick clusters, and one sheaf suffices for all the individuals of a cluster. Each of these male inflorescences is borne on a short rachis (fig. 517, 6, c), which remains short to the end of the chapter ; but at a certain stage the pedicels of the female flowers lengthen to an extraordinary extent, and presently reach the surface of the water. The floral sheaths in the plants of both sexes meanwhile fall apart, and everything betokens readiness for nuptial celebrations. But now an interesting problem arises. While the female flowers, held by their thread-like pedicels, are floating restfully on the bosom of the water, the male flowers are anchored far down' below by their diminutive stalks to the short axes. How are the sexes to bej-brought together? The problem is solved in a very wonderful, and, at the same time, a very simple man- ner. The submerged male flower-buds de- tach themselves spontaneously from their axes, and, being lighter than the water, ascend to the surface. Here they drift about for a while ; then open, and, twisting back their three sepals in an ingenious man- ner, so as to make a float, bring into view the two perfect sta- mens, which now stand well out of the water like a pair of snail's horns. These miniature floats, as Kerner beautifully remarks, "are blown hither and thither by the wind, and accu- mulate in the neigh- bourhood of fixed IB. Step. FIG. 556. — OAK (Quercus robur). These are the male flowers in long, loose catkins. The female flowers— borne by the same tree — are like little buds, and not so noticeable. SOME PLANT MARRIAGES 453 bodies, especially in their recesses, where they rest like ships in harbour. When the little craft hap- pens to get stranded in the recesses of a female Vallisneria flower, they adhere to the trilobed stig- ma, and some of the pollen-cells are sure to be left sticking to the fringes on the margins of the stig- matic surf ace s." Pollination having been thus effected, the pedicel of the fertilized flower con- tracts spirally and the ovary descends to the bottom of the water to perfect its seeds. We come now to the anemophilous or wind-pollinated plants. Most of our forest trees, and the grasses, are exam- ples of this group. AVind is far more ex- tensively employed as a pollen-carrier than water, but, is not so busy an agent as insects. Flowers which lay themselves out for wind-pollination are characterized by abundance of smooth and dusty pollen ; by stigmas specially adapted for catching and retaining it; and, as we have seen, by an absence of bright-coloured floral envelopes, perfumes, and honey. " The amount of pollen produced by anemophilous plants," says Darwin, " and the distance to which it is often transported by the wind are both surprisingly great. Mr. Hassal found that the weight of pollen produced by a single plant of the Bulrush (Typha) was 144 grains. Bucketfuls of pollen, chiefly of (Joniferce and Graminete, have been swept off the decks of vessels near E. Step. FIG. 557. — COTTON-GRASS (Eriophorum polystachion). The Co) ton-grasses are Sedge-like plants that cover vast areas of boggy moorland. The " cotton " really consists of delicate bristles which represent the petals of other flowers. 454 HUTCHINSON'S POPULAR BOTANY FIG. 558. — POL- LEN-GRAINS OF GREAT PANI- CLED SEDGE (Ga- rex paniculata). the North American shore ; and Mr. Riley has seen the ground near St. Louis, in Missouri, covered with pollen, as if sprinkled with sulphur : and there was good reason to believe that this had been transported from the pine-forests at least 400 miles to the south. Kerner has seen the snow- fields on the higher Alps similarly dusted ; and Mr. Blackley found numerous pollen-grains, in one instance 1.200, adher- ing to sticky slides, which were sent up to a height of from 500 to 1,000 feet by means of a kite, and then uncovered by a special mechanism." A shower of pollen which fell in Inverness-shire in the year 1858 (our authority is Professor Ainsworth Davis) covered the ground to a depth of half an inch. Of the three great classes into which the Flowering Plants are divided — namely, Monocotyledons, Dicotyledons, and Gymnosperms — one class, the last named, is entirely composed of wind-pollinated plants. The Gymno- sperms derive their names from the fact that their ovules are not contained in an ovary — they are naked. The ilowers, which are unisexual and without calyx or corolla, would stand but a p >or chance of perfecting their seeds were it not for the kindly offices of the wind. The Scots Pine (Pinus sylvestris) offers a good example of the wind- pollinated gymnosperm. Its inflorescences are cones, the male cones, which grow in clusters, being much smaller than the female. In the month of June the anthers open, and discharge their ivinged pollen, which is furnished with microscopic air-bladders (fig. 495), into the grooved backs of the membranous anther-scales, where it lies ready for the breeze to scatter it. Meanwhile the female cones get ready for the "sulphur shower," and being unprovided with any stigma or subsidiary stigmatic appendage, the naked ovules exude a viscid substance which holds fast the pollen that falls in their way, and which, as it dries up, draws the pollen through the micropyle into the interior of the ovule. The fertilized ovules do not arrive at maturity— that is, become ripe seeds — for two years ; and hence every female cone may be said to have three periods, which correspond with three distinct stages in the development of the inflores- cence. In the first period the cone is green and small, and is seated on one of the very young shoots ; in the second period (i.e. at the beginning of the second yearj the cone is larger, but still green, and of course the shoot has become older ; in the third period — the cone being now two years older— the scales have become brown and wood}7, and the seeds are ripe. Among the Angiosperms (Dicotyledons and Monocotyledons) the contrivances for FIG. 559. — POLLEN-GRAIN MAGNIFIED, Showing the intine bursting through the extine as the pollen-tube. Photo by} [E. Step. Fip. 560. — GREAT WATER DOCK (Rumex hydrola-pathum). The largest of our species of Docks, growing bv river-sides and attaining a height of five or six feet. The wind- pollinated flowers are minute, but conspicuous by being combined in large panicles, which give it a very handsome , mid striking appear,! n.-e. Its distributi' 455 is restricted to Kurope. 456 HTJTCHINSON'S POPULAR BOTANY wind-pollination are more elaborate than among the Gymnosperms. " The anemophilous angiosperms," says Hermann Miiller, " have for the most part enormously developed stigmas, which project in the form of long tails, brushes, laminae, or discs; their male flowers are very seldom immovable, but are generally easily shaken by the wind, either the axis of the male inflorescence or the peduncle of the male flowers, or the filaments them- selves, being long and pendulous ; in some cases the stamens are explosive, and project all the pollen into the air." We may take as our first example the flowers of the Hazel (Corylus avdlana). Most people are familiar with the long pendulous " lambs' tails," as the children call them, which make their appearance on the Hazel in the autumn, and which, in the South of England, open in January or February. These are the male in- florescences or catkins * (fig. 519). The female inflorescences are the small cone-like growths (strobiles], sometimes rather loosely described as "female catkins," which appear in the axils of the new shoots. The tiny groups of crimson threads project- ing from the tops of the FIG. 561. — HAZEL (Corylus avellana). strobiles are bunches of Abnormal male flowers. A single catkin has branched at half an inch from' its f nrtprl cti rrrn a a TV>o origin and ends in a bunch of twenty-five short catkins. Natural size. " ->rKeCt bllgmaS. anthers open while the hazels are still bare of leaf, and roll out their pollen into the trough-like depressions of the flower's scaly bracts, which retain it " until the tassels are set swinging by a gust of wind." Then the yellow dust, with no foliage to impede it, is blown hither and thither, and the stigmas of a great number of female flowers are sure to get pollinated. That pendulous floivers, no less than pendulous inflorescences, should facilitate the scattering of pollen by the wind goes without the saying. Many species of Rumex, the genus to which our Broad-leaved Dock and Sheep's- * The more technical name for a catkin is an amentum. PhoK, by} [E. Step. SOME PLANT MARRIAGES 457 sorrel (R. obtusifolius and acetosa) belong, are of this kind, and are anemophilous. In the Alpine Dock (R. alpinus) and the Garden Sorrel t'R. scutatus), the anthers are pendulous at the ends of the delicate filaments, and the pollen-dust is shaken out of them in the lightest breeze. Most of the Sor- rels, however, and with them the Grasses, Sedges, Rushes, and Wild Plantains, are em- braced under a far more common va- riety of anemophil- ous flowers — name- ly, the forms with long stamens. In the Rye-plant (Secale cereale), for instance, the essential organs protrude freely from the widely expanded flowers, and cross- pollination is effected on a large scale by the wind. Delpino has some interesting observations on the Ribwort Plantain (Plantago lanceolata} which seem to show that the flowers of this species are in process of develop- ment from an ane- mophilous to an en- tomophilous form. He says : " One form, with a strong and very tall scape, and very broacl white anthers which quiver in the wind, grows in meadows exclusivelv and s anemo- An abnormal fo edges. FIG. 562. — LARGE PLANTAIN (Plantago major). ti the flower- likes bearing inimerc ant, being reproduce large bracts with purple true from seeds. 458 HUTCHINSON'S POPULAR BOTANY philons, for I have never seen it visited by insects. The second form grows on the hills, and has a much shorter scape : it also is essentially anemo- philous. I once saw a species of Halictus on a spike, trying to get pollen ; but the structure of the flower is so unfitted for pollen-collecting, that great part of the 1 y- , pollen fell to the ground without benefiting either the plant or the insect. Finally, the third form is dwarfish and X"*^ ^^"M < / vV"^ " Y^'~ * confinedtothemoun- Y»" vxi~~ V //,*-' ' tains; it has the shortest spike and filaments ; on mea- dows in the Apen- nines at Chiavari I have seen bees in numbers flying from one flower to another of this variety, col- lecting the pollen and performing cross- fertilization. " This, therefore, is a form of Plantago which hangs be- tween the anemo- philous and entomo- philous conditions, and is capable of be- ing fertilized equally well by the wind and by the bees. If the filaments became stiff and coloured, FIG. 563. — COMMON SORREL (Rumex acetosa). on plant formerly used as a salad an:l pot-herb : its juices abounding in o •Oi. The sexes are on separate plant?, and the pollen is carried by the and the pollen-grains adhesive, while the anthers lost their pe- culiar quivering, we should have before us the passage from anemophilous characters, the evolution of an entomophilous from an anemophilous species. ': This hypothetical transition has actually occurred. Plantago media is a form that has become entomophilous ; the filaments have become pink, the anthers are motionless, the pollen-grains have become more [E. Step FIG. 564. — FALSE CYPERUS (Carex pseudocyperus). One of the (inert of our Sedges, growing to a height of about three feet. The stems are three-sided, with rough e Iges. The spikelets take the form of ions.' drooping catkins, two to three inches long. The male spikfU-.s solitary ; the females in clusters of four or five. Wind -pollinated. TKMFERATE REGIONS GENERALLY. 4o9 460 HUTCHINSON'S POPULAR BOTANY aggregated, and it is visited regularly by Bombus terrestris, as I have observed at the same spot (Chiavari) in the Apennines." Explosive forms of anemophilous flowers are met with in the Nettle family (Urticacese) and a few other species. The Great Nettle (£7. dioica. fig. 516) is an excellent example. Here the sexes are on different plants, and the flowers are small, green, and in- conspicuous. While the male flower is unopened, the stamens, which are fur- nished with an elastic tissue, curve in- wards; but as the ilower matures, they gradually become dry, and, a result of this dryness, spring outwards, spurt- ing the pollen into the air. In this way they assist the wind in disseminating the fecundating dust. The Wall-pellitory (Parietaria offici- nalis)J a common weed on old walls and in dry waste places, scatters its pollen in a similar manner. The coiled- up stamens are highly irritable, and at the proper time force asunder the seg- ments of the calyx which hold them down and liirt out their pollen. It is a remarkable fact that, in the her- maphrodite flowers of this plant, the brush-shaped stigma of the pistil falls off before the anthers dehisce, and thus, self-pollination is prevented. Closely related to the Nettles and Wall-pellitory is the equally remarkable Artillery-plant (Pile a microphylldj. This is a small plant, with leaves re- sembling those of Wild Thyme, and minute dioecious flowers, common enough in indoor ferneries. The Eng- lish name refers to the copious dis- charge of pollen when the stamens straighten themselves — a phenomenon which may be artificially induced by sprinkling the plant with water. The anthers empty themselves I'llOlO III/] FIG. 565. — WOOD SAGE (Teucrium scorodonia). The pale oclireous (lowers are much vi-nted by bees. The purplish stamens after shedding their pollen bend back to allow the pistil to occupy their former position. SOME PLANT MARRIAGES 461 instantaneously, the contents flying out like the puff of smoke from a distant gun. The only other group of wind-pollinated plants which need be noticed here is that which comprises the forms with immovable flowers. In these it is usual to find that provision is made for temporary storage of the pollen should no ivind be stirring ivhen the anthers dehisce. For instance, in the Arrow-grass (Triglochin pahistre] the pollen is rolled into the deep concavities of the perianth leaves ; while in the Sea-buckthorn (Hippophae rhamnoides) it is discharged into little bladders formed by the uniting concave scales in which the stamens lie. Let a warm dry wind spring up, and the bladders open by narrow chinks, and set free the pollen— which, however, can only escape a little at a time. The Broad-leaved Pond-weed (Potamogeton natans) is a good example of a wind-pollinated plant with immovable flowers. Here our chapter must close, though not for lack of matter to carry us farther. The subject of the Pollination of Plants is inexhaustible, and must ever remain so; for, in pursuit of the study, we are brought again and again— as in the study of the Life of Plants— to the borders of the Unknown Land. Here it is that questions press upon us which, as Sahleiden Photo by] FIQ. 566. — HORNBEAM (Carpinua betulus). The male flowers are in pendulous catkins two inches in length. The female flowers form a large spike, which lengthens after fertilization to three or four inches, and becomes pendulous. Those shown are the male catkins. 462 HUTCHINSON'S POPULAE BOTANY finely remarks, we can neither repel nor answer. " What has the wind to do with the date-harvest of Bileduljerid, and with the sustenance of millions of men ? What cares the gall-fly that on its activity depends the fig trade of Smyrna, and the food or support of thousands of human beings ? Or does the beetle, whose theft facilitates the increase of the Kamschatkan Lily, imagine that their bulbs shall be the means to save the whole popu- lation of Greenland from starvation in the following hard winter ? If FIG. 567. — SWEET CHESTNUT (Castama saliva}. The Ion!,' catkin marked (a) consists of male (lowers ; those marked (/>) are females. all this is the result of unsubstantial natural laws, whence this wonderful interdependence and connection of subordinate forces, to bring to pass events which have so deep an influence on the history of humanity ? We do, indeed, see into the mechanism of the puppet ; but who holds the strings, and directs all its motions to one purpose? Here closes the office of the naturalist, and, instead of answering, he turns from the world of space and lifeless matter upward to where, in holy anticipation, we seek the Ruler of Worlds." Photo by-] [Henri/ Irving. FIG. 568. — GRAPE VINE (Vitis vinifera). A familiar cultivated plant that climbs by means of tendrils, and has inconspicuous flowers." of peculiar [form. The fruits are be ies. Native of the Mediterranean region. 463 CHAPTER XIV THE PROMISE OF THE PLAXT THAT 18 TO BE . . . Fruit and seed, New loosed from thorn-bush, tree, and Haunting weed, And now by wing, or scale, or plume up-borne, Fare forth on pilgrimage. WHEX water, wind, or animal (or, it ma}* be. the unaided plant) has fulfilled its function as an agent of pollination, the true process of fertilization begins. The outcome of fertilization is the fruit. In popular language the term u fruit" may mean many things, but botanists usually confine it to the ripened pistil or ovary of a flower. Possibly this use of the term is rather too exclusive. Kerner would extend the definition to " everything which undergoes alteration after fertilization either in the flowers or flowering axis," and urges that as the changes in question are " for the purpose of promoting the interests of the embryo," whatever participates in this object is the fruit. However, not to appear singular, we will abide by the definitions of the text-books, and take it that a fruit is a ripened and developed ovary. How does this ripening and development take place ? The accom- panying figures will help us to understand the process. Fig. 570 represents an ideal section through a uniovular ovary just after pollin- ation, a is the stigma, upon which are six pollen-grains. The style (6) widens into the ovary (cc), which contains a single inverted ovule (d) — the latter not shown in section. We speak of the ovule as inverted because the rnicropyle (g) is not at the apex of the ovule, but, by a twisting round of the whole ovule, is brought close to the funide or point of attachment (/).* FIG. 569. — WHITE WATER-LILY (Castalia alba). * This is the commonest form of ovule, and is described as anatropoiis. It must be carefully distinguished from the bent A transverse section of the ovary, showins the ovules in the carpels. 464 THE PKOMISE OF THE PLANT THAT IS TO BE 465 FIG. 570. — UNIOVULAR OVARIES. The first t.liau'm the ovary in section before fertilization (the ovule not in section), (a) Stigma, upon which six pollen grains ; (b) style ; (c c) ovary containing a single inverted ovule (d) ; (/) stalk (funicle) of ovule ; (g) aperture (micropyle) of ovule throug above, (h) Antipodal hich the pollen-tube enters. In the second diagram the letters a to g are as ells ; (/•) central nucleus ; (m) egg-cell (oosphere) from which, after fertilization, the embryo plant is developed ; (nn) co-operating cells (synergidse) ; (/>) pollen-tube entering the micropyle; (r) inner envelope f ovule; (*) outer envelope of ovule. The space containing h, k, m, n is the embryo-sac; the part surrounding it (.r) is the nucellus. The second diagram shows the same pistil, but ,with the ovule also in section. Observe the structure of the ovule, here represented at the stage immediately preceding fertilization. Commencing from the outside, we have first a coat or envelope (s) — the outer integument ; secondly, an inner coat (r) — the inner integument ; and within that a mass of tissue (a;), repre- sented by the dark shading — the nucellus. Embedded in the nucellus is the embryo sac, which contains an abundance of protoplasm, with large vacuoles or campylotropous form, in which the ovule curves upon itself like a horseshoe, and so brings the micropyle near the base. This is well seen in the Pea (fig. 571) and in the seeds of Shepherd's Purse (Capsella bursa-pastoris). Straight or orthotropous ovules, which have the funicle and nucellus in the same straight line, are common among the (Tymnosperms, and occur also in the Dock family. The Yew (Taxus baccata) offers an excellent example of this form. n—12 466 HUTCHINSON'S POPULAR BOTANY FIG. 571. — CAMPYLOTROPUUS OVULE OF PEA. (m) Micro;>yle ; (/) funicle and a central nucleus (k) ; and in addi- tion to the protoplasm, a number of small cells (m, -», etc.). First and chief is the egg-cell or oosphere * (m). from which, after fertilization, the embryo plant is de- veloped. Its two sister-cells (n %), which co-operate in this work, are known as the synergidce. They are situated somewhat nearer the micropyle' (g) than the oosphere. and constitute with it the " egg appara- tus." The three cells at the opposite end of the embryo sac are the antipodal cells. Soon after their formation each of the antipodal cells becomes invested with a cell-wall, but they appear to play no part in any of the subsequent phenomena, and their use we are not at present able to estimate. Watch the process of fertilization. On putting forth its tube the pollen- grain shapes a course down the loose conducting tissue of the style until it reaches the micropyle of the ovule. The tube, it should be explained, is an outgrowth of the inner coat or inline of the pollen-grain through the extine or outer coat (fig. 559), and it bears at the end a reproductive nucleus, which is in fact the male sexual cell or male gamete. Forcing its way down the micropyle, the pollen-tube perforates the embryo sac, and then, opening at the tip, allows the reproductive element — which has meanwhile divided to form two male cells — to pass out. Thus released, the generative nuclei traverse the synergidse — which thereupon shrivel and collapse— and, with that, one of these male cells enters the egg-cell and fuses with the female nucleus. This is the act of fertilization. The cell formed by the fusion of the male and female nuclei is called the oosperm or embryonic cell ; and from this cell (as the latter name suggests) is eventually formed the embryo or baby plant — the essential part of the seed. Immediately after fertilization endo- sperm begins to form in the embryo sac, either by cell division — as in some Dicoty- ledons— or by free cell formation — as in all Monocotyledons and many Dicoty- ledons. The embryo sac meanwhile increases greatly in size and gradually FIG. 572.— SPINY FRUIT OF MEGAKRHIZA CAMFORNICA. * Called also the yennsphere and ovum. •ft Photo »y] FIG. 573. — DANDELION (Taraxacum officinale). The plumed fruits form a globe of down, which is broken by tho wind and the separat to a distance. 467 IE. Step. fruits sail lite parachutes 468 HUTCHINSON'S POPULAR BOTANY absorbs the tissue of the nucellus. In plants of the "Water-lily and Pepper orders (Nymphseacese and Piperacese) and a few others, a portion of the nucellus remains, and forms what is known as perisperm. When both the endosperm and perisperm are completely used up by the embryo in the course of its development, the ripe seed consists simply of a seed-coat (formed from the integuments of the ovule) and the embryo, and is described as ex- albuminous. In cases where the ripe seed contains endosperm as well as the embryo, it is called an albuminous seed. As we have already dealt with the subject in Chapter VI, we need not retrace the ground here. From what has been said, however, the distinction between a fruit and a seed must be at once evident. The former is a ripened and developed ovary ; the latter, an impregnated and matured ovule. The fruit, in fact, contains the seed or seeds, just as the ovary contains the ovule or ovules. In the Gymno- sperms, which have naked ovules, the seeds are of necessity naked also ; hence they are not true fruits. True fruits are, indeed, confined to the Monocotyledons and Dicotyledons. In dealing with the diversi- ties of form and external struc- ture of fruits and seeds, it is interesting to consider them in the light of Adaptation. By this means the inquiry is immensely simplified ; for it is evident that those diversities are mainly di- rected to one end — the dispersion of the seed. The seed, in fact, must be adapted to travel. Now seeds and fruits were great travellers centuries before Vasco da (lama and Columbus were heard of, and had crossed seas and continents, and planted colonies all over the world long before the earliest caravan set out from Bactria, or the first Phoenician merchantmen spread sail on the blue waters of the Mediterranean. The necessity for becoming travellers was imposed upon the vegetable community from the outset. Had those old- world fruits just fallen from their parents' arms, so to speak, and lain where they dropped, the consequences must have been disastrous. In a few years vegetation would have been almost choked ; the strongest plants would have killed out the weaker, whole families of plants would have thus become ex- tinct, and the distribution of the remainder would have been much retarded. FIG. 574. — WOOD-SORREL (Oxalis) EXPELLING ITS SEEDS. THE PROMISE OF - THE PLANT THAT IS TO BE 469 FIG. 575. — SEED OF WOOD- SORREL. The elastic outer integument Is burst- ing open to expel the seed. It is therefore a matter for thankfulness that provision has been made in nature for the dis- persal of the fruits and seeds of plants. This great end is effected in many ways. Sometimes the plant ejects its own offspring in a more or less forcible manner by means of special tissues which act as slings, catapults, etc. ; sometimes the fruits themselves are capable of creeping or hopping along the ground ; sometimes they are provided with plumes, aeroplanes, or with envelopes filled with air, which render them so buoyant that they are able to perform long aerial journeys, the least breeze being sufficient to carry them along : sometimes the wind lays hold of them when on the ground and drives them forward with rapidity : sometimes the water is their friend, and stream and torrent, lake and ocean, become instrumental in transporting them to new and distant homes ; sometimes the fruits are furnished with hooks or sticky secretions which facilitate their dispersion by birds and other animals. The Wood-sorrel (Oxalis acetosella), whose delicate white blossoms may be often seen peeping among the mossy uncovered roots of forest-trees, is one of our commonest wild-flowers. It offers a familiar example of plants with sling fruits. When the seeds are ready for dispersion, the capsules containing them burst open, and the strong tense tissue which covers each of the seeds being ruptured at the same time, the seed is jerked out to a con- siderable distance (figs. 574, 575). In the Squirting Cu- cumber (Ecballium elaterium. fig. 576) the arrangement is even more curious. The seeds are con- tained in a juicy pulp, which fills the fleshy and bristly "cucumber," and which is kept from bursting out by the hooked and stopper- , . , , 1 1 wv, — SQUIRTING CUCUMBER (Ecbalhum elatemum). When the fruit is ripe it breaks off from the stalk, and from this point the seeds. the Seeds are ripe, and pulp are squirted out with force. 