GUIDE BRITISH MYCETOZOA EXHIBITED IN THE DEPARTMENT OF BOTANY, BRITISH MUSEUM (NATURAL HISTORY). PRINTED BY ORDER OF THE TRUSTEES. 1895- [PRICE THREEPENCE.] PRESENTED She trustees THE BRITISH MUSEUM BRITISH MYCETOZOA. GUIDE BRITISH MYCETOZOA EXHIBITED IN THE DEPARTMENT OF BOTANY, BRITISH MUSEUM (NATURAL HISTORY). BY ARTHUR LISTER, F.L.S. PRINTED BY ORDER OF THE TRUSTEES. 1895. i}3 Printed by Hazell, Watson, & Viney, Ld., London and Aylesbury. PREFACE. THE collection of British Mycetozoa, and the series of coloured drawings explaining their structure, exhibited in the Botanical Gallery, have been presented by Mr. Arthur Lister, the author of this Guide. All known British Myceto- zoa are described briefly, and it is hoped that this account will serve as an introduction to the systematic study of the group. In preparing his Monograph of the Mycetozoa, based on the collection in the British Museum, Mr. Lister generously enriched the national herbarium by the gift of numerous specimens which had the special value of having been named after comparison with type specimens in the herbaria of the Royal Gardens, Kew ; the Royal Botanic Gardens, Edinburgh, Strassburg, Paris, Christiania, Leyden ; the collections of Messrs. Phillips and Massee, in this country, and with specimens furnished by Dr. Rex, Prof. Farlow of Harvard University, Prof. Macbride of the State University of Iowa, and Mr. Morgan of Ohio. For the purpose of ready microscopic examination Mr. Lister also prepared and presented to the Trustees eight hundred and thirty-two mounted slides, illustrating the British Museum collection of Mycetozoa, and they are preserved in a cabinet in the Cryptogamic Herbarium for consultation by students. The present Guide is based on the study of this valuable material, and in its preparation Mr. Lister has had the ad- vantage of the diligent assistance of his daughter, Miss Gulielma Lister, who has also made the coloured drawings exhibited in the case. GEORGE MURRAY. ERRATUM. On page xx, line 10 trom bottom, /or " forms" read " walls. BRITISH MYCETOZOA. The Mycetozoa are a group of organisms which may be placed in the border-land between the Animal and Vegetable Kingdoms. They are characterised by the constant sequence of three main stages in their life history, viz. : — 1. The firm-walled spore gives birth to a swarm-cell. 2. The swarm-cells coalesce to form a wandering Plasmodium. 3. The Plasmodium ultimately concentrates to form either sporangia, enclosing numerous spores (Endosporeae), or sporoplwres bearing spores on their outer surface (Exosporeae). Many species are quite common, and are found on old decaying stumps and fallen branches in moist woods and shaded gardens ; others inhabit heaps of dead leaves which have lain undisturbed and become soaked with rain. The only stage in which they are con- spicuous is that of the sporangia, when they appear as minute ob- jects, some roundish, about the size of small mustard seeds, others rising in clusters of brown columns on black hair-like stalks, while many take other characteristic forms. The different species display great vari- ety and beauty in the colours they assume, ranging from pure white, golden yellow, bright crimson, and iridescent violet to dark purple and black. The various phases in the life history of the group may be de- scribed as follows : — The swarm-cells emerge from the spores as amoeboid bodies ; they soon acquire a flagellum at the anterior end, and creep in a linear form with the flagellum ex- tended in advance, or swim in the surrounding water with a dancing DlDYMlUM DIFFORME Duby. a. Spore. b. Swarm-cell escaping from the spore- case. c. Newly hatched swarm-cell containing a nucleus, and three vacuoles. d. Flagellated swarm-cell. e. Swarm-cell, with two vacuoles contain- ing bacteria, and produced at the pos- terior end into pseudopodia, to one of which a bacterium is attached. /. Amoeboid swarm-cell. Magnified 720 times. Swarm-cells 8 BRITISH MYCETOZOA. motion occasioned by the lashing movement of the flagellum. They possess a single nucleus and a contractile vacuole. To a large extent the swarm-cells feed on bacteria, which are caught by pseudopodia projected from the posterior end of the body. The bacteria are conveyed into the body-substance, where they are digested in vacuoles which form round them ; there may be one or more digestive vacuoles, each containing several bacteria at one time. The swarm-cells rapidly increase in number by bipartition. When this takes place the flagellum is first withdrawn, and the swarm-cell assumes a globular form; it then elongates, and a constriction occurs at right angles to the long axis. Meanwhile the nucleus is passing through the process of division by karyokinesis, and in the course of a few minutes the two halves of the nuclear plate separate and retreat to the opposite ends of the constricted cell, which now d c j Fig. 2.— Amauroch^te atra Rost. a to/. Successive stages in bipartition ot swarm-cell, accompanied by the divi- sion of the nucleus by karyokinesis. Magnified 1200 times. Drawn from stained preparations in Canada balsam. Fig. 3.— DlDYMIUM D1FFORME Duby. Youngplasmodium, with attendant amceboid swarm-cells, some of which have turned into microcysts < ml : one microcyst is being digested in a vacuole (i>). An empty spore-shell is shown at s. Mag- nified 470 times. divides into two ; each segment soon acquires a flagellum, and resumes the former active state. Microcysts. In all cultivations of germinating spores a number of the swarm-cells, after a short time of activity, become encysted in a globular form as microcysts. In this state they may remain dry for several days, but on water being added the cyst-wall is ruptured and the contents creep out and assume again the motile condition. Frequently the entire group of swarm-cells will change to microcysts, and reawaken in the course of two or three days while still im- mersed in water. A few days after the germination of the spores, the process of bipartition, by which the number of the swarm-cells has greatly increased, ceases. The majority now withdraw the flagellum, and adopt true amceboid movements. These amceboid Plasmodium, bodies collect in clusters, and coalesce to form plasmodia, which may BRITISH MYCETOZOA. be described as masses of naked protoplasm abounding in nuclei and more or less coloured granules. The