470 HUTCHINSON'S POPULAR BOTANY the fruit severs itself from the stalk, and instantly the seeds are squirted out in a fountain of pulp through the unprotected hole. In the Touch- me-not Balsam (Impatiena noli-me-tangere, fig. 577) the five divisions of the capsule leap from the stalk when the seeds are ripe, and, twisting suddenly up, get rid of their offspring in a very summary manner. The Common Dandelion (Taraxacum officinale, fig. 573) offers the most familiar example of the dispersal of plumed fruits by means of the wind. Each of its white downy balls, "the schoolboy's clock in every town," is an aggregation of such fruits, waiting for the first breeze to scatter them. The beauty of these tiny parachutes, and the gracefulness of their motion as they float through the summer air, cannot be too greatly admired. The Tillandsias, many of which are epiphytes, have plumed fruits which are specially adapted for anchoring them to the bark of old trees, where they are able to ger- minate immediately. In Cirs^^lm nemo-rale, one of the Plume This- tles, the fruits just break away from their sessile plumes and fall to the ground, when- ever an obstacle is en- countered in the course of flight. Doubtless the obstacle gives suf- ficient promise of terra firrna below to encour- age them thus to slip their parachutes and risk a descent. Creeping fruits are characterized by their stiff bristles, which are peculiarly sensitive to mois- ture. As a result of this sensitiveness, the fruits continually change their position, and are able to propel themselves along in a definite direction, a hygroscopic arrangement which enables them to be carried long distances. Even jumping fruits are not unknown. Insect activity within the fruit is the cause of the phenomenon, and one of its effects is undoubtedly the dispersion of the seeds. Two plants are known which have so-called "jumping beans'" — viz., Sebastiania palmeri and S. bilocularis; and the insects which cause the motion are Carpocapsa saltitans in the former, and Grapholitha sebastiania in the latter. Sebastiania palmeri is a very peculiar tree. It was discovered not many years since in a morass, half FIG. 577. — TOUCH-ME-NOT BALSAM (Impatiena noli-me-tctngere) EXPELLING ITS SEEDS. 471 472 HUTCHINSON'S POPULAR BOTANY a mile square, in the neighbourhood of Alamos, Mexico. The fruit is of triangular shape, divided into three equal portions by strongly defined lines. Two of these parts contain a small spherical black seed; the third, a "jumper" or small maggot. On falling to the ground the fruit splits, and that portion which contains the maggot immediately starts off, hopping in an extraordinary manner away from the tree on which it grew. The object of these movements has not yet been discovered, but the theory is that the maggot instinctively knows that if it remains near the parent tree it will be destroyed by an enemy. The insect lives upon the contained seed, and has no desire to escape— indeed, seems to be extremely comfortable in its dark quarters. If a small hole is carefully bored in the shell, the maggot instantly sets to work to repair the damage, and in a very short time will have closed the hole with a fine silky web. After this is done the insect resumes its tireless and saltatory travels. As k •r ti / FIG. 579. — STRAWBERRY (Fragaria vesca). The first figure shows (a) ovary, (6) style, and (c) lobed stigma. The second figure is a section through the receptacle (a) of an unripe " berry," with membranous pistils seated on the surface. The third figure shows the same in a ripe condition with carpels on the exterior; and the remaining figure is a section through one of the carpels, showing the contained seed. there is no hole or other indication of a way by which the shell could be entered, it is supposed that the egg is laid in the flower before the fruit is formed ; probably also, the moth which lays the egg cross-pollinates the flower at the same time. The perfect insect is a grey-brown moth, with speckled upper wings which measure three-quarters of an inch from tip to tip. The moth releases itself from its prison by chiselling out a piece of the hard shell, like a circular pavement-trap in miniature. The most delicate fret-saw, even in skilled hands, could not do the work better. It must be understood that these "jumping beans" never produce seedlings,, for the contained larva destroys the seed. Instances are even known of whole plants which migrate from place to place when their fruits are ripe. Of this sort are the wonderful " wind- witches " of the Russian steppes, which have so appealed to the imagination of the peasants of those regions. At the fruiting stage the stiff erect. THE PROMISE OF THE PLANT THAT IS TO BE 473 flowering stems of this plant, which spring from a common axis almost level with the root, curve outwards to the circumference of the plants, and by that means give a strong pull to the radish-shaped root, sufficient to force it from the ground. The environment of the plant favours this singular and apparently suicidal proceed- ing, for the earth during the summer season is full of cracks. Then, when the wind comes howling over the steppes, the plant is caught up and driven along with others of its kind, and together they fly bounding over the plain. One by one their wild careers are checked, and each settles down to resting-place. Having offered these general remarks, we will of the Phanerogamic Fruit in more detail. A fruit or ripened ovary consists, normally speaking, of two parts — the pro- tective enveloping case, known as the pericarp, and the seed or seeds (ripened ovules). The pericarp consists of three layers, each of which has a distinguishing name. The outermost layer — i.e. the in- tegument or skin of the fruit — is the epi- carp ; the middle layer is the mesocarp : and the inner coat the endocarp. When, as middle layer is of a fleshy or succulent nature, It was noticed a few pages back that parts of plants are sometimes described as fruits which are not true fruits at all. "We call these spurious fruits pseudocarps. The strawberry, apple, fig, and mulberry are familiar examples. The red, succulent, fleshy part of the Strawberry is not a ripened ovary, but the greatly swollen re- ceptacle or thalamus of the flower ; and the real fruits are the small, dry, seed-like carpels scattered over its surface. In an Apple the edible part is not the ovary alone, but embraces the succulent and en- larged floral receptacle, which also, as in the Strawberry, forms the bulk of the FIG. 580. — APPLE. Longitudinal section of jionie. p • 1-1 1 he remaining dry dehiscent fruits which FlG- 587.— MEADOW-SAFFRON. Transverse section, illustrating septicida 478 HUTCHINSON'S POPULAR BOTANY FIG. 588. — DIAGRAMMATIC REPRESENTATION OF FIGS. 586, 587, AND 585. are sometimes described as capsules are the follicle, the legume, the siliqua, and the silicula. We will take them in that order. The follicle is a superior, one-celled fruit, containing one or more seeds. which are liberated in most instances by a ventral suture only. Magnolia glauca and some other species of Magnolia are exceptions. As a rule, several follicles are collected in a cluster at the end of a flower-stalk, but solitary follicles are common in Proteacese; and there are a few plants (e.g. the Pseony, normally developing two or more follicles with each flower, which occasionally produce but one. The Columbine (Aquilegia) and Lark- spur (Delphinium} offer good examples of the follicle. The legume or pod resembles the follicle in that it arises from a single carpel ; but, unlike the follicle, it dehisces at both sutures. This is the characteristic fruit of the great order Leguminosece, to which the Pea and Bean belong. The legumes assume a curious twisted form in the small genus Scorpiurus, which includes the interesting Caterpillar-plant (8. vermiculata, fig. 594), and a spiral form in the Purple Lucerne (Medicago sativa, fig. 597). When the pod is contracted in a bead-like (moniliform manner, as in the Gum Arabic plant (Acacia arabica, fig. 601), it is termed a lomentum. The legumes of the Earth-nut (Arachis hypogcea, fig. 599) deserve notice on account of peculiarities other than those of form. The specific name hypogcea (Greek upo ge, under ground) is an allusion to the curious circum- stance that the young pods, as they begin to mature, are forced into the earth by a lengthen- ing of the flower-stalks, and ripen their seeds below the ground. This phenomenon is not confined to the Earth-nut, but has been ob- served in a few other plants — Trifolium subter- raneum. for example, and the Sweet Violet ' rrF ' , (Vwlo, odorata). 1 he fruits of the latter are llot leguminous. Plants with burying fruits, FIG. 589. — PIMPERNEL. The fruit is a pyxidium, which spats trans- verseiy p*1* *«°* Photo Ity] IE. Xfep. FIG. 590. — HORSE-CHESTNUT (&s:ulus hippocastanum). The prickly fruit is a succulent capsule, and when ripe it splits into two or three valves to set free the large seeds known as Conkers. Mountain regions of GREECE, PERSIA, and NORTHERN I.VDIA. 479 480 HUTCHINSON'S POPULAR BOTANY says Kerner, " have always been a source of wonder to botanists, and their number is not large. The best known examples are Arachis hypogcea, Cardamine chenopodiifolia, Linaria cymbcdaria, Phrynium micans, Trifolium fiubtei*raneum, and Vie-in amphicarpa. If these plants were only to bring fruit to maturity underground, or were to draw all their fruits below the ground as soon as the seeds were mature, in order that germination and the development of new plants might ensue at that spot, their behaviour would imply a renunciation of dispersion to any distance, and the phe- nomenon would be highly enigmatic. The puzzle is satisfactorily solved, however, when we take into account the fact that all these plants in- variably have the chance of being dispersed to great distances either before the fruits become concealed in the earth, or by means of a second form of fruit which ripens aboveground, and is evidently adapted to being scattered abroad through the agency of animals, or by means of aerial or Photo ft;/] [E. Step. FIG. 591. — BRAZIL NUT (Bertholletia excelsa). The hard-shelled triangular nuts to the number of fifteen or twenty are enclosed in a thick-walled, woody fruit which oan only be broken by , • i • , i , -i f , i legume. " for the express purpose of sticking to the tails of the FIG. 596. — STOCK (Matthiola annua). A siliqua, and the same dehiscing. Photo ly] [£. Step. FIG. 598. — IVY-LEAVED TOADFLAX (Linaria cymbalaria). A Continental plant that has become well-established on our old walls. The fruit-stalk bends down and moves about until it finds a chink into which the capsule is thrust, and there on ripening it discharges its seeds. 483 484 HUTCHINSON'S POPULAR BOTANY wild horses that roam the plains of South America"; and certainly one of the objects of the hooked spines and bristles of fruits of whatever kind is their dispersion by animals. Kerner estimates that the fruits and seeds of about 10 per cent, of all Flowering Plants are provided with pro- cesses of this description, some of which take the form of hooks and others of barbs. In this case the Marty nia fruit splits to release the con- tained seeds which are gradu- ally shaken out by the effort of the animal to get rid of its encumbrance. The Goose- grass (Galium aparine), a long, weak, straggling plant very common in our hedges and thickets, has small fruits (dry, indehiscent pericarps, in this case) which are liter- ally covered with hooked bris- tles. Country people call the plant " cleavers," from its habit of cleaving to objects with which it is brought in contact, and children like to throw the hispid fruits at one another for the fun of seeing them " stick." In the Bur- weed (Xanthium, fig. 604) the hooks are borne upon the hardened involucre, which grows about and covers the one-seeded fruit. Very simi- lar in effect are the top- shaped fruits of Agrimony (Ayrimonia, eupatoria), which become detached from the plant by every fur-clad crea- ture that touches it in pass- ing. A walk through the pastures in early autumn will result in our nether garments being thickly coated with these fruits. FIG. 599. — EABTH-NUT (Arachia hypogcea). The young pods are thrust into the earth by the lengthening of their stalks, and there they ripen their seeds. THE PEOMISE OF THE PLANT THAT IS TO BE 485 FIG. 600. — ROSE OF JERICHO (Anastatica). Fruiting branch. The capsules of the African Grapnel- plant (Harpagophytum procumbens} are pro- vided with claw-like spines of a particularly powerful kind, which grasp the hoofs of unwary animals in the Orange River region where the plant abounds, causing them the greatest pain ; nor is there relief from the torment till the capsule splits up to release the seeds. Thus far our atten- tion has been mainly confined to dehiscent fruits ; we will now speak a little of those which never open spontane- ously, or, in other words, are indehiscent. It will be seen as we proceed that the provisions for dispersion, in the way of hairs, curved bristles, and hooked spines on the one hand, and of wings, plumes, etc., on the other, are far more common in indehiscent than in dehiscent fruits ; and the reason is obvious. The pericarp, which releases its seeds spontaneously at the time of ripening, has done its work when de- hiscence has taken place, and the seeds are left, so to speak, to their own resources. The broken, empty seed-case has no further use. But in the case of an indehiscent fruit, where pericarp and seed do not part com- pany on the ripening of the latter, a con- trivance of some kind to assist dispersion is clearly a valuable provision. Take a stone-fruit, such as the plum, by way of illustration (fig. 608). A plum is a fleshy, indehiscent fruit called a drupe, with a stony endocarp, which invests the " ker- nel" or seed (fig.^607). (This may be ac- FlG 602_ HONESTY (Lunaria annua). cepted as a definition of a drupe.) Now, suiquas of elliptical shape. FIG. 601. — GUM ARABIC-TREE ( Acacia arabica). A lomentum. 486 HUTCHINSON'S POPULAR BOTANY FIG. 603. — EVERGREEN CANDYTUFT (Iberis aempervirens). A silieula. as the seed of the plum matures, the fleshy meso- carp, or sarcocarp, becomes more succulent and loses its acidity, while the green epicarp, hitherto only to be distinguished with difficulty from the surround- ing leaves, assumes a yellow, red, or purple colour, and so becomes very conspicuous. By reason of these changes, animals — particularly birds — are attracted to the fruits, which they devour greedily. The seeds, thanks to their environment of stony endocarp, resist digestion, and in many cases are transported to great distances. The cherry, apricot, peach, and a host of other drupaceous fruits undergo very similar trans- formations and are distributed by similar means. The fruit of the Coco-nut Palm (Cocos nucifera), with its fibrous mesocarp, is also a drupe, though some botanists speak of it as a nut. This is one of the fruits disseminated by water — a fact which ac- counts for the prevalence of palm-groves on the coral islands of the Pacific. In the vicinity of Key West, an island of the Florida reefs, and as far north as Jupiter Inlet, two hundred miles from Key "West, the sandy beach is lined with Coco-nut Palms, which owe their presence there to the wrecking of a vessel which had a cargo of the nuts on board. The Double or Sea Coco-nut (Lodoicea seychellarum, fig. 606) is distributed by similar means. " The Seychelles," says Miss Gordon Gumming in her Two Happy Years in Ceylon, " contribute a fine specimen of their own particular Palm, the Coco-de-mer [Sea Coco-nut], which was so long known only by the great double nuts (shaped like a kidney when cut open) which tidal currents floated far out on the Indian Ocean and to the shores of the Maldive Islands, where they were occasionally picked up by sailors and brought home to puzzle botanists. It was not till last • [i.e., the eighteenth] century that the parent Palm was discovered in the Seychelles, and it was found that the Palm, with a fruit like twin coco-nuts, bears a crown of huge fan-shaped leaves, akin to those of the Palmyra Palm, crowning a stem a hundred feet high." Another common form of indehiscent fruit is the berry. In a berry the whole of the seed-case or pericarp becomes fleshy or succulent — there is FIG. 604.— BURWEED (Xan- no stony endocarp as in the drupe. The grape, thium strumarium). currant, gooseberry, and mistletoe are well-known with hook-ciad involucre. examples. The gourd is really a huge berry 487 488 HUTCHINSON'S POPULAR BOTANY FIG. 606. — DOUBLE COCO-NUT (Lodoicea seychellarum). A drupe. with a hard outer layer, but it is more often called a pepo (fig. 611). Dispersion of the seeds of berries is effected largely by animals, under circumstances very similar to those attending the seed dis- persal of drupaceous fruits. The seed- coats resist the action of digestive juices as effectually as does the stony endocarp of the plum or cherry. Few indehiscent fruits are more puz- zling on a first examination than the orange. The development of the three layers of the pericarp is very remarkable, and forms one of the characteristics of a remarkable kind of fruit — the hespemdium (fig. 612). The peel of the orange consists of epicarp and mesocarp ; while the membranous partitions which project internally towards the centre of the fruit, and divide off the juicy pulp into separate groups of cells (the misnamed " quarters " of the orange) consist of endocarp. The pulp itself, in which the " pips " or seeds are embedded, is a development of succulent cells (internal hairs) from the inner lining of the ovary — i.e., from the endocarp. The lemon, shaddock, etc., have the same distinguishing feature, and are equally good examples of the hesperidium. The three sorts of indehiscent fruits which we have been considering — drupe, berry, and hesperidium — are all succulent ; the others are dry. They are the achene, nut, caryopsis, and cypsela. A dry indehiscent fruit developed from a pistil with single carpel is an achene ; if the pericarp is thin and leathery, and not adherent to the seed-coat, it is an achene-; if hard and woody, a nut. Any dry one- seeded indehiscent fruit with a hard endo- carp is called a nut. As a rule, a nut has but one chamber, the partition-walls dis- appearing by atrophy as the fruit develops. The fruits of the Buttercups (fig. 613) are achenes ; the fruits of the Hazel (Corylus, fig. 614) are nuts. The husk which partly envelops the hazel-nut is formed by greatly enlarged bracts. FIG. 607. — SEC- TION THROUGH THE " STONE " OF A PLUM. FIG. 608. — SECTION THROUGH A PLUM. Showing the "stone" invested by the fleshy mesocarp. THE PROMISE OF THE PLANT THAT IS TO BE 489 FIG. 609. — CONE or CHINESE ARBOR- VIT^E (Thuja orientalis). In the Oak (Quercus, fig. 624) the nuts, usually called acorns, are seated in cups or cupules of bracts, which, curiously enough, are only formed after fertilization. In the British Oak (Quercus robur] these cups are rough on the exterior ; but in those of the Turkey Oak (Quercus cerris) they are coated with moss-like outgrowths. The order Cupu- liferce derives its name from these vegetable cups. Beech-nuts, the fruits of Fagus syl- vatica: are contained in a spiky husk — the enlarged four-partite involucre of bracts — which, on a superficial view, might be mis- taken for the pericarp. Each involucre usually contains one or two nuts, which are sharp-cornered and triangular, and which, on the splitting of the husk in the autumn, fall to the ground. Fruit dispersion in cupuliferous plants is largely assisted by animals. " Many noble oaks," says a writer in the Zoologist, quoted by Dr. Cooke, " have been planted by the squirrel, who unconsciously yields no inconsiderable boon to the domain he in- fests. Towards autumn this provident little animal mounts the branches of Oak-trees, strips off the acorns and buries them in the earth, as a supply of food against the severities of winter. He is most probably not gifted with a memory of sufficient re- tention to enable him to find every one he secretes, which are thus left in the ground, and springing up the following year, finally grow into magnificent trees. Pheasants devour num- bers of acorns in the autumn, some of which, having passed through the stomach, probably germinate." A dry fruit whose leathery pericarp closely adheres to the seed-coat is termed a caryopsis. This is the characteristic fruit of the family of Grasses. The Wheat- plant (Triticum) presents a good type of the caryopsis. A full-grown and perfect grain of wheat will, on examination, be Flo_ 6n._GouBD (Cucurbita pepo). found tO resemble the accompanying figure A berry with hard exterior; also called a pepo. FIG. 610. — MILK- THISTLE (Silybum marianum). Cypsela with sessile pappus. 490 HUTCHINSON'S POPULAR BOTANY FIG. 612. — MYRTLE-LEAVED ORANGE (Citruf aurantium, var. ). A hesperidium. (fig. 615). In form it is a compressed oval, and is en- closed, firstly, in certain chaffy scales, which are easily separ- ated from it ; then the mem- branous pericarp or ovary ; and within that, the testa, which is the outer integument of the seed, and to which the pericarp closely adheres. Thus a grain of wheat is not merely a seed. It consists of a pericarp as well as seed, and consequently is a true fruit. Fig. 617 shows one of the caryopses of a curious Indian Grass (Coix lachryma), popularly known as Job's Tears. The peculiar heavy grey pearly fruits, hanging in clusters out of their sheaths, give this plant a unique appearance. It is to be noticed that the caryopsis only differs from the achene in one particular. In the former, the pericarp is closely adherent to the testa of the seed ; in the latter there is no adhesion whatever. Both are superior fruits (the ovaries being free from and rising above the perianth) ; and in this respect, and this only, they differ from the cypsela, which is inferior. The cypsela is the characteristic fruit of the great order of Composites ; and its usual addition of a stipitate or sessile pappus admirably adapts it for dispersion by the wind (figs. 610, 616). Johnston's Botany of the Eastern Borders contains some apposite re- marks on the wind dispersion of plumed cypselas, and use- fully supplements what has been already said on this sub- ject in our preliminary re- marks. " Elevated on the apex of a long beak," says this writer, " the parachute of the seed of the G-oatsbeard (Tra- gopogon pratensis) consists of a number of slender spokes, which diffuse themselves circularly, and are ' telarly FIG. 613. — URCHIN CROWFOOT (Ranunculus arvensis). An achene. The second figure shows the fruit and seed in sectii 492 HUTCHINSON'S POPULAB BOTANY FIG. 615.— WHEAT (Triticum). A section through the grain or caryopsis. interwoven,' somewhat after the fashion of the spider's web. This comparatively intricate structure is given as a countervail to the great size and weight of the seed. The down of Dandelion is supported on a long and slender pedicel, and is an object of vulgar ad- miration ; but it scarcely equals in beauty the simi- larly patterned fruit of the Hdmvnthia. The Thistle's down is, on the contrary, sessile — the threads being sometimes only spinous, at other times plumed like a feather — and the down of the latter is peculiarly light. The coronet of the Carline-thistle (Carlina) is remark- able for its elegance and circular spread and plumage, and buoys easily its silky coated seed [i.e., fruit]. In the Sow-thistles (Sonctnis] what we most admire is the ribbed and striated seeds [fruits], but the down that diffuses them is abundant and of pure whiteness. The seeds [fruits] of the Coltsfoot (Tussilago) afford an example of a structure, common in the order, where the seed [fruit] is surmounted by a tuft of silken hairs, armed at regular intervals with a series of denticles or spines, only visible with a good magnifier. We have a contrast to this in the curious fruit of the Blue-bottle (Centaurea cyanus), which has a small tuft of asbestine spines at the base, and a large but short tuft of rigid stout lanceolate spines on the top, the edges of each of them indented with close and sharp serratures like a saw. This tuft cannot float the seed in the air, but it will obviously direct and hasten its descent into the soil, and it will be re- marked that the forward direction of the spines must be opposed to every influence to cast them up again, after having been buried under the surface." "We have now dealt with two of the three great classes into which all true Phanerogamic fruits may be divided ; it remains only to speak of the third class — viz., the splitting fruits, or schizocarps. Schizocarps are multiple, usually indehiscent, FIG 617— JOB'S TEARS fruits? which split into one-seeded portions called \Goix lachryma). mericarps, resembling nuts or achenes. Each of A caryopsis. these portions is itself a true fruit. The splitting FIG. 616. — DANDELION (Taraxacum). A cypsela with stipitate pappus. THE PROMISE OF THE PLANT THAT [IS TO BE 493 FIG. 618. — SAMPHIRE (Crithmum mariti- mum). A cremocarp. may be either longitudinal or transverse ; and. of course, the number of parts into which a given schizo- carp will divide is determined by the number of its seeds. One with two seeds will split into two parts ; another with five seeds, into five parts ; and so forth : and this fact has led to the classification of schizocarps into bipartite, tripartite, quadripartite, quinquepartite, and multipartite. The well-known fruit of the Maples (Acer, fig. 628) is a bipartite schizocarp. Its two brown- winged meri- carps are known as samaras— a, name applied to all winged mericarps. These wings carry the two heavy seeds to a considerable distance from the parent tree. It has been ascertained by experiment that, when deprived of the wings, the seeds drop to the ground in one-fourth of the time taken by the winged fruit to ac- complish the same distance. In the double fruits of many Umbelliferous plants, the mericarps separate at their lower parts, but remain attached at their apex to a fork-like filiform process, the carpophore, as is well shown in the Samphire (Crith- mum maritimum, fig. 618). Bipartite schizocarps which follow this type are known as cremocarps or hanging fruits. In some Umbelliferse the cremocarps are winged. Winged fruits and seeds (for we may speak of them together) are adapted for dis- persion by the wind. They reach their highest de- velopment in the Trumpet-flowers (Bignoniacece), where the large wings extend three or four inches, " and the seeds float like a large butterfly, wafted from place to place, until a secure home is reached." In many — perhaps most — cases, the wings are not able to sustain the fruits in the air unless a pretty strong wind is blowing ; but it must not be forgotten that the wind is the great agent for detaching the fruits from the parent tree, arid the same gust which loosens a cluster of samaras from the bough may A quadripartite FIG. 619. — WYCH ELM (Ulmus montana). A samara. The fruit proper (in the centre) is shown in section. 494 HUTCHINSON'S POPULAR BOTANY FIG. 621. — COMMON MALLOW (Malva sylvestris). A multipartite schizocarp. sweep them many yards through the air before its force is spent. The other kinds of splitting fruits named above require but little de- scription, and the accompanying illustrations will help to fix their distinctive features in the memory. Fig. 622 shows a tripartite, and fig. 620 a quadripartite schizocarp — the former of the Garden Nastur- tium (Tropceolum majus), the latter of the Black Horehound (Ballota mi-grab). Two quinquepartite schizocarps are depicted in fig. 623 — one of them in the act of splitting. They are fruits of the Bloody Cranesbill (Geranium sanguineum). Fig. 621 is a multipartite schizocarp of the Common Mallow (Malva sylves- tris}. Like the Touch-me-not Balsam (Impatiens noli-me-tangere\ of which we have already given some account (p. 476), the fruits of the Bloody Cranesbill are sling-fruits. " If you would wish to catch the Ger- a n u m i 11 the act of sow- FIG. 622. — NASTURTIUM (Tropceolum majus). A. tripartite schizocarp. FIG. 623.- (Geranium A quinquepartite schizocarp, or sling-fruit. 1 11 g its seeds," says Dr. Lindley, " gather a little branch of the ripe fruit on a fine summer's morning before the dew is off it, and put it in the sun. By degrees the fruits will dry, and if you watch them, you will be surprised by some of them, on a sudden, emitting a snapping sound, and you may see first one and then another of the carpels quickly curving upwards towards the top of the style, opening at the same time by their face, so as to let this seed drop out." All this commo- tion is caused by the elongation of 495 496 HUTCHINSON'S POPULAR BOTANY FIG. 625. — POPLAR (Populus). Part of fruiting catkin discharging its seeds, which support a tuft of fine silky hairs which assist dispersion. the axis of the style after its five-partite outer layer (to the base of which the car- pels are attached) has ceased to grow. A state of great tension is thus produced, and when the splitting takes place the carpels are actually pulled out by the roots, whereupon they roll up upon them- selves as though frightened at what they have done. In -the Marsh-cranesbill (G. palustre) the contraction is so violent that the seeds are hurled to a considerable distance. A minute description of the external forms and subsidiary appendages of the seeds of plants hardly falls within the scope of the present work. The testa, or outer integument, may be smooth, as in the Bitter Cucumber (Ci- trullus colocynthis] ; reticulated, as in Larkspur (Delphinium, fig. 593) ; papillose, as in thf Corn-cockle {Lychnis githago, fig. 626) ; ridged, as in the Rangoon Creeper (Quisqualis indica, fig. 629); or woolly, as in the Brazilian climbing shrub, Trigonia villosa (fig. 633). The seed of Leptodermis lanceolata (fig. 632), a Bengal- ese evergreen shrub, is enclosed in a re- ticulated sac of endocarp ; while others are more or less enveloped in a remark- able appendage known as the arillus, which springs from their point of attach- ment to the placenta. The arillus is split into long silky hairs in the Willow (Salix) ; in the Nutmeg-tree (Myris- tica moschata] it consists of a dry flocculent coat (from which the mace of commerce is obtained) ; and in the Common Yew (Taxus baccata] it is succulent. The manner in which the aril of the Yew grows up around the seed is shown in fig. 631. Winged seeds are common in the G-ynino- sperms, and are borne on scales, which are hence called ovuliferous scales. The Scots Pine (Pinus sylvestris) furnishes a ready example. On a dry breezy day the cones open with a crackling sound and set free the seeds, which fly twirling FIG. 626. — CORN- COCKLE (Lychnis githago). Tapillose seed. FIG. 627.— L ARKSPUR (Delphinium). A reticulated seed. FIG. 628. — SYCAMORE (Acer pseudo- platenus). Samaras or bipartite schizocarp. THE PROMISE OF THE PLANT THAT IS TO BE 497 FIG. 630. — HOP HOKNBEAM (Ostrya carpinifolia). Female catkin, and one involucre opened to show the seed. through the air. It is impossible to open a pine-cone before its time without hacking it to pieces, and yet the mechanism by which the opening is effected naturally is very simple. The cen- tral column or stalk to which the scales are attached begins to grow, and this has the effect of separating all the scales. The wing ^tyll'l&yua CIS indica). of the seed is an upper layer of the scale, from which it Ridged seed. becomes detached when the seed is ripe. In a breeze sufficiently strong to pick them from between the scales of the cone, the seeds go spinning through the air to a distance of eighty or a hundred yards. In the Hop Hornbeam (Ostrya carpinifolia) the seeds are contained in inflated involucres, which hang in catkin-like clusters from the branch, and are readily borne about by the wind (fig. 630). In the Hornbeam (Carpinus betulus) the involucre is very large and three-lobed. In the Birch (Betula alba) the seeds, to a great number, are borne in cylindrical cones, the scales of which loosen in dry weather to set them free. They are quite small, but each is provided with a pair of thin wings, upon which they flutter away from 'the tree like a swarm of tiny flies — which indeed they closely resemble. So abundant is this seed-fall that where birch trees are plentiful the ground around them appears to be covered with a thick coating of bran. The seeds of the Willow-herb (Epilobiuiri) and some other plants are FIG. 631. — YEW (Taxus baccata). Fruiting shoot showing development of the arillus. (a) Female flower surrounded by scale-like bracts. (6) A later ?tage : the arillus (r) growing up around the seed, (c) A ripe seed surrounded by the fleshy red arillus. n—14 498 HUTCHINSON'S POPULAR BOTANY FIG. 633. — Trigonia villosa. Seed covered with long woolly hairs. furnished with hairy coronets which assist dispersion ; while those of the Poplar and Willow (Populus, fig. 625, and Salix) are provided with a silky fluff, which subserves the same purpose, Myriads of such seeds get stuck in the soft muddy banks of rivers, where they are sucked into the soil and quickly germinate. Much the same happens in the case of the Cotton-grasses (Erio- phorum), where the long silky hairs that represented the perianth at flowering time (see fig. 557) remain at- tached to the fruit and entirely surround it. When they have been carried off by the wind and sink among the sphagnum and other marsh-plants, the delicate filaments get clogged with moisture which at once fixes the seed in a suitable situation for the future plant and sets up the right conditions for germination. Some seeds appearto be designed speci- ally to impose upon animals and induce them to help in the work of dispersion. Among our smaller herbs some, like Cow-wheat (Mdampyrum), produce seeds that closely resemble the cocoons of ants — the so-called "ants'-eggs" — and these have been seen to be picked up by ants and carried away to their nests, where, of course, they germin- ate. But even birds are similarly imposed upon. In the case of a grain-eating bird a seed eaten and passed through the grind- ing apparatus known as the gizzard would have little chance of ever escaping and germinating ; but with insectivorous birds the conditions are different. A seed that resembled a beetle or a small caterpillar would form an attraction to such a bird, and when swallowed would have every chance of passing un- injured through the digestive tract and being voided at some distance from the shrub upon which it was eaten. Biserrula pelecinus produces a seed-pod that closely resembles a centipede ; Martynia diandra has a seed which looks like a beetle with long antennae ; the seeds of the Castor-oil plants (Ricinus) are like swollen ticks, and those of Jatropha are exactly like the upper side of a beetle. FIG. 632. — Lepto- dermis lanceolala An evergreen of Ben- gal. A seed enclosed in reticulated sac of endocarp. FIG. 634. — YEW. Section through ripe seed and arillus. IE. Step. Fia. 635. — AUSTRIAN PINE (Pinus laricio, var. austriaca). In general similar to the Scots Pine, but with much longer leaves and larger (Jones, which are almost horizontal on the Shoot. CENTRAL AND SOUTHERN EUROPE, and WESTERN ASIA. CHAPTER XIV HIDDEN MARRIAGES " Twas a most secret marriage." "I pray you tell me of it." Old Play. WE have already glanced briefly at the phenomenon of reproduction by spores, and cited examples from the principal groups of the Crypto- gamia — the so-called Flowerless Plants — but these plants are so numerous, and they are divided into so many classes and orders, each with its own particular variation of the reproductive process, that a rather fuller treat- ment of this phase of their economy seems called for. Though none of them produces the petals and sepals which to the public eye constitute the sole claim to the title of flower, and though in some there is not the Photo by] FIG. 636. — MAIDENHAIR SPLEENWORT (Asplenium trichomams). One of the prettiest of our ferns. Common on rocks and old walls in some districts. 500 HIDDEN MARRIAGES 501 faintest approach to a sexual union, the term " flowerless " as applied to the entire division of these plants is somewhat inappropriate and misleading. In many of the groups the essential organs of Phanerogams are represented by antherids and archegones, and the female element has to be fertilized by the male before a true embryo can be formed. Until recent years the term spore was made to do duty in this division as the name for bodies of widely differing values, and the result has been that much confusion is caused in the minds of students. To-day botanists proceed upon the more sensible plan of giving distinctive names to the body resulting from special methods of fertilization, in harmony with those used for Phanerogams, restricting the use of spore to those propagative bodies that are produced without fertilization. We shall adopt this terminology in the main here. The vast majority of the Cryp- togamic Plants are composed en- tirely of cellular tissue. Scalari- form tracheides are the most frequent form of thickening in the xylem, and sieve-tubes occur commonly in the phloem, but true vessels formed by the union of cells are rare. Respecting the diversity in the foliar organs of the Vascular Cryptogams, Messrs. Bennett and Murray have given in a paragraph a clear view of the principal types : " The size and form of the leaves are extremely various. In Lycopodium, Selaginella, and some other genera, they are very small, unsegmented, and lanceolate, not unlike those of mosses, and form a dense imbricated clothing to the stem ; in Psilotum they are altogether rudimentary; in the Equisetacese they are reduced to FIG. 637. — HARD F£RN (Lomaria spicant). (a) Barren fronds, (b) Fertile frond. 502 HUTCHINSON'S POPULAR BOTANY FIG. 638. — MALE FERN. A pinnule, or lobe of a pinna. The roundish scales are indusia covering the sori. divisions or teeth of a membranous sheath ; in Isoetes (Selaginellacese), Pilularia (Rhizocarpese), and Phylloglossum (Lycopodiacese) they are long, narrow, and awl-shaped. In some ferns the barren and fertile leaves differ from one another in appearance and especially in the degree of division of the lamina. In Salvinia they are of two kinds, one floating on the surface of the water and entire ; the other submerged, very finely divided, and performing the functions of a root ; in Azolla (Rhizocarpess) they are floating and bilobed. In some genera of Filices and their allies the leaves are quite entire ; in the Hymeno- phyllesB they are very delicate, consisting of only a single layer of cells, and in the smaller species closely resemble those of the f oliose Hepaticse ; while in most ferns they are of considerable (in the tree-ferns of gigantic) size, with well-marked petiole, rachis, and lamina, and distinguished by the great extent to which the lamina is divided. In most cases (except the Hymenophyllacese) they are abundantly provided with stomates. The tissue beneath the epiderm consists of a parenchymatous mesophyll containing abundance of chlorophyll, the portion of which adjacent to the upper epiderm is frequently developed as palisade-parenchyme. This mesophyll is permeated by ' vascular ' bundles or veins, which branch off from the cauline bundles, and are distinguished in the majority of ferns by their dichotomous mode of branching, in contrast to the reticulate anastomosing in Dicotyledons, and the parallel arrangement in most Monocotyledons. Among Gymnosperms a similar arrangement is presented by Salisburia and Stangeria. The floral metamorphosis of the leaves of Flowering Plants does not occur in Vascular Cryptogams, nor their special agglomeration round the organs of repro- duction as in Mosses." The spore-case (sporange) varies greatly in the different families, and is variously grouped, but there is more uniformity in the origin of the spore itself, which is produced much in the same way as the pollen-grain of Flowering Plants. A sin- FIG 639. MALE FERN. §^e ce^? or group of cells, shows by the nature of (a) A sorus covered by its mdusium. its contents at an early period that it differs from w A gporange spuwgg to s ^ surroun(jing cellular tissue. It is known as Photo by] \.E- StfP- Fio. 640. — MALE FERN (Nephrodium filix-mas). So called from its robust habit of growth. One of the most familiar of our woodland and hedgerow ferns. 503 504 HUTCHINSON'S POPULAR BOTANY FIG. 641. — A PKOTHALLITJM. the archespore, and from it is de- veloped the sporogenous tissue, which divides and subdivides into the mother- cells from which the spores originate. The Vascular Cryptogams (Pterido- phyta) are divided into the following Classes and Orders : — PTERrDOPHYTA. CLASS ORDER I. Filicinae 1. Filices, or Ferns. 2. Hydropterideae, or Water-ferns. II. Equisetinae 3. Equisetaceae, or Horse- tails III. Lycopodinae 4. Lycopodiaceae, or Club Mosses. 5. Selaginellaceae, or Sela- ginellas and Quill- worts. The scale-like body that results from the germination of a fern-spore, (a) Archegonia. (r) Rootlets. The Order Filices or Ferns is the best-known of all the Cryptogams and most of its families have been well worked out. They are chiefly perennial herbs (very few annual), though some have shrubby stems or root-stocks, and the tree-ferns are arborescent. Their leaves, or fronds, may be simple, as in the case of the Common Hartstongue (Scolo- pendrium vulgare, finely subdivided like those of the Bracken (Pteris aquilina], or divided to any intermediate extent. The sporanges are borne in clusters (sori} of various kinds on the back or the margins of the frond, and are usually placed above a vascular bundle. The sorus is often protected by an indusium, which is an outgrowth from the epiderm and may be two-valved, cup-shaped, linear, hood-like, buckler-shaped, kidney-shaped, or a con- tinuation of the frond margin. In some species the sori are produced on special fronds, which may differ in appearance from the barren fronds, as is the case with FIG. 642.— FERN-SPOKES GERMINATING. our Hard Fern (Lomaria spicant, fig. 637) The first figure shows the shoot with rootlet and Parsley Fern (Cryptogramme crispa). bursting through theexospore. The second shows €/. . , *^ r a more advanced stage, and the division of cells In germination the exospore bursts and toformtheprothaiiium. HIDDEN MARRIAGES 505 FIG. 643. — AN AKCHEGONIUM. An organ on the under side of the prothallium in which, after fertilization, the young fern-bud is produced. the contents by growth and division rapidly develop into a minute green heart- shaped scale (prothallium'), with a depres- sion of the anterior margin, in which the growing point is seated. The prothallium as a whole consists of a single layer of cells, but behind the growing point a cushion of several layers is formed, from one part of which root-hairs are produced. On a portion of the cushion clear of root- hairs the archegones will be found, and among the root-hairs or on the margins are the antherids. Cystopteris fragilis pro- duces prothallia of two kinds, a smaller bearing antherids only, and a larger bear- ing both antherids and archegones. The prothallia of Gymnogramme bear antherids at first and archegones appear later (fig. 641). Each antherid contains compara- tively few antherozoids, each being ribbon-shaped, coiled three or four times, with a number of fine cilia at the fore end. The archegones have a curved neck with a canal leading to the oosphere. The canal is formed by the breaking up of a central row of cells whose walls and contents dis- solve into mucilage, which is expelled and serves to retain the anthero- zoids, which then make their way into the canal, some of them reaching the oosphere and fertilizing it. Only one archegone on a prothallium is fertilized ; and on many prothallia no fer- tilization takes place. In some varieties of Athyrium filix-fcemina and Aspidium angulare prothallia bearing normal anthe- rids and archegones are produced on the fronds. The phenomenon is known as apospory or suppression of the asexual generation. Certain species of Asplenium and Cystopteris produce buds on the fronds, which grow into little plants without anv fertilization. In Polypodiacese, which comprises most of our native genera, the sporanges have foot-stalks ; in all or nearly all the other orders they are sessile. Each spor- ange has originated in a single cell of the epiderm. It is a round, oval, or pear- FIG. 644.— AN ANTHERIDIUM. shaped capsule, and when mature the walls Antherozoids escaping. 506 HUTCHINSON'S POPULAR BOTANY FIG. 645. — CUP-SHATED IN- DTJSIUM OF FILMY FERN (Hy- menophyllum), and the same in section. consist of a single layer of cells. A longitudinal row of these cells, known collectively as the annulus, have thickened borders. From two to four others, known as lip-cells, have lignified walls ; it is between these lip-cells that the dehiscence or rupture of the sporange begins. This is brought about by the drying and consequent un- equal contraction of the cells of the annulus, which pulls the lip-cells apart ; following their separation the sporange splits across and scatters the spores. The annulus does not form a com- plete ring in this order. Frequently from the foot-stalk of the sporange in Polypodiacese there is a hair-like outgrowth — a paraphyse. There are normally sixty-four spores in each sporange of this order, produced in the usual way by division of the archespore into mother-cells and subdivision of each of these into four spores. In the Family Hymenophyllese (Filmy Ferns) there is usually a creep- ing stem, and the fronds are very thin and translucent, the mesophyll consisting of one layer of cells only. The indusium is cup-shaped (fig. 645). The fertile vein projects beyond the edge of the frond, and a prolongation of it called the columel extends into the centre of the indusium, where the sporanges are borne spirally upon it. Instead of being seated on a foot- stalk as in Polypodiacese, they are attached to the columel by one of the two convex faces. The annulus is complete. The spore undergoes division into three cells before the rupture of the exospore, two of which soon cease to develop, but the third increases greatly in length, divides transversely, and puts out thread-like lateral shoots, from which flat prothallia are produced. As will be seen later, this form of prothallium approximates to the protoneme of Mosses, and as the order contains the simplest of the ferns it may be that it marks a stage in their evolution from the Mosses. The aiitherids will be found about the middle of these filaments, the archegones at the extremity. The phenomenon of apogamy — the substitution of a vegetative for a sexual mode of reproduction — occurs frequently in this order, and it is thought may be quite usual in certain species. Little foot-stalks (sterigmas) produced from the prothallium bear bulbils of a few cells which slowly germinate and grow into sporophytes without any process of fertili- zation. All the species in this order are of exceedingly delicate texture, and can only endure a moist warm atmosphere. The fronds are without stomata. FIG. 646. — ANTHEROZOIDS. (a) Antherozoid in mother-cell. (6) Antherozoids escaped from cells. IE. Step. FIG. 647. — PRICKLY BUCKLER FERN (Nephrodium spinulosum). A common fern of graceful habit in old woods where the leaf-mould is deep. 507 608 HUTCHINSON'S POPULAR BOTANY The Order Osmundacese is deficient in the indusium, and the annulus is very greatly modified. The sporanges are borne on certain of the pinnules of the fertile frond of which the mesophyll is partly or entirely undeveloped, so that only the sporanges thickly clustered round the midrib are visible. The sporange is not symmetrical ; in some species it is shortly stalked, in others sessile. The in- complete contracted annulus is near the apex on one side, and at a little distance from this the sporange splits vertically. The prothallium exhibits a tendency to become direcious ; sometimes all the spores from one sporange produce prothallia that bear antherids only, or archegones only. Some prothallia bear antherids first and archegones later. Often the pro- thallium throws out adventitious shoots, and so propagates itself vegetatively. In all these orders of Ferns the verna- tion is circinate, the frond and its divisions being rolled up from the apex. The genera Ophioglossum and Uotrychium, often in- cluded in the Class Filices, differ from them in this respect among other differences, their fronds in the incipient stage being folded from the sides. These genera are, therefore, elevated into a separate class, the Ophioglossacese. The upright stem produces only a few leathery fronds, often only one frond. The rachis of the frond is furnished at the base with scaly out- growths, like the so-called stipules found in a tropical order of ferns, the Marattiacese. When the rachis has attained half its final length, it forks, one branch developing into a smooth leafy expansion, furnished with stomates on both surfaces, the other becoming the sporophyll bearing the closed sporanges. These fronds are of very slow growth ; in our Moonwort (Botryckium lun-' aria, fig. 648), for example, they do not appear above ground until four years after the formation of the bud, their expansion marking their fifth year. The root-stocks are poorly developed, bearing thick fieshy root- FIG. 648.— MOONWORT (Botrychium lunaria). One branch of the frond bears the sporangia, (a) Closed sporanges enlarged. HIDDEN MARRIAGES 509 FIG. 649. — PILLWORT. One of the sporocarps enlarged. fibres without root-hairs ; those of Adders-tongue (Ophioglossum vidgatum] put forth adventitious buds. As we have seen, in the Polypodiaceae each sporange is formed from a single cell of the epi- derm ; but in the Ophioglossacese a single sporange is the product of a group of specialized cells be- neath the epiderm, and is therefore more homolo- gous to an entire sorus in the true ferns. Its walls, several cells thick, are products of the epiderm, and are still furnished with stomates. Their full development occupies a year, and they are then globose in shape, have no annulus, and split transversely to liberate the minute squarish spores. Instead of germinating on the surface as do the spores of ferns, these appear to need burial before developing into pro- thallia; at least, so far as it has been observed, the prothallium is a subter- ranean tuberous body, devoid of chloro- phyll, and bearing archegones and ^ antherids seated in pits or projections of the upper surface — the former in Botry- chium, the latter in Ophioglossum. These organs and their contents are very similar to those of ferns. The Order Hydropteridese, or Water- ferns, is a small group consisting of few genera and species, with a solitary British representative, the Pillwort (Pilularia globulifera, fig. 650). They are aquatic or semi-aquatic plants, and the spore-cases (sporocarps} are borne at the base of the leaves. The Pillwort, which grows on the margins of lakes and ponds where it is sub- merged in winter and exposed in summer, consists of a creeping stem from the under side of which are produced at intervals small tufts of fibrous roots, and from the upper surface erect, cylindrical, bristle-like bright green leaves, in whose axils are the short- stalked, globular sporocarps. These sporo- carps, which have a hard shell of scleren- chyma, are divided into four compartments, and in each of these, springing from the broadest face of the wall, is a cushion an- alogous to the placenta in the ovary of FIG. 650. — PILLWORT (Pilularia globulifera). Portion of plant showing sporocarps the fronds. 510 HUTCHINSON'S POPULAR BOTANY Phanerogams, to which are attached megasporanges containing one large spore, and microsporanges containing a large number of small spores. The sporanges attached to each placenta constitute a sorus. The mega- sporanges are chiefly the lower bodies of the sorus, and although at an early stage of development the contents of each becomes broken up into sixty-four cells, only one of these becomes mature and develops into a megaspore. Each microsporange, however, produces sixty-four micro- spores. The megaspore becomes invested, first, in a hard brown coat, but later this receives an outer gelatinous coat — the epispore — consisting of three layers, except at the apex of the spore where the two outer layers are wanting, and the apex in consequence lies in a cavity whose walls are the two outer layers of the epispore. At the apex the protoplasm breaks up into several cells, which are not at first invested by cellulose, but finally form a tissue containing a little chlorophyll and developing into a prothallium. The growth of the latter causes it to break through the apical layers of the megaspore and project as a spherical body into the cavity previously referred to. In the centre of the prothallium there is a large cell (afterwards the archegone) covered by four other cells, from which arise the neck and stigmatic cells of the archegone. The greater portion of the protoplasm of the archegone contracts into an oosphere (fig. 643). Each microspore divides into three cells, of which one becomes a sterile prothallium, but each of the other two divides into sixteen cells, and the nucleus of each of these becomes an antherozoid—a rod-like body coiled four or five times, to which are attached a few cilia, by whose vibration the body is impelled. The anthero- zoids find their way to the funnel above the apex of the megaspore, and getting entrance by the neck of the archegone, reach the oosphere and fertilize it. The result of this fertilization is the development of the oosphere into an oosperm, which becomes invested with cellulose and undergoes segmentation to form the embryo with its root, stem, first leaf, and an attachment (foot) to the prothallium. Thus arises the sporophyte like that by which the sporocarps were produced. The " leaves " of Pilularia consist only of the petiole, no lamina being developed. In the early stages these leaves are coiled up from the apex to the base, FIG. 651.— PILLWORT (Pilularia globulifera). A diagrammatic section of one of the sporocarps, showinR clusters of megasporanges and microsporanges in each of the four compartments. IE. Step. FIG. 652. — SEA FERN (Asplenium marinum). A fern with thick, leathery fronds, that grows oniy on maritime rocks, and chiefly over the entrances to cav 511 512 HUTCHINSON'S POPULAR BOTANY FIG. 653. — PILIAVORT. and gradually unroll as they grow to their full size. Marsilea, which grows in similar situations to Pilularia, but does not occur in this country, has a quatrefoil leaf, the segments of which fold together towards night and expand again in the morning, thus agreeing in its sensitiveness to light with the leaves of Oxalis and other trefoils among Phanerogams. The Class Equisetinse, or Horsetails, consists of the order Equisetaceas and a single genus, Equi- setum, of erect, hollow-stemmed, jointed, and leaf- less plants. The leaves are represented by the one of the microstores. teeth of the sheath in which each node terminates. The branches, where present, are jointed, but, unlike the stem, are solid, and spring from the base of the sheath. The stems are ridged and grooved longitudinally, each species having a characteristic number and form of ridges, and the sheath-teeth correspond with them. In some species there are barren and fertile stems, the latter being without branches and almost or entirely devoid of chlorophyll. Silica is deposited abundantly in the cell- walls of the cuticle, and in consequence several species have long been used under the name of Dutch Rushes for scouring and, polishing metal. So abundant is this mineral that all the vegetable matter may be burnt out without affecting the form of the structure. Stems and branches alike are provided with stomates and chlorophyll, and can carry on the functions of the absent leaves. The fertile stems bear at their extremity a cone-like spike of sporange- bearing discs. These discs or scales are the sporophylls ; they are many- sided (usually hexagonal), supported on a central foot-stalk, and bear on the under side from five to ten sporanges. The sporophylls are arranged in whorls corresponding with the sheaths, and prob- ably, like them, are modified leaves. Be- tween the uppermost developed sheath and the lowest whorl of sporophylls there is an undeveloped sheath forming an in- volucre to the fruit-spike. The sporange has no annulus, and opens by a longi- tudinal fissure to set free the spherical spores, which differ from those of ferns in having four coats, the outer of which splits up spirally into four strips with broader ends, known as elaters (fig. 654). These elaters are highly hygroscopic, and FIG. 654. — HORSETAIL (Eguisetum). (a) Spore with elaters coiled around it. (6) The same with the elaters extended. A representative of a large The minute flowers are borne in glob small, nearly smooth le TOOTH Kl) CEANOTHUS (Ceanoth f Americ an shrubs, of which several have found favour in our gardens as wall plants, clusters and are either some shade of blue or white. The present species has with toothed edges. It is a native of California and Oregon. HIDDEN MARRIAGES 513 as they dry they stretch out from the spore ; but on the air becoming moist, they contract, and twist around the spore. If a slide of these spores be breathed upon and then viewed through the microscope, they will be seen to leap about as they dry. Another difference between these and fern- spores is found in their possession of chlorophyll. Fern-spores with few exceptions are devoid of this important substance, and if kept dry will retain their vitality, in some species, for several years ; but chlorophyll will not keep, and unless the spores of Equisetacese are placed under such conditions as to induce germination, they perish within a few days of their dispersion. If the proper conditions are present, germination is very rapid — a matter of a few hours only. The prothallia are commonly dioecious —that is, the archegones are borne on a different prothallium from that which bears the antherids, but a few organs of the opposite sex are often produced at a later date. They are very much longer than broad, and the newest portion is much broader than the old. The less vigorous prothallia are male, the more vigorous female; both are lobed at their anterior margin, but the lobes of the females are long strap-shaped extensions. Both forms are found in '. Step. FIG. 655. — PILLWOBT (Pilularia globulifera). this plant grows in such quantities that it might be mistaken for a kind of grass, portion of such a colony is here shown. 514 HUTCHINSON'S POPULAR BOTANY close proximity, so that the antherozoids can easily pass to the archegones by the aid of the moisture that condenses upon the prothallium. The sexual organs and their contents are very similar to those of the ferns. After fertilization of the oosperm and formation of the embryo, minute stems are produced, differing in little except stature from the mature stems, and an underground perennial rhizome is also developed. In some species \E. Step. Fia. 656. — FIELD HORSETAIL (Equisetum arvense). Fertile stems bearing the cones, which appear in advance of the much taller and branched barren stems. The latter are shown in Fig. 657 on the opposite page. there is a vegetative propagation by the formation of tubers on the rhizome and the bases of the stems, in which starch, etc., is stored. The Class Lycopodinse consists of the Orders Lycopodiacese and Selagi- nellacese. In the former the typical genus Lycopodium is represented in Britain by five species of Club Mosses, so-called because in some species the sporophylls are crowded together on special erect branches which, from being stouter than the stem immediately below them, have a club-like Photo by] IE. Step. FIG. 657. — FIELD HORSETAIL (Equiaetum arvenae). The barren fronds which grow to a height of two or three feet present a strong contrast to the fertile spikes shown on the previous page. Here there are whorls of long, jointed branches from base to summit. NORTH EUKOPE, NORTH ASIA, NORTH AFRICA, the HIMALAYA, and NORTH AMERICA. 515 516 HUTCHINSON'S POPULAR BOTANY appearance. There is usually a rigid wiry stem which forks repeatedly, and is covered with overlapping small undivided leaves, which either invest the stem all round or are arranged in from two to six rows. Some exotic species have erect stems, and of these certain tropical ones are stout arid shrubby. Several have even become climbers, and a few have given up their connection with the earth and grow only upon trees (epiphytic}. The kidney-shaped sporange is attached by a short stout foot-stalk to the base of the upper side of the sporophyll or leaf. It is one-celled, and Photo by] IE. Step. FIG. 658. — MARSH CLUB Moss (Lycopodium inundatum). This species is leas noticeable than the others, from its habit of keeping close to the soil in marshy places, and from the shortness of its stems which die back in winter. The fertile branches are erect and end in slightly thickened cones, which are evident in summer. splits when ripe into two valves. The numerous spores are more or less rounded, marked with three radiating lines on the upper side, and on germinating, the exospore splits along these lines into three valves, from which the endospore projects and grows into the germinating filament. A transverse wall (septum) develops across the filament and divides it into a small basal cell and a larger apical cell. No further change occurs in the basal cell, but the apical one divides into two series of cells, and each of these cells afterwards divides into two. Each cell is provided with a few grains of chlorophyll, except in Lycopodium annotinum, whose HIDDEN MARRIAGES 517 prothallium, being buried, is destitute of chlorophyll, and yellowish white in colour. Archegones and antherids are produced in close proximity upon the upper side of the prothallium. The antherozoids are minute, consisting of only a few coils and, so far as at present observed, a couple of cilia. Apparently only one archegone is fertilized on each prothallium. Very little is known of the early stages of growth in the sporophyte, but there is reason for believing that it follows a similar course to that of the Ferns. Under the name of Lycopodium powder the spores have been used in mass for coating pills, being damp proof ; and in Vegetable Brimstone. They also have their use in dyeing. The Club Mosses, with the exception of the Marsh Club Moss (Lycopodium inundatum), are found on elevated moorlands, chiefly in the north ; the Marsh species comes farther south, and is found on swampy heaths and around bogs. It forms creeping branched shoots of only a few inches in length, and some of the branches take a vertical direction of growth. These are quite stout and bear sporophylls. The Common Club Moss (Lycopodium davatum] extends for several feet, and throws up numerous erect branches with the clubbed extremity which gives the popular and expressive name to the group. But the club appearance is not so much due to any real greater stoutness of the upper part as to the fact that the leaves for a short distance below are less spreading, and have their upper faces more closely pressed to the stem. This gives a more slender appearance to this part, and enhances the slight advantage the club has in circumference. The Fir Club Moss (Lycopodium selago) is a con- spicuous object on northern mountains, though it also occurs sparingly upon high FIG. 659. — LESSER ALPINE CLUB Moss (Selaginella selaginoides). Microsporange to the right, and megasporange to the left of stem. pyrotechny they are known as FIG. 660. — COMMON CLTTB Moss (Lycopodium clavatum). 0) Spikes or cones, (a) Fertile leaf or sporo- phyll with sporange, (sp) Spore. 518 HUTCHINSON'S POPULAR BOTANY ground as far south, as Cornwall and Sussex. It has been likened to a fir-tree in miniature, but it might easily be mistaken for an early condition of a coniferous seedling. It has little of the clubbed character, and it does not creep. All its shoots take an upward direction, and it therefore forms bushy clumps. In common with those of several other species, some of the lower leaves of the cone produce buds instead of sporanges, and these separate and fall to the ground, where they develop directly into plants without the interven- tion of the prothallium stage. The Order Selaginellacese consists of the two genera Selaginella and Isoetes, both of which are represented by British species. Both megaspores and microspores are pro- duced, but in a manner different from those of the Water-ferns, and the prothallium is quite devoid of chlorophyll. Our only native species of Selaginella is the Lesser Alpine Club Moss (Selaginella selaginoides), a small moss-like plant inhabiting bogs and marshes. Several of the numerous exotic species are well known in our conserva- tories and greenhouses. S. selaginoides has creeping stems only a few inches long and completely clothed all round with overlap- ping lance-shaped leaves. A few branches are of more erect growth, and the leaves of these are longer, more closely pressed to the stem, which ends in a stouter scaly cone about an inch long. This cone is the part of the plant that bears the spor- angia, and the leaf-like scales containing them are known as sporophylls. The spor- ange, on a short stalk, springs from the stem just above the base of the sporo- phyll. Those in the lower sporophylls are spherical and megasporanges ; in the upper sporophylls, there are flattened micro- sporanges (fig. 659). Each megasporange contains only three or four megaspores, which are set free by the splitting of the sporange into three or four valves; the microsporanges are only two-valved, and their contents are minute and numerous. Both kinds of spores are invested by three coats — endospore, exospore, and epispore. The growth of the pro- thallium within the apical portion of the megaspore proceeds pari passu with the development of the larger body, whilst the protoplasm which FIG. 1. — QTJILLWOBT (Isoetes lacustris). (a) Leaf with sporange in base, (b) Base of leaf on larger scale, (c) Transverse section through ripe sporange, showing spores. IE. Step. Fia. 662. — GREAT ~H.ORSErrA.nJ_(Equisetum maximum). This is a much stouter and taller plant than the other native species, attaining to a height of six feet or more, the white stem with a diameter of half an inch . The fertile stem is even stouter, but seldom more than a foot in length. EUROPE, NORTH AND WEST ASIA, NORTH AFRICA, and NORTH AMERICA. 519 520 HUTCHINSON'S POPULAR BOTANY fills the greater portion of the spore is being converted into a cellular tissue variously designated the secondary prothallium and endosperm. The archegones are produced on the surface of the prothallium, some of them being already present when the latter is extruded from the megaspore. There is a neck with its canal leading to the interior with its oosphere. The microspores are coloured red or orange, <\nd although development begins in the sporangia through- out the winter, they appear to make no advance upon their con- dition when set free. In spring, however, fresh activity is mani- fested, and one portion of the proto- plasm becomes an antherid, some of whose numerous cells contain coiled antherozoids with two long cilia attached to the tapering fore- part. For half an hour or so after the rupture of the mother-cells the antherozoids are endowed with motion, and find their way by the neck canal to the oosphere. Thus fertilized, the oosphere develops into an embryo with a pair of primary leaves, a root, and a foot or organ of absorption. The Prickly Club Moss (Sela- gine.lla selaginoides) is found in swampy situations, chiefly on moun- tain-sides, not farther south than Wales. Its slender stem is not more than six inches in length. It creeps along the ground, but the fertile branches which bear the sporanges rise erectly, and end in a cone with larger leaves (sporophylls). The genus Isoetes is represented in this country by a single species, the Quillwort (Isoetes lacustris}. Though the plants of Quillwort and Selaginella are as unlike as possible, the developmental history of the embryo is very similar to what we have just described. The Quillwort grows at the bottom of lakes among the mountains of the northern half of Britain, and its stem takes the form of a corm whose increase is not so much in length as in diameter. The leaves are awl-shaped, with broad overlapping bases which entirely hide the corm and in which the sporanges are produced. The outer leaves bear mega- FIG. 663. — HAIR Moss (Polytrichum commune). (aa) Antheridii. (bb) Hairs and sterile filaments (paraph yses). HIDDEN MARRIAGES 521 sporanges, the inner ones microsporanges (fig. 661). A second species, 1. hystrix, found in Guernsey, is of terrestrial habit, growing on sandy soil which is only occasionally inundated. In this Order the prothallium is not nearly so precocious as in Selaginella. The megasporange decays and sets free the megaspore, and it is not until several weeks later that the contents become converted into cellular tissue. Then the epispore breaks up by a three-rayed fissure at its apex, and the rupture of the endospore follows, exposing part of the prothallium, which is in this case spherical. Photo fty] IE. Step FIG. 664. — SCREW Moss (Tortula subulata). A moss common on wall tops and woodland banks. The curved cylindrical capsules are borne on long, bristle-like stalks, and the peristome is spirally twisted so as to resemble a screw. An archegone appears at its apex, very similar to that of Selaginella, and if this becomes fertilized no other is produced ; but in the event of failure, others appear until fertilization of one is effected. The microspores are three-sided and ultimately contain long, slender, and spirally coiled antherozoids, which taper to a fine point at each end, where numerous cilia of great length are produced. The swarming period is only a matter of a few minutes, the antherozoids finding their way to the oosphere by the neck canal as in Selaginella. 522 HUTCHINSON'S POPULAR BOTANY FIG 665. — LIVERWORT (Marchantia polymorpha ) . With antheridial receptacles. We now come to those Cryptogams in which the structure is entirely cellular, the first division of which is the BRYOPHYTA. Class I. Musci. Mosses. „ II. Hepaticse. Liverworts and Scale Mosses. In these classes we find an alternation of generations, as in the Pteridophyta, but there is a difference to be explained. Beginning with the spore, we find it to consist of a central mass of protoplasm, in which are chlorophyll-grains, etc., in- vested by an inner coat or endospore, and an outer coat, or exospore. On germinating, the endospore and its contents burst through the exospore and develop into a hair-like body — the protoneme. Side shoots from the protoneme develop into chlorophyllous scales in the Liverworts, and into leafy stems in the Mosses. These in turn bear sexual organs — archegones and antherids (figs. 665, 666). In the protoneme of the Mosses cell-division takes place in one direction only — transversely ; but as this may go on indefinitely, we have the fila- mentous form. Some of the cells thus formed send out lateral shoots which in turn divide transversely, so that the protoneme may be ultimately many- branched. Distinct buds are also produced which develop into wiry stems, which are clothed with two, three, or four rows of leaves. The protoneme and this leafy plant produced by it must be considered as together constituting the oophyte or sexual generation. The leaves of Mosses are never stalked, and with the exception of a line down the centre (midrib), and in most cases along the margins, consist of a single layer of cells ; stomates being therefore unnecessary, the leaves have none ; but the stem is often liberally pro- vided with stomates. The midrib is not always continued to the tip of the leaf ; on the other hand, in many species it extends ^^^K^jHfV* beyond the tip as a fine hair-like point of variable length. Around the three-sided apex of the stem the leaves are more densely crowded, and these are more or less modified. They constitute the peri- FlG. 3. — LIVERWORT. With archegonial receptacle, (a) Cup-shaped receptacle containing gemma?. 523 524 HUTCHINSON'S POPULAR BOTANY chaete, popularly but incorrectly known as the " flower " of the Moss. These " flowers " are of three kinds : first, containing antherids only ; second, con- taining archegones only ; and third, containing both antherids and archegones. Sometimes the.se occur on the same plant, in some species on different plants. Where the sexes are thus separated the plant is said to be dioecious, where the two sexes are on the same plant the latter is monoecious ; and when one " flower " contains both antherids and archegones it is her- maphrodite. The male flower (penrigone) may be distinguished by its broader and thicker leaves. Among the sexual organs are a number of thread-like or club-shaped bodies known as paraphyses. The antherid when mature consists of a foot-stalk bearing a club-shaped (sometimes spherical) head, which opens at the apex or splits down the sides, freeing a large number of minute cells, in each of which is coiled a long antherozoid, tapering forwards, at which extremity it is pro- vided with two long cilia (fig. 663). The anthero- zoids swim about in the mucilaginous fluid which accompanies their expul- sion and make their way to the archegones. The latter consist of a swollen basal portion, in which is the oosphere, and a long, slender neck, pierced by a canal, the mouth of which is guarded until maturity by a couple of lid-cells (the stigma]. At maturity, a quantity of mucilage being ejected from the canal, the lid-cells are forced apart, and the way is open for the entrance of the antherozoids. As a rule, only one oosphere in a " flower" is fertilized and becomes an oosperm. This develops into the sporogone or asexual generation, which, until it perishes, always remains attached to the sexual generation and is nourished by it. The growth of the sporogone ruptures the arche- gone transversely and stands revealed as the stalked capsule of the Moss containing the spores. The remains of the ruptured archegone become the vagine or sheath below the capsule, and the calypter or cap above it. This calypter is, as a rule, of very thin, chaffy material, and is thrown off by the expansion of the capsule, much as the similar bud-scales are thrown off by the expansion of the buds of trees and shrubs in spring. In the Common Hair Moss (Polytrickum) the calypter is thick and shaggy, consisting of long hair-like scales of a pale golden hue, which makes the FIG. 668. — Plagiochila asplenioides, A SCALE Moss. The general character of these plants is here shown — the creeping stem with its delicate leaves arranged in one plane, and the terminal fruits, one intact and the other after it has burst to discharge its spores. HIDDEN MARRIAGES 525 patches of this moss a very noticeable feature of the heaths where it grows in abundance, and often to a considerable height — for a moss, that is. When the sporange is freed from the vagine and the calypter, we can see that it has a distinct lid or opercule, which is thrown off to allow the escape of the spores. When this is lifted off, the sporange will be found to have either a smooth rim around its mouth (gymnostomous), or it bears a peristome — a single or double series of slender appendages, the inner row being cilia, the outer row teeth, whose number is always some multiple of four. The peristome is hygroscopic. When the atmo- sphere is dry, the teeth or cilia stand away from the mouth and allow the dispersion of the spores ; in damp weather they close the orifice and keep the spores dry. A very common species that exhibits this hygro- Photo by} FIG. 669. — Two MOSSES. That to the left is the very common Cord Moss (Funaria hygrometrica) which comes up wherever vegetable matter has been burnt on the ground. The clump to the right is the Convolute Screw Moss (Torlula convoluta). metrism well under a low power of the microscope is the Cord Moss (Funaria hygrometrica) that forms a continuous carpet over the charred earth wherever there has been a heath fire. A better example for those who work with the pocket-lens rather than the iCompound microscope will be found among the Screw Mosses (Tortula) that cover the tops of old walls. One such is shown in fig. 664, where the comparatively long and cylindrical capsules will be seen supported on long bristle-like stalks. The teeth of the peristome are in this genus very long, and when closed they are coiled spirally. The entire peristome then presents the appearance of a reddish screw, which fact has suggested the name of Screw Moss. In Polytrichum, in which the teeth are short, there is another piece of mechanism to the same end. Beneath the opercule the mouth of the 526 HUTCHINSON'S POPULAR BOTANY sporange is closed by an epiphragm supported on a central pillar, the columel, which rises from the base of the sporange. The wall of the sporange contracting in dry weather brings the epiphragm half-way up the peristome, thus allowing the spores to sift out between the teeth. In damp weather, with the elongation of the sporange, the epiphragm again comes to the base of the peristome and the orifices are closed. In the Order Phascacese the sporange does not dehisce at all, and the spores are only liberated by the decay of the walls. In Andreaceae, again, there is no opercule, but four or eight slits appear in the spor- ange wall, from below the summit to near the base. In addition to this sexual pro- cess, Mosses may be produced vegeta- tively by throwing off little buds, which root and develop into perfect plants. In some of our native species this is the only method of reproduction, the sporangia never being produced. In the Liverworts and Scale Mosses we find two distinct types — a more or less flat green scale like a large fern pro- thallium, and a delicate plant with a well- marked differentiation into stem and leaves. Species that conform to the first type are known as Thalloid Hepatics ; such as answer the second description are Foliose Hepatics. Both forms are entirely cellular, and are attached to the soil by root-hairs. The process of reproduction is similar to what we have seen in the Mosses, in that the spore gives rise to a protoneme from which the sexual gener- ation is developed. The mode of bearing the sexual organs differs in various orders and genera. They may be produced from the growing point of the main stem or branches of the Foliose forms ; in the substance or on the upper surface of the Thalloid forms, and in Marchantiacese on a special stalked outgrowth of the thallus, and known as the antheridiophore or the archegoniophore, according to sex (figs. 665, 666). Both organs may be produced by one plant (monoecious}, or they may be on separate plants (dioecious). These sexual organs originate in little swellings, which afterwards are seated each on its own little foot-stalk. The antherid splits irregularly and sets free a number of cells, each containing a spirally coiled, ciliated antherozoid. FIG. 670. — LIVERWORT (Marchantia polymorpha). An archegonium. Photo by] [E. Step. FIG. 671. — A LICHEN (Evernia prunastri). Common on the bark and branches of trees, particularly on blackthorn and firs. Its pale greenish-grey branches are always more or less drooping. 527 528 HUTGHINSON'S POPULAR BOTANY The archegone has an enlarged lower portion containing the oosphere, and an upper neck with its canal, through which the antherozoids gain access to the oosphere. After fertilization the oosphere develops into the sporogone, usually elevated on its stalk, which carries it up through the calypter ; this is the entire non-sexual generation. In Riccia the sporogone is immersed in the thallus. Among the spores are long attenuated cellular bodies, the elaters, whose walls are furnished with spirally twisted threads, which are hygrometric and cause the twisting of the elaters as they absorb or part with moisture. Their movements under this influence assist in the dispersal of the spores. The spores may be invested in one, two, or three coats, but usually two. The popular name Liver- wort, applied to the larger and more conspicuous mem- bers of this class, is, as its Saxon termination shows, an old folk-name. The ap- pearance of the epidermal cells and the shape of the fronds were supposed to be in little a picture of the human liver, and to indicate under the Doctrine of Sig- natures that it was to be used as a medicine in liver troubles. As late as the middle of the seventeenth century we find Nicholas Culpeper, who was great on Signatures, describing the vhich is shown more highly magnified in the second figure. The round T ilVPrwnrt flQ " n ciri mild Y- and oval forms between the hyphce represent the algal elements. Ljl^ erWOr a Singular good herb for all the diseases of the liver, both to cool and to cleanse it, and helpeth the inflammations in any part, and the yellow jaundice likewise," and ." an excellent remedy for such whose livers are corrupted by surfeits, which cause their bodies to break out, for it fortifieth the liver exceedingly, and makes it impregnable." It had to be " bruised and boiled in small beer and drank," but with the happy-go-lucky methods of prescribing in his day, he omits to say whether a dose consisted of a tablespoonful or a quart. The open-air exercise involved in a search for the numerous species would probably do far more to keep the liver normal than a barrel of Culpeper's small beer in which Marchantia polymorpha had been boiled. More than two hundred and sixty species of the Hepaticse are known to inhabit the British Islands, and though they are all comparatively small plants, they are in FIG. 672. — SECTIONS THROUGH LICHEN. In the left-hand figure the loose hyj. rkc.l the gonidial layer, HIDDEN MARRIAGES 529 most cases characterized by great beauty and delicacy of form. The leafy Scale-mosses are of a more delicate structure than most Mosses, their leaves being filmy and al- most transparent, which is due to the cells being larger and the cell-walls thinner. The stems are more ad- dicted to creeping, and the leaves are mostly all in the same plane. They are shade and moisture-loving plants, and must be sought in the damp shade of woods, on the rocks and margins of mountain streams, the banks of ditches, the swamp3r borders of pools. As an example of these foliose Crystalwortswe give a figure of PlagiochUa as- plenioides (fig. 668), a species that may be found growing at the base of tree trunks in moist woods. The toothed leaves are arranged pinnately along the two sides of the stem, and the fruit is borne at the extremity of the branches. As drawn, the leaves show a central division or fold, and this must not be taken for a nerve, for in all the Crystal- worts the nerve, so con- spicuous a feature in the leaves of Mosses and higher Photo by} [/? plants, is entirely wanting. FIG. 673.— BEARD Moss (Usnea dasypoga). Of the two fruits shown A delicate grey Lichen that hangs in lengths of a foot or more from old ' forest trees. that to the right has the sporange intact ; that to the left has split into its four valves which spread out to release the spores. n—16 530 HUTCHINSON'S POPULAR BOTANY The remaining classes of Cellular Cryptogams are grouped under the divisional name of THALLOPHYTA. Class I. Fungi. „ II. Characeae. Stoneworts. „ III. Rhodophyceae. Red Algae. „ IV. Phaiophyceae. Brown Algae. „ V. Chloropliyceae. Green Algae. Class VI. Conjugatae. Conjugates. „ VII. Peridineae. Dinoflagellates. ,, VIII. Diatomeae. Diatoms. „ IX. Schizophyta. Fission Plants. „ X. Myxotnycetes. Slime Fungi. FIG. 674. — CUP Moss (Cladonia pyxidata). [E. Step. imiliar Lichen common on banks. The trumpet-shaped cups spring from a small flat thallus jar apothecii around their mouths. The plants of the first class, the Fungi, are characterized by a total absence of chlorophyll and starch. Two distinct portions of a fungus are recognized, the vegetative or mycele, and the reproductive or sporopkore. That to which we apply the term "mushroom" or "toadstool" is the sporo- phore ; the mycele consists of a network of white threads ramifying in the vegetable humus below. Fungi have no roots, properly speaking, though the mycele fulfils their office, both as absorbers of nutriment and for purposes of attachment. As they possess no chlorophyll, they are unable to decompose carbon dioxide, and therefore have to obtain their carbon in an already organized condition. This they get from dead or decaying plants and animals or from organic products, or by attacking living! organisms. Photo by] FIG. 675. — Ramalina scopulorwn. A. Lichen that grows— among other places— on maritime rocks only a few inches above high-water mark. The photograph shows it growing in such a situation with a narrow channel of sea-water flowing between. .531 532 HUTCHINSON'S POPULAR BOTANY Species that perform the latter operation are classed as parasites; those that content themselves with organic remains are saprophytes. Members of either class that have the power during the whole or part of their life of performing the functions of the other class are qualified as facul- tative saprophytes or parasites, as the case may be. Another group live symbiotically with algse, and are known as lichen-forming fungi — Lichens, formerly considered as a distinct subdivision of Cryptogams, being now known as compounds of fungal and algal elements (figs. 671-675). As the Fungus is obviously the dominant partner in this joint-stock company, it is usual to treat of Lichens under the head of Fungi, but from the field naturalist's point of view it is still convenient to consider them as though they were simple organisms, and to retain their distinctive names. Many of them are among the most beautiful of our crypto- gamic plants, and adorn what they grow upon, whether it be an old wall, an alpine rock, the trunk or branch of a tree, or the bare earth of moor or woodland. These differences of situation adopted by the various so- called species produce great variety of form and habit, some sitting so closely that they might be regarded as mere stains or dabs of paint. Others spread out flat branching lobes or hang as grey beards from trees, and some spread over the ground or grow up from it like miniature shrubs. Among the latter are the Reindeer Moss (Cladonia rangiferina, fig. 104), and the pretty Cup Mosses of the same genus (fig. 674). The Dog Lichen (Peltigera canina, fig. 677) spreads along the ground, forming patches five or six inches in diameter, much like a large Liverwort, but of a more leathery texture. Its names are accounted for by the fact that in former days it was considered a specific for hydrophobia. This belief may have been due, under the " Doctrine of Signatures," to the dog-tooth-like appearance of the fruits along the margin of the lobes. The herbalists called it Ground Liverwort, under the im- pression that it was a kind of Marchantia. A similar " signature " caused the prescription of the Lichen known as Lungs of Oak (Sticta pulmonaria) in pulmonary troubles, the pitted underside being supposed to resemble the structure of the lungs and so to indicate its suitability for mending them FIG. 676. — POTATO-BLIGHT (Phytophthora infestans). One of the Phycomyceteae. At (a) the hypha is seen growing out through a stomate of Potato leaf and bearing sporanges. (6) Zoospores. (c) A germinating zoospore. HIDDEN MARRIAGES 533 when diseased. Many of the Lichens have long been extensively used in the art of dyeing. The Reindeer Moss already referred to is of the utmost value to the wandering Laplander, who feeds his domestic herds upon it during the winter. The Reindeer are said to know where it is growing under the snow, which they scrape away with their antlers. The Icelander makes similar use, not only for his cattle, but for himself also, of another Lichen, the Iceland Moss (Cetrarla islandica), which at one time had a great Photo by] [E. Step. FIG. 677. — DOG LICHEN (Peltigera canwa). One of the largest of the Lichens. It grows upon the ground and resembles a Liverwort on a large scale. The fruits of a pale-brown colour, with incurved margins, spring from the edge of the thallus. vogue in this country as a food for invalids, and still retains a place in the British Pharmacopoeia. The compound body of the Lichen is known as a thallus. Although subject to great variation of form all the kinds may be separated into two groups — those that lie flat and spread upon the surface they grow upon, and those that branch and grow in a vertical direction. The first kind are known as foliaceous Lichens, the second kind as fruticulose Lichens. The Dog Lichen is an example of the foliaceous class, the Reindeer Moss may stand as representative of the fruticulose class. There is a subdivision of 534 HUTCHINSON'S POPULAR BOTANY each? of these groups, for some of the foliaceous Lichens are of very hard texture, and to these the term crustaceous is applied. So. too, some fruticu- lose Lichens have their lobes or branches reduced to fine threads and are therefore denominated filamentous. The Beard Moss ( Usnea dasypoga, fig. 673) is of this kind. Neither Algse nor Fungi are long-lived plants, although the woody Fomes among the Fungi may subsist for twenty years or so ; but no such limit can be set to the life of some of the foliose Lichens. Any one who over a long period of years has made observations in any particular district must have noticed how certain patches of Lichens on old walls or rocks maintain their position with little apparent increase of size. The combination of the two elements in their structure appears to give them the power of almost per- petual renewal. Berkeley expressed his belief that " Patches of such Lichens as Lecidea geographica probably date from almost fabulous periods, and even small patches are often of considerable age. I have myself watched individuals for twenty-five years, which are now much in the same condition as they were when they first attracted my notice." The same belief must have been in Euskin's mind when he penned a much-quoted passage in " Modern Pain- ters," for one of its sen- tences runs : " The orange stain upon the edge of yonder western peak re- flects the sunsets of a thousand years." This durability of the living Lichen remains when specimens have been collected for reference by the student. This fact should make the group a favourite one with collectors, though it has not done so to any extent. Lichens require none of the troublesome preparation demanded by most natural history specimens. Exposure to the indoor atmosphere without pressing in porous paper will secure their satisfactory drying with little (in many cases no) loss of the living form, and even in those cases where there is shrinkage a few minutes' soaking in tepid water will restore the plumpness and pliability that may be necessary for purposes of study. It was formerly held that Lichens obtained their nourishment entirely from the atmosphere, but the modern view is that the rhizoid filaments of the Fungus partner draw water and mineral substances from the stratum upon which it grows, and this material, useless to the Fungus, the Alga can work up in the sunlit upper tissues into proteids upon which the Fungus FIG. 678. — BROWN MOULD (Mucor mucedo). (a-c) Gonidia from which the plant develops, (d) Sporange. (?) The same bursting to release the spores. 535 530 HUTCHINSON'S POPULAR BOTANY can feed. In return the waste products of the Fungus can be again utilized by the Alga. It will be seen that the partnership is not absolutely equitable, for whilst the Alga can live without assistance from the Fungus, the latter is entirely dependent upon the Alga. Where the Lichen grows upon the bark of trees or upon the soil, the Fungus partner may get most of what it requires from the humus, but in the case of species growing upon the vertical face of a rock there can be no question that the Fungus is Plw.u c,j,j [E. Step. FIG. 680. — THE SOLITARY TOADSTOOL (Amanita solitaria). A representative example of the Agarics, in which the spore-bearing surface is spread over radiating plates (gills) on the underside of the cap (pileus). The hanging frill or ring around the stem was, before the expansion of the Toidstool, spread over the gills and attached to the edge of the cap. entirely dependent upon the activity of its algal partner. Reproduction is of two kinds : both Fungus and Alga produce spores which set up new partnerships, and brood-buds or soredes separate from the thallus. These consist of one or more algal cells invested by a few wisps of the fungal hyphse. The methods of spore-bearing in the Fungi differ greatly, but the spores are mostly formed non-sexually by a cell dividing transversely, the dividing portion rounding and dropping off as a spore. In the moulds (Oomycetes, HIDDEN MARRIAGES 537 FIG. 681. — EARTH STAR (Geaster hygrometricus). The outer layers of the peridium have split and curled back, and the spores are escaping from the apical opening. Zygomycetes, etc.) they are formed singly or in chains, terminating branches. They may be formed by a division of the protoplasmic con- tents within a mother-cell, which thus becomes a sporange, the spores being liberated by the rupture or disappearance of the sporange-wall. These spores may be motile (zoo- spores) by the activity of cilia, as in Saprolegnia and Peronospora (fig. 676), or non-motile, as in Miicor (fig. 678) and the great majority of the Ascomycetes. These spores germinate under favourable conditions by pushing out germ-tubes which lengthen and branch until they form a new mycele. Moist and thin-walled spores that do not soon find the conditions favourable to germination perish ; but many dry spores, if kept dry, retain their vitality for very long periods, and some of these (resting-spores) will not germinate until after some definite period from the time they were formed. In some groups there is no sexual generation, or at least such has not yet been discovered. This is the case, among others, of the larger Fungi, the Basidiomycetes, which includes the Mushrooms. Where it occurs it chieiiy follows one of two methods. In Peronospora, Achlya, and possibly some Ure- dinese, an oosphere is fertilized by the intrusion of an antheridial tube from an antherid formed on the same or a neighbouring branch. In Zygomycetes two special cells come together by their apices and become firmly united. The apical portion of each (gamete] is then cut off by a transverse wall, and the division between the gametes gradually disappears, and the con- 6- „ % , tents of both conjugate, the united d e mass growing into a zygosperm. spatting into eight segments. Phgto ^ [£. Slep. . . FIG. 682. — EARTH STAR (Geaster hygrometncus). . , The two outer coats (combined) are shown m the act of 538 HUTCHINSON'S POPULAR BOTANY As indicated above, it is a common error to regard a mushroom or toadstool as the Fungus. We might as correctly regard an apple as the apple-tree by which the apple was produced. The apple is the fruit, which could not be formed without the preliminary activity of the vege- tative system — the roots, stem, and leaves. So with the toadstool, it appears only after a considerable amount of activity on the part of the vegetative body, in this case the mycele. If a toadstool be carefully taken up with the surrounding earth, dead leaves, or rotting wood from which it springs, it will be seen to be a t - tached to the matrix by a large num- ber of white or colourless threads of great fine- ness. This is the mycele or fungus proper, of which the toadstool is the carpo- phore or fruit-bearer. Usually these threads are s e p tat e — that is, they are broken up into com- partments by transverse walls ; or, to put it in another way, they consist of slender cylindrical cells placed end to end. The tip of one of these threads farthest away from the base of the toadstool is the growing point, and it appears to have special powers bej^ond that of increasing in length. When a tree breaks out into large brackets of Fomes or Polyporus, the owner sometimes thinks he will cure the disease by taking away the brackets, but these are rather symptoms than the disease itself, though they hold within their tubes the germs by which the disease may be spread. The tree is already doomed, for the deadly mycele has ramified through the trunk and branches, demoralizing the sound timber and con- Photo &#] [E. Step FIG. 683. — CRESTED CLAVAKIA (Clavaria cristata). An example of the branching species of Clavariese. A pure white or cream-coloured species found in damp woods. itiSSW 540 HUTCHINSON'S POPULAR BOTANY verting it into touchwood. The growing point of the mycele comes in contact with a wood-cell, and pours out a ferment which has the power to break down the hard wood into cellulose, which further dissolves into a fluid which the mycele can then absorb. The mycele of a toadstool that springs from a bed of dead leaves acts upon the cells of the leaves in the same manner. They crumble into humus, in which condition their material is again available for nourishing the roots of the green plants. Some forms of Fungi appear to exist only in the mycele stage, and are known as Mycorhiza. This Mycorhiza has been found to be a pretty constant attendant on cupuliferous trees — oak, beech, alder, hazel, etc. — in- vesting the rootlets as with a spider's web, and by breaking up the humus with its ferment reducing it to a condition which enables the rootlets to absorb it. It is the mycele again that is the destructive agent in "Dry Rot" (Merulius lachrymans), that in this country chiefly affects worked timber in houses, and spreads even through mortar so long as it has its base in the wood-work. The huge fan-shaped sporo- phores may be cleared away, and the house-owner fondly imagine that he has got rid of the pest, but the stout beams will continue to give way and the flooring to crumble like pasteboard. Nothing short of clearing out all the affected wood and the ramifying mycele and the pickling of new material in some known fungicide will put an end to the trouble. In some of the species that attack trees this mycele runs up between Photo by] [E. & FIG. 685. — JEW'S-KAR FUNGUS (Hirneola auricula-judce). Growing upon old Elder branches. It is an example of the Tremellinese. Several stages in the development of the sporophore are shown. Some specimens bear a remarkable likeness to a human ear. HIDDEN MARRIAGES 541 the bark and the wood, and ultimately attains to a flat, horny network, known as a Rhizomorph, such as we have already illustrated (fig. 181). Another form taken by the mycele of certain species of Fungus is known as a sclerotium. The best-known example of these sclerotia is afforded by Ergot (Claviceps), which grows upon Rye and other grasses, and is used as a medicine in special cases. The Ergot spores floating in the air, or carried by an insect, alight on the flowers of grasses, and there germi- nating, the mycele enters the ovary and feeds upon its contents. Instead of the ovule developing into a "grain" or seed, there emerges from the ovary a long, black, curved body, the sclerotium, which con- sists of hardened mycelium, and bears upon its surface conidia, or chains of spores. These sclerotia are shown in fig. 686 on the grass Molinia cterulea. When fully developed they fall to the ground, and remain quiescent through the win- ter ; but in spring slender little mushroom-like bodies grow out of them. AVithin the globose heads the spores are produced, which, escap- ing into the air, get into the flowers of grasses and renew the cycle. Other £ tT\ ' i Photo by] [E. Step. species ot i ungi also pro- ?• FIG. 686. — ERGOT (Claviceps microcephala). dUCe SClerOtia, but the ex- On the grass MoUnia ccerulea. The large curved bodies are the sclerotia ample given must suffice. which fal1 to the earth' and in sprin? give rise to the sporophores- The illustrations to this chapter will serve to give some idea of the striking differences of form in the sporophores of the various groups into which the Fungi have been divided. These are too numerous to be examined in detail here; we can only glance at a few of the different 542 HUTCHINSON'S POPULAR BOTANY types of sporophores. Such examples as we are able to mention and illustrate are sufficiently striking to those who imagine that Fungi are either toadstools or moulds. Between these two types there is a long line of forms differing widely from both extremes. The order Hymenomycetes is so called because the spore-bearing surface consists of a membrane (hym&nium), which is fully exposed when the sporophore is properly mature. It is divided into six families. The Solitary Toadstool (Amanita solitaries fig. 680) may be taken as Photo by} FIG. 687. — DRY ROT (Merulius lachrymans). Portions of the IIIIL'C sporophorp (several feet across) developed on oak panelling. The most destructive pest of worked timber. an example of the family Agaricinese, which is divided into several sections according to the colour of the spores — white-spored, pink-spored, yellow- spored, and black or purple-spored. In this family, consisting of the mushrooms and toadstools, the sporophore consists typically of a stem (mostly central) supporting a piieus or cap, whose lower surface bears a large number of plates (gills) set on edge and radiating from the stem. The object of this plan of structure appears to be to increase the spore- bearing surface, for the hymenium is spread over both sides of the *"* S- = I- 3 ill s 543 544 HUTCHINSON'S POPULAR BOTANY plates, and so has an area enormously greater than that of the pileus. This surface is closely packed with club-shaped processes, some of which are sterile and rounded at the summit. Others (basidia) end in four sharp points, each surmounted by a spore. When the sporophore first makes its appearance, owing to the elongation of the stem pushing it through the soil, it is more or less spherical and com- paratively small. In the case of the genus Aman- ita the entire sphoro- phore is invested by a general wrapper (volva), which is ruptured by the lengthening of the stem and the expansion of the cap, the latter breaking the upper portion of the volva into scaly frag- ments, which may be seen on the cap in the photograph. In some genera no remains of the volva are left on the cap. In Amanita the gills are further protected in the unexpanded toadstool by a delicate membrane (the veil) which spreads from the stem to the margin of the pileus, from which it separates and hangs as a beautiful frill around the upper part of the stem. In the Family Poly- porese the place of the gills is taken by a sponge-like mass consisting of tubes packed closely together, and the spores on their basidia are contained in the tubes. The tube-mass may be soft (Boletus), corky (Polyporus), leathery (Polystictus), woody (Fames), etc. The characteristic of the Hydnese is the substitution of spines for tubes or plates. In Thelephorese there are neither gills, tubes, nor spines, the basidia being FlG. . — Tremella mesenterica. This representative of the Tremellinese grows on dead branches, and is of a rich golden-yellow colour and the consistency of jelly. HIDDEN MARRIAGES 545 borne upon a smooth and fully exposed hymenial surface. A similar arrange- ment is found in Clavariese and Tremellinese, but in these there are considerable differences in the forms of the sporophore. Two photographic examples are given of the Clavariese — the Crested Clavaria (Clavaria cristata, fig. 683), and the Sparassis (Sparassis crispa, fig. 684), the latter a choice edible fungus found in pine-woods. Some of the genera of Hydneae and Thelephorese are represented by encrusting species that lie with the under or sterile surface FIG. 690. — Mitrula phalloides. A. wax-like Fungus of marshy ground, representative of the Discomycetes. IE. Step. closely attached to dead branches and twigs much after the manner of Lichens. One of the best known of Fungi — Stereum kirsutum, which forms small leathery brackets on old posts and stumps — belongs to the Thelephorese ; as also does one of our few luminous Fungi — Corticium cceruleum, which is bright deep-blue in colour, and gives out a pale greenish light in the dark. The sixth Family— Tremellinece — consists of more or less gelatinous Fungi of which two characteristic photographs are presented — the Jew's-ear (Hirneola auricula-judce, fig. 685) and Tremella mesentenca, fig. 689). The n—17 546 HUTCHINSON'S POPULAR BOTANY FIG. 691. — CT.USTER-CUPS. small portion of a cluster seen in section, showing the spores within. latter is so jelly-like in consistence that it is impossible to handle it in a fresh condition. It is frequent on dead branches, and is a beautiful rich golden yellow in tint. It has no stem and no definite shape, but is variously folded and twisted, often like a miniature turban of yellow silk. The Jew's-ear is a remarkable form that grows upon the stems and branches of dead and dying elders and, occasionally, on elm-stumps. Some specimens are remarkably like the human ear with its folds and lobes. It is of a gristly consistence with minutely velvety exterior, of a greyish-brown tint ; the interior polished and of a paler hue, and it is on this surface that the spores are produced. The Order GasteromycetesB includes the Puff-balls and Earth-stars. The characteristic of this order is the complete seclusion of the hymenium or spore- bearing surface in an enclosed sac until the spores are ripe and ready for dispersion. The Puff-balls (Lycoperdori) are familiar objects in summer and autumn. The "ball" is technically a peridium whose walls are com- posed of two layers, of which the outer breaks up into spines or warts which are clearly shown in fig. 679. In some species these fall away as the fungus becomes mature. The spores are produced in the interior and are liberated by the peridium opening at the summit. The Earth-stars (Geaster, figs. 681, 682) have the peridium com- posed of three layers which are at first entire, and constituting a depress e|d sphere : but as the spores ripen the two outer layers split into a variable number of segments and turn down. In the common species repre- sented (Geaster hy grometricus) ^e segments of the photo 6y] FIG. 692. — BIRD'S-NEST FUNGUS (Cyathus vernicosua). \E. step, Quaint little cups (peridia) containing spore-cases (peridiola) attached to the cups by long elastic threads. Representative of the Gasteromycetes. Photo by] FIG. 693. — CANDLE- SNTJFF FUNGUS (Xylaria hypoxylon). [E. Step. One of the Pyrenomycetes, that grows upon old stumps. The black, flattened, and branching conidiophores present much the appearance of wicks that have smouldered out. The whiteness is due to the tips being coated with the conidia. 547 548 HUTCHINSON'S POPULAR BOTANY when dry curve up over the endoperidium, but in moist weather bend back and lever the Fungus free from the soil. The remarkable Stink- horns are included in this order. The common species, Ithyphallu* impudicus, issues from the earth as a white ball. A little later the volva or wrapper is ruptured and a tall cylindrical column of white spongy substance issues from it. It is terminated above by the conical gleba, which consists of honeycomb-like cells at first filled with an olive jelly in which the spores are immersed, and which gives off an« abominable and pena- trating odour of corruption. This odour attracts innumerable blow-flies, and as the jelly is sweet they imbibe it greedily. The spores pass uninjured through their digestive tract, and are thus widely dispersed. The Order Ascomycetese is broken up into two large sub-orders — the Discomycetese and the Py- re nomycetese. The Discomy- cetes produce their spores in as ci or bladders im- mersed in the naked hyme- n i u m and opening on the surface when ripe. Many of them are disc- shaped (Pezi- zw, etc.), others have club- shaped or glo- bose heads. Of these latter the Morel (Morchella es- cuLenta, fig. 688) is a fa- miliar exam- ple. The hy- menium lines deep poly- gonal pits and is exposed Photo ly] [E. Step. FIG. 694. — HOKN OF PLENTY (Craterellus cornucopioides). A large black funnel-shaped fungus bearing spores on its ribbed outer surface. A representative of the Thelephorese. HIDDEN MABBIAGES 549 Photo by] [E. Step. FIG. 695. — FAIRY CLUBS (Clavaria argillacea). A wax-like greenish-yellow fungus, found rarely upon heaths. An example of the unbr of Clavarieae. :il (simple) species from the first (see also fig. 201 for a photograph of an example in a younger condition than those shown in fig. 688). The Pyrenomycetes include the Truffle (Tuber cestivum), which is wholly subterranean in habit, the Hart- truffles (Elaphomyces, fig. 196), Cordyceps (figs. 195, 196), the familiar Candle-snuff Fungus (Xylaria hypoxylon, fig. 693), and Ergot (Claviceps, fig. 686) already described. Little more than mere mention can be made of the remaining Orders. The Hysteriacese consists of Fungi which vegetate under the epidermis of plants and whose ascophores burst through and present the appearance of a black elongated low excrescence with a longitudinal slit. Some take -a stellate form, and others rise vertically in the shape of a miniature mussel- shell. They are all minute species. The Phycomycetese is a small Order of Mould-like Fungi whose mycele consists of unicellular threads, that is to say there are no transverse partitions breaking the thread up into cells or compartments. A familiar 560 HUTCHINSON'S POPULAR BOTANY example may be found in the white mould (Mucor mucedo) which appears upon jam, fruit, saccharine fluids and drugs. From the mycele rise hyphce of similar structure upon whose summit is formed a comparatively large spherical sporange whose thin membrane bursts to release the spores. The Potato 'Blight (Phytophthora infestans) and the Salmon Fungus (Saprolegnia ferox), an aquatic Fungus, also be- long to this Order. The Uredinese is an Order of plant parasites, and the fructification in some species takes the form of the well-known " clus- ter-cups" which burst through the tissues of living plants. In addition to cluster-cups (ceci- dia] there are sper- mogonia, uredo- spores, and teleuto- spores. In some species of Puccinia all these grades are passed on the same host. Such species are known as Auto- Puccinice ; but in others, known as Hete.ro -P ace inice, some stages are passed on one plant and the remainder upon a plant be- longing to a different genus. A familiar example of this Hetercecism, as it is termed, is afforded by the Mildew of wheat. The spermogonia and sscidia are found on the Barberry, and known as dScidium berberidis; the uredospores and teleutospores develop on Wheat, and are known as Puccinia graminis. The secidiospores from the Barberry will germinate on the Wheat and produce uredospores and teleutospores which germinate on Barberry. A similar case is illustrated by our photos (figs. 696, 697). The shoots of Photo 6y] [E- Step. FIG. 696. — HAWTHORN CLUSTER-CUPS (Rcestelia lacerata). A spindle-shaped mass of secidia which distorts branches of hawthorn, etc. A stage in the history of the Fungus shown on the opposite page. Photo by] \E. Step. FIG. 697. — Gymnosporangium clavaricBforme. The spore of Roestelia germinating on Juniper produces this distortion of the stem, from which proceed the jelly- like, tongue-shaped fructifications, bearing spores which germinate on hawthorn and produce the mass of Cluster- cups shown in fig. 696. 551 552 HUTCHINSON'S POPULAR BOTANY Hawthorn, Pear, and Whitebeam may often be found swollen and scurfy. The leaves and fruit are subject to the same diseased condition. Examina- tion with a lens will show that this spindle-shaped orange swelling consists of a crowd of cluster-cups. Formerly it was considered as a distinct species under the name of Rcestdia lacerata. Under the bark of Juniper in autumn there develop teleutospores of Gymnosporangium clavariceforme, and in the following April or May these burst through the bark as cylindri- cal or tongue-shaped masses of pale orange jelly. This stage is perennial on the Juni- per, and the spores are carried by the wind to the Hawthorn, etc., where they develop and give rise in the autumn to the cluster- cups of Rcestelia lace- rata, which is not per- ennial but only tem- porary. One other example of this heteroecism may be mentioned. The Silver Fir suffers from a fungoid disease known as Pine-shoot- twist (Geoma pinitor- quum\ and the Larch from Larch-leaf-rust (Ceoma laricis). On the leaves of Aspen may be found minute b r o w n i s h-y e 1 1 o w cushions known as Melampsora, tremula, Now these three plant diseases are all caused by one Fungus, whose teleutospores are produced on the Aspen-leaves and carried by the wind to both Silver Fir and Larch, where they produce other stages in the cycle. The Ustilaginese are similar to Uredinese in the fact that they are para- sites— entirely on herbaceous plants. The mycele is deep-seated in the tissues of their victims, running along the intercellular spaces and often thrusting FIG. 698.- — STONEWOBT (Chara fragilis). (a) Portion of the plant in fruit; (6) fertile leaf with spherical antheridia and spirally walled archegonia ; (c) antheridium ; (d) archegonium ; (e) spore; (/) antherozoid. HIDDEN MABRIAGES 553 FIG. 699. — Corallina officinalis. n Seaweed whose steins and branches are thickly coated with lime. (6) Tetraspores. produces its spores within the suckers through the cell-walls. This mycele is perennial — that is to say, where the host is a per- ennial plant. In each species there is some particular part of the plant where hyphse break through to pro- duce their spores on the surface. These spore-masses, usually black or some dark colour that looks black to the unassisted eye, have caused the pests to be known as " Smuts." Most people have seen a field of corn with the ears all " smutted," or covered with the spores of Ustilago segetum. Tilietia grains of Wheat, and causes the condition known to farmers as u bunt." Urocystis violce disfigures the leaves of Violets, and lives perennially in the rootstock. The Sphseropsidese are also minute Fungi. They produce perithecia like the Pyrenomycetes, but these have no asci, the sporules or stylospores being produced within the apex of hyphse. The Hyphomycetese include the well-known Mould Penicillium glau- cum, and a large number of plant- pests ; but many of them are sus- pected of being not real species, but temporary stages in the develop- ment of some of the larger Fungi. The Class CHARACE.^, or Stone- worts, consists of only two Orders, Characese and Nitellese. They are delicate fresh-water plants which have a superficial similarity of form to the Horsetails ; that is, there is a main stem with whorls of leaves, and branches of similar structure to the main stems. The leaves spring from distinct nodes, as in the Equisetacese, and the branches from the axils of some of the leaves, where also are found the sexual organs. The entire internode — i.e. ,-, -, , , FIG. 700. — A RED SEAWEED (Polysipnonw, the space between two nodes — subulata). Consists Of One Very large Cell, in (a) Tetragonidium in two stages of growth. 554 HUTCHINSON'S POPULAR BOTANY Chara invested by a cortex consisting of long slender cells arranged spir- ally, but in Nitella there is no such cortex, and the internodal cell stands absolutely naked. Chara also extracts calcium carbonate from the water, and deposits it on its exterior to such an extent that it is often difficult to make out the structure through it. Nitella has no such de- posit. Long tubular cells grow downwards and serve as roots to fix the plant in the soil. In the clear internodal cells of these plants may be observed the phenomenon known as cydosis, or rotation of the protoplasm along well-defined routes up one side of the cell and down the other, the two currents being separated by clear bands devoid of chlorophyll. In the axils of the leaves will be seen two kinds of bodies, some round and orange-red, the others elliptical and apparently green. The red bodies are antherids, the green are oogones. These oogones under the microscope are really orange, but the colour being masked by surrounding green bracteoles, they appear green to the naked eye. Some plants produce organs of one kind only; in others the two kinds are found close together. Each of these organs is supported on a short stalk consisting of the pedicel-cell (fig. 698). The walls of the antherid are composed of eight flat cells, and from the centre of each on the inner surface a cylindrical cell — the manu- brium — is attached, and extends towards the centre of the antherid, where it supports a rounded cell, the capitulum. Each capitulum in turn supports six secondary capitula of smaller size, and each of these bears four coiled fila- ments, which are divided into a large number of fiat cells, and in each of these is a spirally coiled antherozoid, like those of the Mosses, with a couple of long cilia at the anterior extremity. When these are ripe, the antherid falls apart and the antherozoids move through the water by lashing their cilia. The red colour is due to FIG. 701. — SUGAR TANGLE the inner face of the wall-cells being lined with (Laminarm saccharin*), chlorophyll-grains, which turn red as the antherid With root-like suckers holding to a , , piece of rock. develops. FIG. 702. — SAW-EDGED WRACK (Fucus serratus). One of the commonest of the larger olive seaweeds or wracks, found covering nearly all rocks between tide-marks. A valuable breakwater. 555 556 HUTCHINSON'S POPULAR BOTANY The walls of the oogone consist of long twisted cells, the whole sur- mounted by a crown of five or ten smaller cells, which ultimately separate and form a neck with a central cavity leading to the interior. Here there is a large central germ-cell (oosphere) with a receptive spot at its apex, which becomes liquefied and so allows entrance to the antherozoids when they have passed the narrow passage of the neck. After fertilization the outer coats of the oosperm harden into a black pericarp, and later the entire fruit falls off the plant to the bottom of the pond, where it remains inactive till the following spring, when germination takes place. At this period the oosperm has divided into one large and two small cells, the first apparently serving as a reserve of nutriment, whilst from one of the smaller cells a primary root is de- veloped, and from the other the proembryo — a long filament composed of a single row of cells. Across this a primary node is formed, from which arises a whorl of rhizoids, and beyond the node a very long inter- node ; then another node, from which arises a cluster of leaves, amid which a bud is formed, and from this the new plant takes its origin. The proem- bryo is continued to a great length beyond the second node. It will be seen that in the entire life-cycle of the Characese there is no sporophyte, so there is no true alternation of generations. We now reach the huge assemblage of forms that were until recently grouped together under the general name of Algse, but are now separated into a number of distinct Classes. Many of the species are familiar, as common Seaweeds and plants of fresh-water ponds and streams. As in the case of the Fungi, we can here only give a very brief indication of the characters of each class. The RHODOPHYCE.E, or Red Seaweeds, sometimes termed Floridese, get their name from the fact that in most of the species the chlorophyll in the cells is masked by a red pigment known as phyco-erythrin. They are Photo by] FIG. 703. — LIME-SECRETING PLANTS. \_E. Step The base of this group is a limpet whose shell has been thickly encrusted by the strong seaweed Lithothamnium, from which grows a plant of Corallina. HIDDEN MARRIAGES 557 attached by suckers to rocks, shells, or other weeds, but have no true roots, absorption being performed by the surface-cells of the entire thallus. This assumes a great variety of forms, from the mere threads of Batrachospermum and Cal- lithamnium, consisting of a single row of cells, to the broad leaf-like ribbons of Delesseria with midrib and nervures mimicking the leaves of Phanerogams. In Corallina (figs. 699, 703) the thallus is so completely in- vested with a layer of cal- cium carbonate that its vegetable nature is dis- guised, and the plants were long regarded as true corals. There is no alternation of generations, but there are two modes of reproduction — sexual and asexual. The asexual mode is by the division of a mother-cell or sporange, usually into four (hence distinguishable by the name of tetraspores), which are set free by the rupture of the sporange walls. These tetraspores are not ciliated, and have no power of motion, but float with the bea currents until they come to rest and vegetate on some suitable surface. The sexual organs are antherids and carpo- gones. The contents of the antherid, instead of being broken up into anthero- zoids, go to form a more or less spherical spermatium. The carpogone has a basal flask-shaped portion surmounted by a filamentous extension, the FIG. 704. — Jania rubens. The fine thread-like stems grow in clusters from the stems of other Sea- weeds, as here shown. The threads are all coated with lime. 558 HUTCHINSON'S POPULAR BOTANY trichogyne. The basal portion contains the oosperm, and the trichogyne serves as a receptive organ for the spermatium. As the spermatia drift helplessly through the water, one or more become attached to the trichogyne, their contents pass through the walls of both organs and reach the oosperm. By a complicated process, varying in different species, there arise a number of carpospores, which are enclosed in a general envelope, the whole body being known as a cystocarp. Ultimately the walls of this are ruptured, and the carpospores thus set free give rise each to a protoneme, from which a thallus is developed. Several other species in allied genera develop similar coatings of calcium carbonate, and like Coral- Una were formerly regarded as of animal nature. One of these, Jania rubens, is shown in fig. 704 growing in tufts on the stems of another Seaweed. Lithothamnium encrusts the walls of rock-pools, and forms strong masses on limpet-shells, often whilst the limpet is still oc- cupying the shell. Such an ex- ample is shown in fig. 703 with a small plant of Corallina growing upon it. When this specimen fell into our hands it presented no re- semblance to a limpet, though it was gliding over the rock. Hali- meda tuna, a large green species, presents much the appearance on a small scale of the Prickly Pear Cactus (Opuntia\ its points being broad at the top and narrowed to the base. Like Corallina and Lithotkamniwm, it secretes calcium carbonate to such an extent that its dead remains form beds of limestone of considerable thickness in which the forms of the joints are well preserved. The well-known Carrageen (Chondrus crispus) is a member of the Rhodophycese. At one time it was a fashionable food for invalids under the name of Irish Moss, the prevailing fad of the medical profession of that day being that anything glutinous was nourishing. Laver (Porphyra laciniata} has also had — and still has — its advocates as a food, or at least as a sauce, when pounded and stewed, or pickled in salt. Murlins (Alaria esculenta] and FIG. 705. — Polysiphonia. Portion of female plant with vorticella (d) ; (a) trichogyne (6) forked hair; (c) sporogone. FIG. 706. — ASH-LEAVED SEAWEED (Delesseria sanguinea). One of the most beautiful of the Seaweeds, mainly by reason of its colour. Its fronds are clear rosy-red, and so thin as to be almost transparent. The figure is a little less than natural size. 559 560 HUTCHINSON'S POPULAR BOTANY other seaweeds have also been used as food, chiefly by the maritime peasantry and fisher-folk. Speaking of the fertilization of Polysiphonia subulata, which belongs to this class, Professor McAlpine says : " It is evident that the element of chance enters largely into the meeting of the passive male and female elements, and it is not to be wondered at that in many cases fertilization never takes place at all. Professor Dodel-Port has, however, recently observed that Infusoria create currents in the water and thus set the passive sperm-cells [spermatia] in motion. Numerous Vorticellae, or Bell-animal- cules, attach themselves to this seaweed, and create currents which send the sperm-cells spinning about, while the forked hairs beside the trichogyne help to break the force of the current and cause the sperm-cells to settle there. Just as insects obtain pollen or honey from a flower while un- conscious agents in its fertilization, so do these water-animals swallow some of the sperm-cells for their pains. Contrivances in Flowerless Plants for ensuring fertilization may not be less wonderful, when better known, than those brought to light in Flowering Plants " (fig. 705). The PH^EOPHYCE^, or Brown and Olive Sea- weeds, include the Wracks and Tangs, which are abun- dant and conspicuous on the rocky coasts of the colder seas (figs. 701, 702, 714). Here, again, there is great diversity of form, size, and structure, which may be well exemplified by a comparison of the thread- like rows of simple cells in Ectocarpus with the broad leathery fronds of Lami- naria and Alaria on our own coasts, the Antarctic Macrocystis, with floating ribbons two or three hun- dred yards long, and the tree-like Lessonia of the same regions. Reproduc- tion of the Brown Algae varies in the several orders. Photo™ [E-step- There are asexual swarm- FIG. 707. — PEACOCK s- TAIL (Padina pavorna). . . , spores produced in large A much-prized Seaweed of sandy shores. The light zones bear . lime crystals. numbers and discharged HIDDEN MARRIAGES 561 Photo by} A. handsome Red Seav FIG. 708. — Halymenia Ugulata. The lobes of the variously divided fronds bear many shoots or branches. [E. Step. from lateral sporangia. There are bodies known as gametes formed in gametangia, which resemble the asexual swarm-spores, but which join in pairs, and, as a result of their fusion, give rise to zygotes, from which new plants develop. There are flask-shaped depressions (conceptacles) in the surface of the thallus, within which are produced antherids and oogones, the former discharging motile spermatozoids, and the latter oospheres. In most species the conceptacle is male or female ; in Fucus platycarpus both antherids and oogones are produced in the same conceptacle. Several species of Fucus are the most abundant seaweeds on our coasts, par- ticularly where there are rocks. Fucus serratus (fig. 702), and Fucus vesiculosus drape all the reefs and afford valuable cover for innumerable marine animals. The CHLOROPHYCE^E, or Green Algae, are of much simpler structure than the foregoing ; many of them consist of a single cell, and some of these, owing to their active motile powers, were formerly considered as low forms of animal life. The methods of reproduction are varied, and sexual union is not general. In the Order Protococcoidese all the species are unicellular, though in some there is a loose union of a few or many individuals into a colony that may give them the appearance of being multicellular. Some of these are found in all stagnant water and on wet walls and tree-trunks, multiplying by simple division of the cell, or by the breaking up of the protoplasm into a number of swarm-spores, each provided with a couple of cilia. These are set free by the rupture of the cell-wall. The Algae already n—18 562 HUTCHINSON'S POPULAR BOTANY FIG. 709. — BLADDER WRACK. Antheridia. Antherozoids are seen escaping from a separat antheridium. referred to as forming one of the elements in the composition of Lichens belong to this order. More strangely still, some of them (Zoo- chlordla) are found living in the cells of low forms of animal life, such as the Hydra, the Fresh-water Sponge, certain Planarian worms, and Infusoria, for whom they manu- facture starch, which animals are incapable of doing. Another method of reproduction found in this order is by the union of two naked motile masses of protoplasm, known as planogametes, which be- come fused together and form a zygote, which develops into a cell-family enclosed in a common envelope. The well-known Volvox, so long bandied about from zoologist to botanist and vice versa, is by some considered to be a hollow colony of single-celled Protococcids, each with its pair of cilia pro- jecting through the common envelope, whose movements give that revolving motion to the colony that has delighted all who have viewed it through the microscope. Within the colony smaller daughter-colonies may be seen revolving; also aggregations of ciliated spermatozoids. Large colonies may contain as many as twenty-two thousand individuals, each connected to five or six neighbouring cells by delicate threads of protoplasm. Certain of these cells develop into large egg-cells, which are fertilized by the spermatozoids. These egg-cells may be distinguished from the daughter- colonies by the lack of motion. When the egg-cells are mature, the old colony breaks up into its con- stituent cells, and the egg-cell (now an oospore) sinks to the bottom, and in a resting condition develops into a new colony. In the Order Confervoidese the individuals are multicellular, but in most cases the cells are in a single row, placed end to end, and form long fine threads. Some are fresh-water species, some marine, whilst one — Trentepohlia — is aerial. They are reproduced asexually by the pro- toplasm of certain cells breaking up into swarm-spores. There are two forms of sexual reproduction. FIG. ER WRACK. FIG 711. — FORKED SEAWEED (Furcellaria fastigiata). A very common Red Seaweed. The frond is reduced to round forking threads. The spores are produced ir pod-like receptacles at the tips of the forks. 563 564 HUTCHINSON'S POPULAR BOTANY Fia. 712. — BLADDER WRACK. Oosphere being fertilized by anthe One is by the fusion of two planogametes, as in Protococcoidese ; the other is by the enlargement of one cell into an oogonium containing a single cell, which is fertilized by a spermatozoid formed in another cell of the same or another filament. The Class CONJUGATE consists of fresh-water Algse very similar in appearance to the single- celled and filamentous forms of CHLOROPHYCE.E, but reproduction is effected asexually by simple cell-division, and sexually by the conjugation of two apparently similar cells resulting in the forma- tion of a zygosperm. The most familiar representatives of the class are the Yoke-threads (Zygnema, Spirogyra) and the Desmids, the former consisting of long green hair-like filaments growing in fresh-water, and the Desmids single-celled microscopic water-plants. Zygnema consists of a single row of transparent cylindri- cal cells, joined end to end, and ornamented within by spiral bands of endochrome which gives it a beautiful appearance under the microscope. They float loosely in or on the water and have no attachment suckers. Single cells broken off the thread have the power by cell-division to grow into long filaments, that is, complete plants. When two filaments come together so that their cell-walls are nearly in contact, conjugation takes place. A protuberance grows out from each of the opposite cells, and these shoots meet halfway between the threads, the cell-walls of the tips open to form a connecting tube between the two plants, and the contents of one cell pass into its neighbour, where they coalesce with the contents of that cell. There is complete union of this mass of protoplasm, which then rounds off into a sphere or an ellipse. It has become a zygosperm. In some species the union of protoplasm takes place in the connect- ing tube; in others no tube is formed, but the two plants come in contact by a knee-like bend in each which brings two cells in touch with each other, then the cell-walls between them disappear and a zygosperm is formed in one cell by the union of the contents of both. Occasion- ally two cells on the same plant will form a zygosperm by each sending out a tube which meets with the other and effects a combination of the two protoplasm masses. However formed, these zygosperm s ger- minate and give rise directly to a fila- Fio. 713. — BLADDER WRACK. Oogonium distended by its eight oospheres, and ready to split and release them. HIDDEN MARRIAGES 565 merit like those by which they were produced. Zygnema is common in both running and stagnant water, and forms the green slimy masses frequently seen floating on the surface of ponds and ditches. The Desmids are almost exclusively inhabitants of fresh water, and are unicellular. They are quite unattached — except temporarily resting, as it were — and float freely, having the power of spontaneous motion. Cer- tain species may combine to form threads, but the segments of such threads are separate organisms. They are all very minute, only the very largest of them — such as Cosmarium and Micrasterias — being just visible to the unassisted eye. They vary greatly in form, but all the members of a genus conform roughly to one type. They are all symmetrical, and each individual is usually divided into two sym- metrical portions by a constriction extending from the margin nearly halfway to the centre. Even the cell contents — chlorophyll bodies and starch-grains — are symmetric- ally grouped in bands and star- patterns. The transparency of the cell-wall enables these patterns and the rotation of the protoplasm to be seen clearly and distinctly. Some of the long slender species like Closterium and Docidium have clear spaces at their extremities in which " brownian movements " of the particles suspended in the cell- sap may be seen. In the large Family DIATO- MACE.E all the species are micro- scopic and abound in water, both fresh and salt. Thej^ are all single- celled plants whose cell-wall with few exceptions is highly silicified and takes the form of a slightly unequal pair of valves, each with a rim (girdle), the larger valve overlapping the smaller. The valves are transparent, and enveloped in an outer layer of thin gelatine. These valves are favourite objects with microscopists, who, however, rarely take interest in them as FIQ. 714. — BLADDER WHACK (Fitcus vesiculosun). Fertile branches bearing conceptacles (con.). 566 HUTCHINSON'S POPULAR BOTANY living plants, but take care to clean out all the protoplasm that they may quarrel about the perforations and sculpturing of the valves, which appear to vary according to the lens used for their definition. They are isolated and free-swimming, or variously attached to each other or to higher plants by gelatinous stalks. "Tripoli" and ': Kieselguhr " are deposits of the fossil Diatoms of past epochs, which occur in beds of considerable thickness in various parts of the world. The number of species of Diatoms known is enormous — certainly more than ten thousand ! In certain species of Diatoms conjugation is effected by two indi- viduals coming together, and after throwing off their siliceous valves the protoplasts become fused to form a new individual, which after- wards multiplies by division. But in the majority of Diatoms there is nothing ap- proaching a sexual union, and the purely vegetative multiplication by division appears to be the rule in the Classes PERIDINE^ and SCHIZOPHYTA. A few words should be said respecting the Class Schizomycetes or Splitting Fungi, better known as Bacteria, though they are so minute that they cannot be studied, or even seen, except by the aid of very high powers of the microscope. In consequence there has been much confusion as to form, structure, and development. They are single cells of spheri- cal, spiral, or cylindrical form, or combined to form chains and filaments. The cell-contents is homogenous protoplasm, in a few cases tinged with chlorophyll. Some have the power of free movement and of rotation round the longitudinal axis ; certain of these are possessed of cilia or flagella, but whether these are their organs of motion has not been made out satisfactorily. The spherical forms are known as Coccus or Micrococcus, the cylindrical as Bacillus and Bacterium according to whether the}' are relatively long or short, and the spiral forms as Spirillum. Coiled forms other than spirals are known as Vibrio, and the compound • fila- ments as Leptothrix and Beggiatoa. They are reproduced by the cell- contents developing into spores, which are set free by the rupture of the cell-wall, or in the filamentous species by the breaking off of cells Fia. 715. — YOKE-THREAD (Zygnema). Two threads in proximity have united by tubes through which the cell-contents mingle to form zygosperms. FlG 716. — THE CBIMSON PLUME (Ptilota plumosa). autiful example of the Red Seaweeds. Its usual plm-e of growth is on the long stem of th great Oarweed (Laminaria digitata). 567 568 HUTCHINSON'S POPULAR BOTANY which develop into filaments again by cell-division. The hardiness of most species is astonishing : they stand extremes of heat and cold, may be desiccated and remain alive for years, and some even retain their vitality in alcohol. Like the Fungi, they include both saprophytes and parasites. The saprophytes work chiefly by causing decomposition and fermentation ;' the parasites affect living animals, rarely living plants. As they are at least the accompaniment of many diseases in the human body, attempts have been made in some quarters to regard them as the specific cause of most diseases. Whilst there is no doubt that their malignant agency has been established in some of these (e.g. Bacillus anthracis in splenic fever, and the Comma Bacillus in Asiatic cholera), it must not be supposed that all Bacteria are to be looked upon with dread as human enemies. Many of them are known to be beneficent towards humanity, and others science has learned to educate, as it were, to service in the arts and manufactures. Respecting the MYXOMYCETES, or MYCETOZOA as they are variously called, there is still an amount of disputation as to their true position. By some they are re- garded as a group of fungi, and known as Slime Fungi, the ref or e proper to be included in a work on Botany ; but others con- ten d for their animal nature. Pro- duced from microscopic spores, they emerge as a kind of Am- oaba (swarm- cells) that glide with a, streamin g movementr t h rusting FIG. 717. — Mucilago spongiosa. [E. Step. One of the Myxomycetes that may be found in pastures climbing up the stems of grasses and weeds to form its sethalia. HIDDEN MARRIAGES 569 Photo by] Fio. 718. — Trichia varia. Common on decaying wood. The densely packed sporangia of ochreous tint are she IE. Step. slightly enlarged. out a whip-like process on the advancing side, surrounding Bacteria and other minute organisms and feeding upon them, chiefly in decaying wood and other vegetable matter. At a certain period of their life many of these come together and unite into a plasmodium, a creamy mass of naked protoplasm, which afterwards divides and forms sporangia, enclosing numerous dust-like spores like those by which the swarm-cells were originally produced. These sporangia differ greatly in form and size, each genus having its characteristic form and the species differing from each other in minor points, some becoming combined in cake-like or cushion- like masses of relatively large size, others forming small spherical or cylindrical bodies, stalked or sessile. Each swarm-cell possesses a single nucleus and a contractile vacuole. From the rear end it puts out finger-like processes (pseudopodia) with which it catches its food. The pseudopodia draw it into the body, where it is digested in the vacuoles. The swarm-cells increase in numbers by each dividing into two, and these dividing in the same manner again and again. When they unite into the creamy mass known as the plasmodium, they alternately advance and recede as a whole, but the movement is always more in one direction than the other. After a few hours the plasmodium 570 HIDDEN MARRIAGES 571 breaks up into few or many (according to species) smaller masses which form into sporangia. A crust forms around the sporangium and the enclosed portion breaks up into spores ; but prior to this a system of delicate threads is constructed, forming a network in which the spores are held. This is known as the capillitium. There are also in some species free threads called elaters, spirally twisted and hygroscopic. As the sporangium ripens and dries, the investing membrane breaks up by shrinking and the spores are only held together by the capillitium network. The elaters expand and contract, their movements throwing the spores out through the meshes of the capillitium. Many of them have granules of calcium carbonate in the walls of the sporangia and as knots on the capillitium threads. The same substance appears in the plasmodium. The period of nutrition corresponds with the amoeboid state — that is, the swarm-cell and the plasmodium. As swarm-cells they are negatively helio- tropic — they avoid the light and retire into the darkness of rotten wood and decaying leaves; ^1^ ^^*- but in the plasmo- dium stage their heliotropism be- comes positive — they stream out to- wards the light in order to form their FIG. 720. — DEVELOPMENT OF A MYXOMYCETE. sjnorancrifl OTI thf" The upper row shows : 1, a spore ; 2, the contents of the same emerging as a swarm-cell bpOIctllgld UU ^^ a nueleus . 3) the game with nucleuSi vacuoie, and flagellum ; 4, the swarm-cell P Y t P r i O r of their has assumed the amoeba form. Below is a portion of plasmodium, and to the right a sporange. All diagrammatic. habitat. The swarm-cells are also positively hydrotropic — they move from dry to moist places; and both swarm-cells and plasmodium are trophotropic — they move towards nutrient substances. De Bary, to whose researches much of our knowledge of the Class is due, decided in favour of their animal nature on account of the formation of a plasmodium by the aggregation of the swarm-cells. But although he said their place was " outside the limits of the vegetable kingdom," he continued to include them in his botanical works. What has always appeared to us a strong argument against their being driven out of the vegetable kingdom is that their exhibition of animal traits is restricted to their earlier stages of development. The test of their real nature should be applied to their ultimate condition and their mode of reproduction, both of which are essentially vegetable. The catching and digesting of Bacteria is indicative of animal nature, it is true, but what about the trapping and digesting of animal food by the Sundews, the Butterworts, Bladderworts, 1 572 HUTCHINSON'S POPULAR BOTANY and Pitcher-plants ? The power of movement in the swarm-cells is paralleled by similar movements in the antherozoids of many cryptogams : and the development of cellulose is by no means a common feature among animals. But however one may regard these Mycetozoa or Myxogastres, they remain an exceedingly interesting group, such as may be studied easily by all who walk in the woods and country lanes, and we shall try by a few examples of different types to give some elementary idea of their beauty and diversity of form and colour, such as may be acquired by a pocket lens— though for their serious and exact study the microscope is required to be brought into use, as the determination is largely based upon the character of the capillitium, the size and colour of the spores, and so forth. One of the largest of known species is Brefeldia maxima, of which we have already (fig. 186; given a photograph showing it in the plasmodium stage. The appearance of this plasmodium to one who only knows the "Myxies" as almost microscopic forms is astonishing. We have seen it issuing from a large pine stump, flowing out over the bark and climbing up the stems of plants at a short distance in sheets that would cover several square feet. There were no visible cavities in the stump — to all appearance the wood was sound. But they issued as microscopic swarm-spores from microscopic cavities, and multiplied by division on the exterior. A small portion of such an outflow is shown in the photograph of the natural size (see p. 149). After a time the creamy whiteness gets a pinkish tinge, then brown, and a crust forms over detached oval portions two or three inches long. The crust is somewhat shiny, of a dark brown colour, and with an indistinct tesselated appearance. This is an sethalium or compound sporangium, and the tesselated appearance is due to the fact that there are a large number of sporangia packed closely side by side. The semi- fluid creamy mass inside becomes a dry, fine powder like soot. The crust contracts, splits and flakes off, leaving the spores (for such is the powder i free to be blown out by the air-currents (fig. 719). Mucilago spongiosa. shown in fig. 717, also forms an sethalium, but it is quite different in appearance from that of Brefeldia, the sporangia com- posing it being more loosely compacted. Its creamy plasmodium may be seen in autumn creeping up the stems of grasses and weeds in pastures. At some distance up the stalks it consolidates into masses such as are shown in the photograph, which are thickly covered on the exterior with crystals of lime. Its spiny spores are dull purple in colour. Leocarpus fragilis may frequently be found on pine stumps, with large, polished, brown sporangia, clustered owing to the weakness and shortness of their stalks. Our photo (fi.g. 721) represents it in the plasmodium stage creeping among moss and pine-needles on a pine stump. The capillitium of some species expands to a remarkable size when the HIDDEN MARRIAGES 573 sporangia dehisces. This is particularly the case with several species of Arcyria. In Arcyria nutans, for an extreme example, the capillitium extends to about ten times the length of the sporangia from which it escaped. Trichia botrytis in the swarm-cell stage lives in wood that is thoroughly rotten and sodden, coming to the exterior to form a purple- brown plasmodium, and finally the massive-stalked pear-shaped sporangia. These are at first of a beautiful red colour ; but as they dry and harden FIG. 721. — Leocarpus fragilis. The plasmodium of this Myxomycete creeping over mosses and pine-needles on a pine stump. there is some reduction in the thickness of the stalks and the sporangia turn to yellowish-olive, red-brown, or purple-black. In some cases each sporangium stands apart on its own stalk, but in others from three to eight stalks will unite and support a cluster of as many sporangia. GLOSSARY OF TERMS [JVo/e-As the applicati been fully explained in the text, the repetition of the same here has been considered unnecessary.] Achene ; Gr. a, not, and cha ino, 1 open Acicular ; Lat. acicula, a small needle Actinomorphic ; Gr. aktis, a ray, and morphe, a shape ^Estivation ; Lat. (estas, summer yEthalium ; Gr. aithalox, soot Aleurone ; Gr. alenron, ground wheat Allogamy ; Gr. allo», other, and gamos, marriage Amentum ; Lat. a thong Amplexicaul ; Lat. amplcxus, embracing, and caulis, stem Anatropous ; Gr. anatrepo, to turn in or over Androecium ; Gr. andros, a male, and oikos, a house Anemophilse ; Gr. anemos, the wind, and phileo, to love Angiosperm ; Gr. aggeion, a vessel, and sperma, seed Annular ; Lat. annulus, a ring Annulated ; Lat. annutatus, ringed Annulus ; Lat. a ring Antherid ; Gr. antlteros, flowery, and id ion, a diminu- tive suffix Antherozoid ; Gr. antheros, and zoon, an animal Anthers ; Gr. antheros. Anthocyanin ; Gr. anthos, flower, and kuaneos, dark blue Antipodal ; Gr. anti, opposite, and pous, foot Apocarpous ; Gr. apo, separate, and karpos, fruit Apogamy ; Gr. apo, and gamos, marriage Archegone ; Gr. arche, a beginning, and yone, birth, production Archespore ; Gr. arche, and sporos, seed Aseidiform ; Gr. askidion, a little bottle Auriculate ; Lat. auricula, an ear Autogamy ; Gr. auto?, self, and gamos, marriage Bract, Bracteate; Lat. bractea, a thin plate of metal Caducous ; Lat. cndo, I fall Calceolate ; Lat. calceolus, a slipper Calypter ; Gr. calyptra, a covering or veil Calyx ; Lat. calix, a cup Cambium ; Lat. cambio, I exchange Campanulate ; Ital. campana, a bell Campylptropous ; Gr. campulus, curved Capillitium ; Lat. capillus, a bush of hair, or beard Capitulum ; Lat. a little head Carpel ; Gr. karpos, fruit Carposperm ; Gr. karpos, and sperma, seed Caryophyllaceous ; Gr. karuophullon, the clove-tree Caryopsis ; Gr. karuon, a nut, and opsis, appearance Cauline ; Lat. caulis, a stem Chlorophyll; Gr. chloros, green, and phullon, a leaf Circiiiate ; Lat. circiruitus, rounded Cladode ; Gr. klados, a branch Cleistogamic ; Gr. kleistos, closed, and gamos, marriage Coleorhiza ; Gr. koleos, a sheath, and rhiza, root Collenchyma ; Gr. kolla, glue, and enchuma, some- thing poured in Columel ; Lat. coluuiella, a little column Conduplicate ; Lat. conduplicatus, doubled Connate ; Lat. con, together, and natus, born Convolute ; Lat. combining, rolled up Cordate ; Lat. cor, the heart Corm ; Gr. kormos, a stem or trunk Cormophyte ; Gr. kormos, and phuton, a plant Corolla ; Lat. diminutive of corona, a crown Cotyledon ; Gr. kotuledon, a cup-shaped cavity Cremocarp ; Gr. kremannumi, to hang, and karpos, fruit Crenate ; Lat. crena, a notch Cruciform ; Lat. crux, & cross, and forma, form Cryptogam ; Gr. kruptos, hidden, and gamos, marriage Cucullate : Lat. cucullus, a hood or cowl Cuneate ; Lat. cuneus, a wedge Cyanic ; Gr. kiutneos, dark blue Cyanophyll ; Gr. kuaneos, and phullon, leaf Cystoliths ; Gr. kustis, a bag or bladder, and lithos, a stone Deciduous ; der.idcre, to fall Decurrent ; Lat. de, down, and curro, to run Decussate; Lat. dccitsso, to divide crosswise Dehisce ; Lat. dehiscere, to gape Dentate ; Lat. dens, a tooth Dichogamy ; Gr. dicha, in two parts, and gamos, marriage I 'ichotomous ; Gr. dicha, and tome, to cut Digitato ; Lat. digitus, a finger Dioecious ; Gr. di, two, and oikox, a house Distichous ; Gr di, and stichos, a row Elater ; Gr. an impeller Emarginate ; Lat. e, privative, and margo, a margin Endocarp ; Gr. endon, within, and karpos, fruit Endosmose ; Gr. endon, and dsmos, impulsion Endosperm ; Gr. endon, and sperma, seed Endospore ; Gr. endon, and sporos, seed Entomophilae ; Gr. entoma, insects, and phileo, to love Kpicarp ; Gr. cpi, upon, and karpos, fruit Epidermis ; Gr. cpi, and derma, skin Epiphyllous ; Gr. epi, and phullon, a leaf Epispore ; Gr. epi, and sporos, seed Exosmose ; Gr. cxo, outside, and dsmos, im- pulsion 574 GLOSSARY OF TERMS 575 Exospore ; Gr. exo, and sporos, seed Extrorse ; Lat. e.ctrorxum, outwards Fascicular ; Lat. fasciculus, a small bundle Filament ; Lat. Jilum, a thread Filiform ; Lat. Jilum, and forma, form Fistular ; Lat. listula, a pipe Flagellum ; Lat flagella, a little whip Fusiform ; Lat. fusus, a spindle, and for mi, form Galeate ; Lat. galea, a helmet Gamete ; Gr. wife or husband Gamopetalous ; Gr. yamos, marriage, and petal. Applied to corolla. Gamosepalous ; Gr. gamos, and sepal. Applied to calyx Gibbous ; Lat. gibiosus, humped Glume ; Lat. yluma, a husk Gluten ; Lat. paste Gynmosperm ; Gr. gumnos, naked, and sperma, seed Gymnostomous ; Gr. gumnos, and stoma, a mouth GyncBcium ; Gr, gune, a female, and oiko*, a house Gynandrous ; Gr. gune, and andros, a male Hastate ; Lat. hasta, a spear Heterophyllous ; Gr. hcteros, different, and phullon, a leaf Heterostylism ; Gr. heteros, and style Hilum ; Lat. a very small thing Hydrophilae ; Gr. udor, water, and phileo, to love Hypocrateriform ; Gr. hypo, under, and krater, a goblet Indusium ; Lat. an under-garment Inflorescence ; a collective name for all the flowers produced on one floral shoot Infundibuliforrn ; Lat. infundibulum, a funnel Introrse ; Lat. introrsum, inwards Involucre ; Lat. involucrum, a wrapper Involute ; Lat. involutus, wrapped up Labiate ; Lat. labium, a lip Laciniated ; Lat. lacinia, a fringe or border Latex ; Lat. juice Leguinin ; Lat. pulse Leukoplasts ; Gr. leukos, white, and plasma, that which has teen formed Loculicidal ; Lat. loculus, a little place, and ccedo, to cut. Malacophilse ; Gr. -nmlakoat, soft [mollusc], and phileo, to love Manubrium ; Lat. a handle Medullary ; Lat. medulla, the marrow Megaspore ; Gr. mega, great, and sporos, seed Meristem ; Gr. mcristos, divided Mesocarp ; Gr. mesos, middle, and karpos, fruit Metabolism ; Gr. metabole, a changing Micropyle ; Gr. mikros, little, and pule, a gate Microspore ; Gr. mikros, and sporos, seed Monadelphous ; Gr. monos, sole, and adelphos, brother Moniliform ; Lat. monila, a necklace Monoecious ; Gr. monos, one, and oikos, a house Mucronate ; Lat. mucro, a sharp point Multicellular ; made up of many cells Mycele ; Gr. mukos, mushroom, and kele, a tumour Napiform ; Lat. napus, a turnip, and forma, form Nodulose ; Lat. nodus, a knot Xucellus ; Lat. nucula, a small nut Nucleus ; Lat. nux, a nut or kernel Obcordate ; Lat. ol, inversely, and cor, the heart Obovate ; Lat. ob, and oratus, egg-shaped Oophyte ; Gr. oon, an egg, and phuton, a plant Oosperm ; Gr. oon, and spcrma, seed Oosphere ; Gr. oon, and sphaira, a sphere Orbicular ; Lat. orbiculus, a small disc Ornithophilse ; Gr. ornithos, a bird, and phileo, to love Orthotropoua ; Gr. orthos, straight Ostiolum ; Lat. diminutive of ostium, a door Ovary, Ovule ; Lat. ovum, an egg Pales ; Lat. palea, chaff Palmate ; Lat. palma, the palm of. the hand Panicle ; Lat. paniculu, cat's-tail Papilionaceous ; Lat. papilio, a butterfly Pappus ; Gr. pappos, the down of plants Paraphyse ; Gr. paraphus, growing beside Parenchyma ; Gr. parenchuma, the spongy sub- stance of the lungs Paripinnate ; Lat. par, equal, and pinnatus, leathered Pedate ; Lat. pedatus, from pcs, foot Pedicel, pedicillate, peduncle; Lat. diminutives of pes, pedis, the foot Peloria ; Gr. peloron, a monster Peltate ; Lat. pelta, a shield Perfoliate ; Lat. per, through, and folium, a leaf Perianth ; Gr. peri, about, and anthos, a flower Pericarp ; Gr. peri, and karpos, fruit Perichsete ; Gr. peri, and chaite, flowing hair Peridium ; Gr. peri, and idea, form Perigone ; Gr. peri, and gone, womb Perisperm ; Gr. peri, and sperma, seed Peristome ; Gr. peri, and stoma, a mouth Personate ; Lat. personatus, masked Petal ; Fr. petale, a leaf, used in reference to floral leaves only Phanerogam ; Gr. phaneros, evident, and gamos, marriage Phloem ; Gr. phloios, inner bark Phyco-erythrin ; Gr. phitkos, sea-weed, and eri/thros, red Phylloclades ; Gr. phullon, a leaf, and klados, a branch Phyllode ; Gr. phullon, and eidos, likeness Phyllotaxy ; Gr. phullon, and taxis, order Phylloxarithin ; Gr. phullon, and xnnthos, yellow Pileorhiza ; Gr. pileus, a cap, and rhiza, root Pileus ; Gr. a cap or helmet Pinnatifid ; Lat. pinnatus, feathered, and Undo, I split Pinnatisect ; Lat. pinnatus, and seco, I cut Pistil ; L&t. pistillum, a pestle Plasmodium ; Gr. plasma, anything moulded Plicate ; Lat. plica, a fold Plumule ; Lat. pluma, a feather Pollen ; Lat. fine flour or dust Polyadelphous ; Gr. polus, many, and adelphos, brothe s Primine ; Lat. primus, first Procarp ; Gr. protos, first, and karpos, fruit Prosenchyma ; Gr. pros, beside, and enchuma, something poured in Proteus ; a fabulous person who could change his form at will Protandrous ; 'Gr. proteros, before, and andros, male Protogynous ; Gr. proteros, and gune, female Prothallium ; Gr. proteros, and thallos, a shoot 576 GLOSSARY OF TERMS Protoneme; Gr. protos, first, and nema, a thing spun, a thread Protophyte ; Gr. protos, and phuton, a plant Protoplasm ; Gr. protos, and plasmct, that which has been formed Pseudocarp ; Gr. pseudos, false, and karpos, fruit Pseudopodia ; Gr. pseudos, and podos, foot Pulvinus; Lat. a cushion Pyxis ; Gr. puxidion, a little box Rachis ; Gr. the spine Radicle ; Lat. radix, a root Raphides ; Gr. raphis, a needle Reniform ; Lat. ren, a kidney, and forma, form Replum ; Lat. replum, the leaf of a door Reticulated ; Lat. reticulum, a small net Retuse ; Lat. re, back, and tundo, I hammer Revolute ; Lat. revolutus, rolled back Rostellum ; Lat. diminutive of rostrum, a beak Runcinate ; Lat. runcina, a saw Saccate ; Lat. saccus, a bag Sagittate ; Lat. sagitta, an arrow Saprophyte ; Gr. sapros, rotten, and phuton, a plant Sarcocarp ; Gr garkos, flesh, and karpos, fruit Scalar! form ; Lat. scala, a ladder Scape ; Lat. scctpiis, a stalk Schizocarp; Gr. schizo, to split, and karpos, fruit Sclerenchyma ; Gr. skleros, hard, and enchuma, anything poured or put in Secundine ; Lat. secundce, second Sepal ; Fr. sdpale, invented term to correspond with petale Septicidal ; Lat. septum, an enclosure, and ccedo, to cut Septifragal ; Lat. septum, and frango, to break Sessile ; Lat. sessitis, sitting Sorus ; Gr. soros, », heap Spadix ; Lat. a palm-branch Spathe ; Gr. spathe, a broad blade Spathulate ; Lat. spathula, a broad slice Spermocarp ; Gr. sperma, seed, and karpos, fruit Sporange ; Gr. sporos, seed, and ayyeion, a vessel Spore ; Gr. spora, seed Sporocarp ; Gr. sporos, and karpos, fruit Sporogenous ; Gr. sporos, and yenao, to produce Sporophyll ; Gr. sporos, and phullon, a leaf Sporophyte ; Gr. sporos, and phuton, a plant Stamen ; Lat. a fibre Stigma ; Gr. stigme, a point Stomate ; Gr. stoma, a mouth Style ; Lat. stylus, a stake Subulate ; Lat. subula, an awl Synantherous ; Gr. sun, together, and anther Syncarpous ; Gr. sun, and karpos, fruit Synergidae ; Gr. sun, and ergon, work Testicular ; Lat. test is, a testicle Tetraspore ; Gr. tctra, four, and sporos, seed Thallophyte; Gr. thallos, a shoot, and phuton, a plant Tomentose ; Lat. tomentum, down Trichogyne ; Gr. trichos, hair, and f/une, female Truncate ; Lat. trunco to maim or cut off Urceolate ; Lat. urceus, a pitcher Utricuiar ; Lat. utriculus, a little bottle Vernation ; Lat. ver, the spring Versatile ; Lat. versatilis, revolving Verticillate ; Lat. verticillis, a little whorl Xanthic ; Gr. a-anthos, yellow Xylem ; Gr. xulon, wood or timber Zoophilae ; Gr. zoon, animal, and phileo, to love Zoospore ; Gr. zoon, an animal, and sporos, seed Zygote, Zygomorphic ; Gr. zeugnumi, I join, and morphe, a shape ERRATA Page 49— By the turning of a numeral in printing, the chemical formula for Glucose is made to read C6H,,O9 ; it should be C6HI2O6, as correctly given on page 44. Plate III— Glory Pea (Clianthus dampieri). The popular name belong (C. puniceus) ; we are informed that it is not used in connection with tl to the New Zealand species Australian species. Page 445 — Fig. 549 should, strictly speaking, be named Snee~.eivort Yarrow, to distinguish it from Achillea millefolium, the Milfoil Yarrow. INDEX Pages i-viii and 1-288 will be found in Vol. I. ; pages 289-576 in Vol. II. (Scientific names of plants printed in italics.) Abies canadensis, 66 Abnormal flowers, 324, 325 Absorption, 96 Abutilon, 445 Acacia, 232, 256, 280, 417, 478, 485 Acanthus, 302, 477 Accrescent calyx, 337 Acer, 49, 178, 180, 198, 270, 493 Aceras, 433 Achillea, 445 Achene, 488 Achlya, 537 Acicular leaf, 273 Acid sap, 98 Aconitum, 180, 253, 260, 336 Acotyledons, 172 Actcea, 261 Actinomorphic flowers, 340 Acuminate apex, 274 Acute apex, 274 Adansonia, 1$1 Adder's-tongue Fern, 509 Adhesion, 333 Adnate anther, 356 Adonis, 394 Adventitious buds, 148 Adventitious roots, 168, 188 jEcidium, 550 ^sculus, 66, 175, 245-247, 257, 479, 482 ^Estivation, 329 ^Ethalium, 572 Agapanthus, 395 Agaricineae, 542 Agaricus, 149 Agarum, 286 Aggregate fruits, 474 Agrimonia, 484 Agrimony, 484 Agrostemma, 45, 269 Ake, 350 Alaria, 558, 560 Albuminous seed, 170, 468 Alder, 415 Aldrovanda, 122 Aleurone grains, 53, 57, 85, 134, 146, 166, 556 n—19 Algae, red, 146, 556 ; brown, 560 ; green, 561 ; con- jugate, 564 Allium, 61, 288 Allogamy, 334 Almond, 64 Alnus, 415 Alocasia, 443, 444 Aloe, 65 Alpine Liane, 335, 336, 412 Alpine Madwort, 289, 295 Alternate leaves, 270 Alternation of generations, 390 Althcea, 329 Alyssum, 289 Amanita, 536, 542, 544 American Laurel, vii Amoeba, 8, 9 Amorphophallus, 316, 393 Ampelopsis, 401 Amplexicaul leaf, 262 Anacardiacese, 66 Anagallis, 270, 274, 477 Ananassa, 474 Anastatica, 485 Anatropous ovule, 464 Andreaceae, 392 Androecium, 354 Andropogon, 64, 142 Androsace, 341 Anemone, 316, 414, 417 Anemophilae, 448 Angiosperms, 89 Animal and plant mimicry, 2-6 Annual plants, 218 Annual rings, 211 Annular cells, 36 Annulus, 506 Anther, 321 Antheridium, 164, 166, 505 Antherids, 500, 554, 557 Anthers : adnate, 356 ; basi- fixed, 356 ; dorsifixed, 356 ; extrorse, 356 ; forms of, 354 ; innate, 356 ; in- trorse, 356 ; sessile, 356 ; versatile, 354 577 Antherozoid, 506, 510, 554 Anthocyanin, 282 Anthodium, 318 Anthornis, 446 Anthoxanthum, 262, 264 Anthurium, 399 Anthyllis, 254 Antiaris, 54 Antipodal cells, 466 Antirrhinum, 318, 322, 329, 362 Ants and Milk-sap of Let- tuce, 46 Apocarpous pistils, 333 Apocynum, 364 Apogamy, 506 Apospory, 505 Apple, 337, 357, 473 Aquatic plants, 281 Aquilegia, 345, 348, 478 Arachis, 58, 478, 484 Aralia, 386, 393 Araucaria, 88 Araujia, 432 Archangel, 327 Archegone, 500, 510 Archegonium, 164, 166, 505 Archespore, 504 Arcyria, 573 Aretia, 341 Argemone, 378 Arillus, 496 Aristolochia, v, 268, 356, 374, 384, 404, 424 Armillaria mellea, 144, 145 Aroids, 136, 286 Aromatic oils, 62, 65 Arrow-grass, 461 Arrow-head, 268, 270, 275, 369 Artemisia, 186 Artillery-plant, 460 Artocarpus, 39, 45, 474 Arum, 42, 45, 131, 136, 140, 172, 313, 316, 317, 394, 400, 425 Asarum, 403 Asci, 548 Ascidiform leaf, 279 578 INDEX Asclepias, 408 Ascomycetes, 537, 548 Ash, 254, 368, 369 Ash-leaved Seaweed, 559 Aspen, 64, 300, 448 Asperula, 221, 227 Aspidistra, 376, 385 Aspidium, 505 Asplenium, 246, 249, 500, 505, 511 Assimilation, 130 Astragalus, 56 Athyrium, 71, 167, 505 Atragene, 336, 412 Attar of Roses, 64 Auriculate leaf, 274 Autogamy, 334 Auto-Puccinia, 550 Avena, 45, 316, 317 Awl-shaped leaf, 272 Awn, 317 Axillary buds, 248 Axillary flowers, 312 Azolla, 502 Bacilli, 12, 14, 566 Bacteria, 14, 26, 566 Ballota, 493 Balm of Gilead, 70 Balsamodendron, 70 Balsam Poplar, 66 Balsam Tree, 193 Balsams, 37, 66, 416, 442, 470, 494 Bamboo, 55, 222, 225 Bambusa, 55, 222 Banana, v, 70 Baneberry, 261 Banyan, 192, 193, 236 Baobab, 181 Barbed bristles, 304 Barberry, 1 70, 405, 409, 430 Barley, 1, 2, 168 Basal style, 357 Basidia, 544 Basidiomycetes, 537 Basifixed anther, 356 Bast-fibres, 78 Bast-tissues, 208 Batrachospermum, 557 Bauhinia, 216, 220 Bay-tree, 246 Bean, 26, 169, 172, 214, 226, 416 Beard Moss, 529 Bedeguar, 304, 309 Bedstraws, 221, 309 Beech, 250, 305, 489 Bee Orchis, 3, 6 Beetroot, 46, 48 Beggiotoa, 566 Begonia, 248, 272, 324, 326, 332 Bellis, 266, 273, 313, 325, 350 Bell-shaped corolla, 342 Berberis, 170, 405, 409, 430 Bermuda-grass, 188 Berry, 486 Bertholletia, 480 Beta vulgaris, 46, 48 Betula, 65, 198, 201, 203, 497 Biennial Plants, 218 Bignoniacese, 493 Bindweed, 235, 317, 329 Bipinnate, 256 Birch, 65, 198, 201, 203 Bird-pollination, 444 Bird's-eye Primrose, 389 Bird's-foot Trefoil, 362 Bird's-nest Fungus, 546 Birthwort, v, 356, 374, 384 Biserrula, 498 Bisexual flowers, 368 Biternate, 261 Bitter Cress, 373 Bitter Cucumber, 496 Bittersweet, 228 Blackberry, 474 Black Horehound, 493, 494 Blackthorn, 224, 229, 300 Blackwood-tree, 232 Bladderwort, 106-112 Bladder Wrack, 562, 565 Blade of leaf, 254 Bleeding Heart, 320 "Blood Portent," 14 " Bloom " of leaves and fruit, 66 Blue-bell, 332 Blue-bottle, 492 Boehmeria, 62 Bog-moss, 33 Boletus, 544 Bomarea, 126, 132 Bombax, 236 Borage, 394 Borago, 394 Boswellia, 70 Botany, meaning of the term, 6 Bo-tree, 242 Botrychium, 508, 509 Bottle-tree, 222 Box, 327 Bracken, 504 Bracteate flowers, 314 Bracte, 314 Bramble, 199, 200, 224, 226, 238 Brassica, 58, 169, 180, 289, 295 Brazil-nut, 480 Bread-fruit, 44, 474 Brefeldia, 149, 570, 572 Broom, 187, 188 Broomrape, 151, 153, 155,253 Brown Algae, 560 Brownea, 444 Brownian Movements, 565 Brugmansia, 445 Brunsvigia, 214, 219 Bryonia dioica, 226, 231 Bryony, Black, 228, 237, 254 Bryony, White, 226, 231 Bryophyllum, 248, 250, 252 Bryophyta, 522 Bubonic Plague Bacillus, 12, 14 Buckbean, 35, 41 Buckler Ferns, 507 Buds : adventitious, 248 ; axillary, 248 ; epiphyllous, 248 ; root, 248 ; terminal, 248 Bud-scales, 246 Bulbils, 248, 518 Bulbs, 212 Bulrush, 453 Bupleurum, 264, 266, 269 Burweed, 484, 485 Bush-rope, 216, 220 Butcher's Broom, 222 Butcher's Broom Helwingia, 250 Butomus, 26, 31 Buttercup, 179, 181, 317, 321, 333, 340, 342, 368, 409 Butterworts, 102-105, 108 Buttress-tree, 200, 217 Buxus, 327 Cabomba, 281 Cactaceae, 27, 33, 37, 46, 58, 126, 225, 237, 253 Cactus, 27, 33, 46, 58, 288 ; Old Man, 58 ; Monster, 67, 237 Caducous calyx, 337 Cakile, 186 Caladium, 324 Calamus, 222, 230 Calceolaria, 346 Calceolate corolla, 348 Calendula vulgaris, 138 Calla, 361, 400, 441, 442 Callithamnium, 557 Calluna, 447 Caltha, 362 Calypter, 164, 524 Calystegia, 235 Calyx, 321 ; accrescent, 337 ; caducous, 337 ; decidu- ous, 337 ; dentate, 342 ; galeate, 336 ; globose, 338 ; persistent, 336 ; saccate, 338 ; spurred, 336; tubular, 338 Cambium, 129, 208 Camellia, 329 Campanula, 342, 347, 361, 425 Campanulacese, 382 Campanulate corolla, 342 Campion, White, 340 Campylotropous ovule, 465 Candle-snuff Fungus, 547,549 Candytuft, 482, 486 INDEX 579 "Cane, 230 Ceropegia, 234, 240, 425 Columbine, 345, 348, 478 Canna, 45 Ceterach, 246 Columel, 506 Canose, 48 Cetraria, 533 Comatricha obtusata, 15 •Canterbury Bell, 361 Chara, 552, 553 Comfrey, 407, 414 •Caoutchouc, 50 Characeae, 553 Comma Bacillus, 12, 568 Capillitium, 571 Cheiranthus, 318, 338 Commiphora, 70 •Capitulum, 318, 350, 554 Chelidonium majus, 49, 50, Compass-plant, 290 Capsella, 262, 375, 381, 465, 248 Complete flowers, 369 482 Cherry, 252, 256, 257, 313, 416 Compositae, 353, 369, 382 Capsule, 474 Chestnut, 28, 240 Composite flowers, 350 •Carbon, 57, 93 Chicory, 45, 48 Compound leaf, 254 •Carbon dioxide, 94 Chlora, 264 Compound pistils, 332 Carbonic acid, 94, 96 Chlorella, 400 Compound umbel, 318 •Cardamine, 248, 253, 373, Chlorophyceae, 561 Conceptacles, 561 393, 413 Chlorophyll, 38 Conditions of plant life, 178 Carduus, 302 Chondrus, 558 Conduplicate vernation, 250 •Carex, 184, 459 Christmas Rose, 195, 246 Cone, 318 Carina, 350 Chrysanthemum, 350, 352 Cone-bearing plants, 36, 66 Carlina, 492 Cichorium, 45, 48, 269 85, 224 •Carline-thistle, 492 Cicuta, 70, 72 Confervoideae, 562 Carludovica, 228 Cinquefoil, 265, 268 Coniferce, 36, 66, 85, 173, 224 Carnation, 340 Circcea, 326 Conifers, 273 Carpels, 321, 332 Circinate vernation, 250, 508 Conjugatae, 564 Carpinus, 461, 497 Circular aestivation, 329 Conjugates, 564 •Carpogone, 557 Circulation, 20 Conjugation, 76 Carpophore, 493, 538 Circumnutation, 214, 233 Conjugation of cells, 76 Carrageen, 558 Cirsium, 470 Connate leaf, 264 •Carrot, 177, 180- 332, 336 Cistus, 72 Connective, 321, 354 Caryophyllaceae, 66 Citric acid, 46 Conspicuousness of flowers , Caryophyllaceous corolla, 340 Citrullus, 496 390 •Caryopsis, 488 Cladodes, 222 Convallaria, 210, 314 Cassia, 446 Cladonia, 75, 530, 532 Convoluta, 38 Castalia, 328, 464 Clarkia, 361 Convolute vernation, 250 Castanea, 367, 462 Clary, Wild, 33 Convolvulaceae, 317 'Castor-oil Plant, 58, 498 Clavaria, 538, 545, 549 Convolvulus, 329, 342, 345 Catasetum, 408, 409, 435 Claviceps, 541, 549 Coprinus, 163 Catchfly, 340, 365 Clawed petals, 338 Corallina, 553, 556, 557 Caterpillar-plant, 478, 481 Cleavers, 484 Cordate leaf, 264 Catkin, 318. Cleistogamic flowers, 370 Cord Moss, 525 Cat's-foot, 265 Clematis, 20, 78, 226, 234, Cordyceps, 156-159, 549 Caudex, 214 326, 328, 335 Cork, 13, 31 •Caudicles, 433 Climbing Cobsea, 373, 378 Corms, 213 •Cauline leaf, 272 Climbing Palms, 230 Corn-cockle, 45, 269, 474, 496 Caulotretus, 218 Climbing plants, 226 Corn-spurrey, 269 •Cedar, 83, 84, 85, 242 Closterium, 565 Cornus, 314, 327 Cedrus, 83, 84, 85, 242 Clover, 92, 260, 362 Corolla, 321 Celandine, 49, 50, 248 Cloves, 66 Corollas : calceolate, 348 ; •Celandine, Lesser, 182 Club-mosses, 504, 514 campanulate, 342 : cary- •Celery, 41 Club-rush, 226 ophyllaceous, 340 ; cruci- Cell-communities, 73 Clusia, 193, 194 form, 338 ; gamopetallous, Cell-division, 9, 73, 76 Cluster Cups, 546, 550 342 ; gibbous, 348 ; globose, Cells, 12, 24 Cluster Pine, 186, 189 348 ; hypocrateriform, 341 ; •Cells : annular, 36 ; pitted Cnicus, 264, 265, 299 infundibuliform, 342 ; labi- or dotted, 32 ; reticulated, Cobcea, 373, 378 ate, 344 ; ligulate, 352 ; 36 ; spindle-shaped, 32 ; Coccus, 566 mitraeform, 349 ; papilion- spiral, 33, 36 ; spiro-annu- Coco-nut, 170, 486 aceous, 352 ; paracorolla, lar, 36 ; stellate, 28 Cocos, 170, 486 353; personate, 344; rosa- •Cellulose, 29, 54 Ccelogyne, 380, 382, 405 ceous, 340 ; rotate, 341 ; Gentaurea, 262, 325, 364, Coffea, 170 tubular, 341 ; urceolate, 371, 377, 492 Coffee, 170 349 Ceoma, 552 Cohesion, 330 Corona, 353 •Cephaelis, 182 Coix, 490 Cortex, 180 Cephalotus, 6, 116, 279 Colchicum, 476 Corticium, 545 •Cerasus, 252, 416 Collective fruits, 474 Coryanthes, 418, 438 -Ceratopteris, 249 Collenchyma, 82 Corylus, 416, 456, 488, 491 Delabechea, 222 Elaters, 512, 571 Delesseria, 557, 559 Elecampane, 45 Delphinium, 336, 339. 390, Elder, 34 409, 478, 481, 496 Elk's-horn Fern, viii Dentate margin, 274 Elliptical leaf, 256 Desmanthus, 281 Elm, 207, 308 Desmid, 26, 564 Elodea canadensis, 22, 40 Desmodium, 293, 298 Elymus arenarius, 184 Devil's-fig, 378 Emarginate, 265 Dewberry, 471 Embryo, 466 Dextrose climbers, 226 Embryo-sac, 466 Diadelphous stamens, 332 Enchanter's Nightshade, 326. Dianthus, 25, 317, 327, 340 Endocarp, 473 Diastase, 133 Endoderm, 180 Diatomaceae, 565 Endosmose, 121 Diatoms, 26, 565 Endosperm, 466, 520 Dicentra, 318, 320 Endospore, 518 Dichogamy, 382 Entire leaf, 254 Dicotyledons, 78, 172, 206, Entomophilce, 442 209 Eperua, 444 Dictamnus fraxinella, 141 Ephedra, 186 Digitalis, 333, 343, 378 Epicalyx, 337 Digitate leaf, 257 Epicarp, 473 Dioecious plants, 370, 526 Epidermis, 85, 205 Dioncea muscipula, 98, 105 Epigynous flowers, 357 Dioscorea, 212 Epilobium, 372 Dipsacus, 264, 267, 297, 302 Epipactis, 421 Discomycetese, 548 Distichous leaves, 253 Epiphragm, 526 Epiphyllous buds, 248 " Division of Labour," 28 Epiphytes, 193 Docidium, 565 Epiphytic Club-mosses/ 51 6> Dock, 250 Epispore, 510, 518 " Doctrine of Signatures," 532 Equisetacea?, 504, 512 Dodder, 152, 153, 173, 253 Equisetina?, 504, 512 Dog-lichen, 532, 533 Equisetum, 78, 512--515 Dog-rose, 44, 254, 301, 333 Ercilla, 228 Dogsbane, 364 Ergot, 540, 549 Dog's Mercury, 212 Erianthus, 209, 210 Dogwood, 314, 327 Erica, 349 INDEX 581 Eriophoron, 453 Flower odours, 304 Erodium, 423, 424 Flowers and insects, 312 Eryngium, 184, 186 Foliose Hepatics, 526 Erythrina, 444 Follicle, 478 Eschscholtzia, 337 Fames, 69, 534, 538, 544 Essential floral organs, 321, Fontinalis, 165 369 Forget-me-not, 313, 327, 376 Eucalyptus, 236, 408 Forked Seaweed, 563 Eucalyptus, 231 Foxglove, 333, 342, 343, 378 Euphorbia, 53, 54, 76, 77, Fragaria, 214, 223, 337 81, 142, 152, 225, 230, Frankincense, 70 253, 288, 300, 396, 397, 414 Fraxinus, 254, 368, 369 Evergreens, 273 Free cell formation, 76 Evernia, 527 Fronds, 284 Exalbuminous seed, 170, 468 Fuchsia, 61, 310 Exosmose, 121 Fucus, 555, 561, 565 Exospore, 578 Funaria, 525 Extine, 466 Fundamental tissue, 205 Extrorse anther, 356 Fungi, 85, 160, 166, 172, 254; luminous, 143, 147, Fagus, 250, 489 148; slime, 393 Fairy Clubs, 549 Furcellaria, 563 Fall of the Leaf, 310 Furze, 188 False Cyperus, 459 False Dittany, 141 Galactodendron, 53 Fasciation, 309 Galanthus, 359, 360 Fascicle, 318 Galbanum, 70 Ferns, 165, 166, 172, 250, Galeate calyx, 336 254, 255, 504 Galium, 221, 309, 484 Fertilization, 466 Galls, 301-311 Ferula, 70 Gametangia, 561 Festuca, 302 Gamete, 466, 537, 561 Feverfew, 45 Gamopetalous corolla, 330 Fibrilla?, 18 Gamosepalous calyx, 330 Fibro-vascular bundles, 85 Garden Convolvulus, 373, Fibro- vascular tissue, 85, 205, 376, 392, 394 208 Garrya elliptica, 86, 90 Ficus, 61, 192, 193, 242, 246, Gasteromycetese, 546 248, 386, 397 Geaster, 537, 546 Fig, 388, 397 Genista, 224, 428 Fig, Wild, 160 Gentian, 180, 317, 362 Figwort, 348, 350 Gentiana, 180, 317 Filament, 321, 356 Geranium, 374, 382, 494 Filices, 250, 502, 504 Germination, 168 Filicinse, 504 Germ-tubes, 537 Filiform leaf, 268 Gibbous corolla, 348 Filmy ferns, 506 Gill-by-the-Ground, 265 Fir-cone, 253 " Gills," 542 Fission plants, 12 Ginkgo, 88 Fistular leaves, 288 Gladiolus, 213 Fixed oils, 54 Glands, 84 Flag, 210, 268 Glandular hairs on calyx, Flagella, 9 364 Flamingo-flower, 399 Gleba, 548 Flax, 58 Gleditschia, 280 Flint, 32 Gleichenia, 249 Floral adhesion, 333 Floral envelopes, 321 Glittering Toadstool, 163 Globoids, 53, 57 Floral forms, 312 Globose calyx, 338 Floral number, 330 Globose corolla, 348 Floral variation, 330 Glomerulus, 318 Floral whorls, 330 Gloxinia, 248 Florets, 313, 350 Glucose, 49 Florideae, 146, 449, 556 Glumes, 317 Flowering Rush, 26 Gluten, 57 Flowerless plants, 29, 500 Gnaphalium, 6 Goat's-beard, 316, 319, 364 366, 490 Goat's-thorn, 56 Godwinia, 282, 284 Goodyera, 431 Gooseberry, 337 Goose-grass, 484 Gossypium, 13, 446 Gourd, 487, 489 Graminese, 168, 172, 250, 354 Grape, 463 Grape-sugar, 49 Graphis elegans, 85 Grapnel-plant, 485 Grasses, 181, 211, 250, 261, 288, 317, 354 Grass of Parnassus, 354 Grass-wrack, 449 Green Algse, 561 Green Mould, 22 Ground Ivy, 265, 268, 272 Ground-nut oil, 54 Groundsel, 262, 376 Ground tissue, 85, 205 Guard-cells, 125 Gum-arabic Plant, 478, 485 Gum tragacanth, 56 Gymnaic acid, 48 Gymnema, 48, 53 Gymnogramme, 505 Gymnosperms, 88, 89, 496 Gymnosporangium, 551, 552 Gymnostomous sporange, 391 Gynandrous adhesion, 334 Gyncecium, 357 Gyrophora cylindrica, 88 Haastias, 6 Habenaria, 426, 435 Hcematococcus, 8 Hairs of plants, 289, 295 Halesia, 194 Halimeda, 558 Halymenia, 561 Hard-fern, 501, 504 Hard-heads, 371 Hare's ear, 264, 266, 269 Harpagophytum, 485 Hart's-tongue, 249, 504 Hart- truffle, 158, 159, 549 Hastate leaf, 268 Haulm, 288 Hawthorn, 224,~550 ,Hay Maid, 265 " Hazel, 416, 456 Heartsease, 170 Heath, 349, 350 Heather, 447 Hedera, 190, 191, 192, 196, 214, 226, 241, 258 Helianthus, 45,^138, 212 Hellebore, 258, 259, 336 Helleborine, 421 Helleborus, 195, 246, 258, 259, 336 Helminthia, 492 582 INDEX? Helwingia, 250 Hemlock Spruce, 66 Hemlock Stork's-bill, 423,424 Hemlock Water-dropwort, 63, 72 Henbane, 336, 338, 343, 382 Henbit, 370 Hepaticse, 85, 502, 522, 524 Herbaceous plants, 216, 218 Herb-paris, 261, 313, 314 Herbs, 218 Hermaphrodite flowers, 368 Herminium, 440 Hesperidium, 488 Hesperis, 397 Hetercecism, 550 Heterophyllous leaves, 268 Hetero-Puccinia, 550 Heterostylism, 385 Hevea, 50 Hilum, 169 Hip, 44 Hippeastrum, 125 Hippophae, 461 Hirneola, 540, 545 Holly, 246, 253, 272, 273, 288, 296, 298, 301 Hollyhock, 329 Holocyclic stems, 220 Honesty, 338 Honey, 406 Honey-flower, 418 Honey-guides, 340, 404 Honey- locust Tree, 280 Honeysuckle, 226, 239, 264, 266, 341, 364 Hook climbers, 226 Hookeria, 145 Hop, 25, 30, 34, 226, 233, 295 Hop Hornbeam, 497 Hop Trefoil, 92 Hordeum, 1 Horehound, 289, 295 Homnimtm, 391 Hornbeam, 461, 497 Horn of Plenty Fungus, 548 Horse-chestnut, 66, 175, 177, 245-247, 257, 366, 479, 482 Horsetails, 78, 166, 504, 512-515 Humulus,25, 30, 34, 226, 233 Huntsman's-horn, iv Hyacinth, 213, 218, 396 Hyacinthus, 218, 396 Hydrangea, 351 Hydrogen, 57, 96 Hydrophilae, 448 Hydropteridese, 504 Hymenium, 542 Hymenomycetes, 542 Hymenophylleae, 502, 506 Hyoscyamus, 336,338, 343,353 Hypanthodium, 318 Hypericum, 325, 329 Hyphse, 550 Hyphomycetese, 553 Hypogynous flowers, 357 Hysteriacese, 549 Iberis, 482, 486 Iceland Moss, 533 Ilex, 246, 253, 273, 288, 298, 301 Imbricated aestivation, 329 Impari-pinnate leaf, 256 Impatiens, 37, 372, 416, 442, 446, 470, 494 Imperfect flowers, 369 Incomplete flowers, 369 Indian Crocus, 380, 382, 405 Indian Cups, 113 Indiarubber, 50, 61, 246, 248 Indefinite inflorescence, 317, 381 Indehiscent fruits, 474, 485 Indusium, 504, 506 Inflorescence, 313 Infundibuliform corolla, 342 Infusoria, 26 Innate anther, 356 Inorganic compounds, 129 Insectivorous'plants, 102-120 Integuments of ovule, 465 Intercellular spaces, 124 Interfascicular cambium, 209 Internodes, 220 Intine, 466 Introrse anther, 356 Inula, 45 Inulin, 45, 54 Involucre, 316 Involute vernation, 250 Ipomaa, 373, 376, 392, 394 Iriartta, 189 Iridacece, 214 Iris, 61, 210, 214, 268, 476 Irregular flowers, 340 Irregularity of form, 402 Irritability, 430 Isoetes, 502, 518, 520 Italian Reed. 76 Ithyphallus, 61 Ivory-nut, 170 Ivy, 190, 191, 192, 196, 214, 226, 241, 258 Jak-fruit, 39 Jania, 557, 558 Jasminum, 1, 64 Jalropha, 44, 498 Jerusalem Artichoke, 45, 212 Jessamine, i, 64 Jew's-earFungus,540,545,548 Job's-tears, 490 John-go-to-bed-at-noon, 364 Juglans, 61, 62, 482 " Jumping Beans," 470 Jumping leaf, 249, 251 Juncus, 26 Juniper, 277, 551, 552 Juniperus, 277 Jurinea, 364 Kalmia, vii, 406, 430 Kamschatkan Lily, 462" Keel, 350 Khus-Khus, 64, 142 Kidney-shaped leaf, 265- Kidney Vetch, 254 Kieselguhr, 566 Kitasato bacillus, 14 Knapweed, 325, 377 Kon-tree, 202 Labiate corolla, 344 Laburnum, 330 Laciniated leaf, 286 Lactuca, 52, 300 Ladanum, 70 Lady Fern, 71, 167 Lady's Smock, 248, 253 Lady's Tresses, 419 Laminaria, 294, 554, 560 Lamium, 327, 344, 346, 354,. 370 Lanceolate leaf, 254 Land-turtle's Ladder, 216 Lapageria, 444 Laportea, 278, 279 Larch, 80, 85 Larch-leaf Rust, 552 Larix, 80, 85 Larkspur, 336, 339, 390, 409, 481, 496 Lateral style, 357 Latex, 49, 53 Lathrcea, 118, 120, 121, 123 Lathyrus, 226 Lattice-leaf Plant, 284, 285 Laurel, 416 Laurus, 246 Lavandula, 56 Lavender, 56, 62, 72 Laver, 558 Layer of separation, 310 Leaf-bud, 245 Leaf climbers, 226 Leaf forms, 254 Leafless plants, 254 Leaf nectaries, 416 Lecanora parella, 86 Lecidea, 534 Lecythis, 477 Leersia, 372 Legume, 478 Legumin, 57 Leguminosse, 296 Leitneria, 356 Lens-shaped cells, 86 Lenticels, 129 Leocarpus, 572, 573 Leontopodium, iii, 314 Lepidium, 169 Leptodermis, 496, 498- Leptothrix, 566 Lessonia, 237, 560 Lettuce, 46, 300 Leukop lasts, 42 Liantesse, 122 INDEX 583 Liber, 209 Lichen-forming Fungi, 532 Lichens, ii, 38, 85, 86, 527, 534 Lignin, 29 Ligulate corolla, 350 Ligule, 254 Ligustrum, 264, 269, 270, 327 Lilac, 270, 377 Lilium, 138, 314, 409 Lily, 172, 213 Lily of the Valley, 210, 314 Lime-galls, 306, 309 Lime-secreting plants, 556 Lime-tree, 57, 61, 84, 242, 280, 317, 329 Linaria, 344, 349, 481, 483 Linear leaf, 254 Linseed-oil, 58 Linum, 58 Lip-cells, 506 Liriodendron, 246, 250, 274 Listera, 401, 420, 421 Lithothamnium, 556, 558 Liverworts, 85, 126, 134, 166, 172, 522, 524, 528 Lobelia, 332 Loculi, 476 Loculicidal dehiscence, 476 Lodoicea, 486 Lomaria, 501, 504 Lomentum, 478, 485 London Pride, 266, 271 Lonicera, 239, 264, 266. 341, 364 Loosestrife, 312 Loranthacese, 233 Loranthus, 176 Lotus, 362 . Lousewort, 361, 365 Lucerne, 266, 482 Luminosity of plants, 137— 151 Luminous Mosses, 142 Lum-tree, 200 Lunaria, 338, 485 Lungs of Oak, 532 Lupins, 289, 294 Luzula, 318 Lychnis, 340, 474, 496 Lycogala miniata, 16 Lycoperdon, 535, 546 Lycopodiacese, 504, 514 Lycopodinae, 504 Lycopodium, 501, 514-517 Lyme-grass, 181, 184 Lyrate leaf, 269 Lysimachia, 312 Lythrum, 363, 377, 378, 386 Macrocystis, 237, 560 Madder-plant, 125 Madwort, 289, 295 Magnolia, 379, 382, 478 Maidenhair Spleenwort, 500 Maiden Pink, 340 Maize, 169, 173 Malacophilas, 442 Malcolmia, 25 Male Fern, 502, 503 Malic acid, 48 Mallow, 270, 336, 494 j Malva, 270, 336, 494 j Mamillaria, 33 Mamures, 228 Mandioc-root, 54 Mandragora, 180 Mandrake, 180 Mangrove, 200 Manihot, 54 Manubrium, 554 Maple, 173, 178, 180, 198, 493 Marattiacese, 508 Marcgravia, 229, 445 Marchantia, 126, 134, 528 Marchantiaceae, 526 Marigold, 138; African, 138 Maritime Pine, 68, 186 Marjoram, 60, 64 Marram, 181, 184, 185, 188, 212, 292 Marrubium, 289 Marsh Cypress, 202 Marsh Marigold, 362 Marsilea, 285, 512 Martagon Lily, 138, 409 Martynia, 482 Marvel of Peru, 289, 295 Master wort, 261 Mat-grass, 302 Matthiola, 481, 482 Matricaria, 45 Mat weed, 292 May-tree, 224 Meadow-cranesbill, 374, 382 Meadow-crocus, 287, 288 Meadow-rue, 256 Meadow-saffron, 476 Meadow-sweet, 323 Medicago, 266, 478, 482 Medick, 266 Medlar, 473, 475 Medulla, 208 Medullary rays, 208 Medullary sheath, 78 Megarrhiza, 466 Megasporange, 510 Megaspore, 510 Melampsora, 552 Melampyrum, 498 Melianthus, 418 Melocactus, 33 Melon, 337 Mentha, 57 Menyanthes, 35, 41 Mericarps, 492 Mericyclic stems, 220 Meristem, 82 Merulius, 540, 542 Mesembryanthemum, 4, 6, 86 Mesocarp, 473 Mesophyll, 502 Mespilus, 475 Metabolism, 54 Metrosideros, 232 Micrasterias, 565 Micrococcus, 566 Micropyle, 169 Microsporange, 510 Microspore, 510 Midrib, 256 Mignonette, 332, 397 Milk-sap, 49, 52 Milk-thistle, 489 Mimosa, 21, 292, 296 Mint, 56 Mirabilis, 289 Mistletoe, 36, 37, 150, 153, 233: Mitraaform corolla, 349 Mitrula, 545 Mnium, 136 Molucella, 336 Monachanthus, 436 Monadelphous stamens, 332 Moneywort, 312 Moniliform pod, 478 Monkey-ladder, 218 Monkey-nut, 58 " Monkey-pots," 477 Monkshood, 180, 260, 262, 336 Monocotyledons, 78, 172, 209- Monoecious plants, 370, 526 Monosymmetrical flowers, 3401 Monstera, 133, 136, 285, 286 " Monstrous " flowers, 326 Moonwort, 508 Mora, 236 Mora-tree, 236 Morchella, 160, 164, 543, 548- Morel, 160, 164, 543, 548 Morning Glory, 373, 376 Morus, 474 Moss " flowers," 514 Mosses, 85, 134, 136, 162, 165, 166, 168, 172, 254, 522, 525 ; luminous, 142, 145 Mossy Pink, 344 Motile plants, 10 Moulds, 22, 534, 536 Mountain-ash, 401 Mucor, 534, 537, 550 Mucilago, 568, 572 Mucronate leaf, 266 Mulberry, 473, 474 Mullein, 289, 291 Multicellular plants, 10 Murlins, 558 Musa, v, 70 Musci, 85, 134, 162, 522 Mushroom, 24, 147, 160, 161, 530 Mustard, 168, 269 Myanthus, 436 Mycele, 530, 540 Mycetozoa, 568 Mycorhiza, 540 584 INDEX Myosotis, 313, 327, 370, 374, 58 ; clove, 64 ; fixed, 54 ; 396 lemon, 64 ; linseed, 58 ; Myristica, 496 olive, 54 ; palm, 54, 58 ; Myrrh, 70 rape or colza, 58 ; turpen- Myxogasters, 149, 568 tine, 64 ; volatile, 56 Myxomycetes, 568 Olea, 58, 242 Olibanum, 70 Narcissus, 353 Olive, 53, 58, 242 Nardus, 302 Olive Seaweeds, 560 Nasturtium, 139, 141, 226, Oncidium, 384 336, 337, 409, 494 Onion, 18, 61, 213, 288 Nectar, 406 Onobrychis, 254 Nectaries, 390, 398, 409 Ononis, 224,» 300 Needle-shaped leaf, 273 Onopordon, 263 Negro's-head Palm, 1 70 Oogones, 554, 561 Nelumbium, 272, 276 Oogonium, 564 Neottia, 437 Oomyceles, 536 Nepenthes, 107, 110-118, 279 Oophyte, 164 Nepeta, 265, 268, 272 Oosphere, 466, 510, 556, 561 Nephrodium, 507 Oospore, 562 Nettles, 61, 212, 296, 303, Opercule, 525 304, 305, 460 Ophioglossaceae, 508 Net-veined leaf, 256 Ophioglossum, 508, 509 Neuropeltis, 317 Ophrys, 3 Neuter flowers, 369 Opium, 50 New Holland Pitcher-plant, Opposite leaves, 270 113 Opuntia, 33, 37, 300, 304 Nicandra, 289, 295 Orange, 490 Night-flowering Stock, 397 Orbicular leaf, 270 Nitella, 16, 553 Orchids, 3, 6, 22, 34, 41, 172, Nitrogen, 57, 97 189, 197, 404, 426-440 Nodes, 220 Orchis, 427, 429, 430, 432, 434 Non-nitrogenous compounds, Origanum, 60 57 Ornithogalum, 217 Norfolk, or four-course rota- Ornithophilse, 442 tion, 93, 100 Orobanche, 151, 153, 155 Nucellus, 465 Orthotropous ovule, 465 Nuclear division, 74 Oryza, 45 Nucleoplasm, 18 Osier, 276 Nucleus, 17, 569 Osmundacese, 508 Nut, 486 Ostrya, 497 Nutmeg, 496 Ouvirandra, 284, 285 Nutrition, 92 Ovary, 321, 464, 468 Nymphcea, 328 Ovate leaf, 264 Nymphseaceae, 170, 468 Ovule, 321, 464, 468 Ovuliferous scales, 496 Oak, 23, 24, 28, 32, 59 66 Ovum, 466 173, 240-244, 257, 260, Oxalate of lime, 60 452, 489, 495 Oxalis, 51, 61, 214, 221, 265, Oak-galls, 301-311 290, 296, 372, 373, 468, Oak, Cowthorpe, 241 ; Green- 469 dale, 240, 242 ; in Nor- Oxidation, 134 mandy, 240 ; Salcey, 240 ; Oxlip, 314, 376 Winfarthing, 240, 244 Oxygen, 57 Oar- weed, 294 Oat, 45, 316, 317 Padina, 560 Obcordate leaflet, 265 Pceonia, 372, 478, 481 Oblique leaf, 272 Pales, 317 Oblong leaflet, 266 Palisade-parenchyma, 86 Obovate leaf, 264 Palm, 172 Obtuse apex, 274 Palmately veined, 258 Octastichous leaves, 253 Palmatifid, 258 Odontoglossum, 412 Palmatipartite, 258