nuclei at this early stage appear to be those of the individual swarm-cells which have fused together. Careful investigations lead to the conclusion that the vast multiplication of nuclei which takes place during the growth of the Plasmodium results from simple division. Apparently one instance only of division by karyokinesis in this stage of the Plasmodium has been recorded, and of this observation permanent preparations are pre- served (Fig. 5). As the plasmodium increases in bulk by the ingestion of nutritive matter and by the union of small plasmodia, it acquires the remarkable streaming movement peculiar to itself. In the majority of species the plasmodium is white, but there are many in which it is yellow, and in some it is greenish, pink or purple. It penetrates the substance of dead wood or spreads over the surface of dead Badhamia UTKicuLARls Berk. Group of nuclei from actively feeding Plasmodium that covered two pilei ol Auricularia in fourteen hours, show- ing the irregular size of the nuclei and large nucleoli. Stained in picro-carmine and mounted in Canada balsam. Magnified 1200 times. Fig. 5. — Badhamia utricularis Berk. Division of nuclei by karyokinesis in the streaming plasmodium. Magni- fied i2co times. From a preparation stained in satianin, and mounted in Canada balsam. ] 1 leaves, bark, etc., in a network of veins, taking a somewhat fan- shaped outline ; through these veins the more fluid matter in the interior streams constantly in a rhythmic flow. The current con- tinues in one direction for a certain period, usually a minute and a half, when it stops, and after a moment's pause reverses its course, flowing the opposite way for about the same length of time, but rather longer in the direction in which the mass is advancing. It is by this means that the plasmodium creeps forward. The object ot this onward movement appears to be a search for food. If the yellow plasmodium of Badhamia utricularis, which feeds on woody fungi, is cultivated on Stereum hirsutum, placed on a plate and covered with a glass shade, it extends itself over the fungus with a turgid advancing border until it has devoured the more delicate hyphas. Having exhausted the nutriment, it will spread over the 10 BRITISH MYCET0Z0A. plate and the interior of the glass shade. It it is in sufficient quantity, it will in the course of a couple of days cover the glass with a network of veins over an area of perhaps forty or fifty square inches. A piece of fresh Steream, soaked in water, may now be inserted beneath the shade, allowing it to come in contact with one of the smallest veins. In a few hours the whole of the plasmodium will have withdrawn from the sides of the shade, and concentrated itself on the fresh food in a dense yellow mass. The length of time during which the plasmodium will continue to feed and increase in bulk before changing into sporangia differs according to the species, and also to the conditions of its surroundings. Physarum psittatinum, which inhabits the rotten stumps of old trees, appears to pass twelve months in the plasmodium stage ; on the other hand, Didymium diffor»ie will go through the several stages from germina- tion of the spores to the formation of the sporangia in a fortnight. The latter species is very common, and may easily be cultivated. The spores can be sown in water on a thin cover-slip supported over a glass slide by a ring of wet blotting-paper, the required nutri- ment being supplied by two or three slices of the mucilaginous coat of a garden-cress seed. In this moist chamber the whole process of the division of the swarm-cells, their coalescence to form the plas- modium, and the construction of the sporangia, may be watched under the microscope. The plasmodium, if allowed to dry, passes into the sclerotium or resting stage. The sclerotium of Badhamia atricularis is dull orange-red in colour, of horny consistence, made up of a multitude of thin-walled cysts closely packed together ; each cyst is filled with granular protoplasm, among which ten to twenty nuclei are inter- spersed. On being wetted the sclerotium will revive in the course of a few hours and resume the streaming movement. Preserved in a dry state, it will retain its vitality for three or four years, but it is longer in reviving according to the length of time it has remained in the resting condition. The formation of the sporangium may be illustrated by the growth of Comatriclia obtusata, a common species which is often found on the under side of fir planks that have been left to rot on the ground. When the fruiting period arrives, the watery-white plasmodium issues from the wood at a point favourable to the development of the sporangia, and spreads over an area measuring perhaps half an inch across. After a time the plasmodium is seen to concentrate in thirty or forty centres, and in an hour or two each centre has risen into a pear-shaped body with a narrow base, a dark stalk being just apparent through the translucent white substance. In six hours the black hair-like stalk has grown to its full length, bearing at its summit the young sporangium, consisting of a white globule of viscid plasma with a diameter about one-fifth of the length of the stalk. A pink flush now begins to pervade the sporangium, caused by the formation of the dark flexuose branching threads ot BRITISH MYCETOZOA. I I the capillitium (referred to afterwards) extending from the columella to the circumference. The nuclei in the plasma still present the same appearance as those observed in the streaming Plasmodium. In about another hour the nu- clei show the beginning of karyokinetic division (Fig. 6); as the process advances the plasma becomes separated in masses of two spores' capacity (Fig. 7) ; an hour later, and karyokinesis is completed, the nuclei have divided, and the youngspores are forming. As the dark spore - walls are produced the colour of the sporangia rapidly changes, and in about twenty hours after the first concentration of the Plas- modium they have matured and present the appearance of a cluster of minute black pins, with round or oblong heads, standing in regular order on the wood. The sporangia of different species take various forms, such as are represented by the woodcuts illustrating the different genera, with numerous modifica- tions. They may be either symmetrical or irregular in shape, and with or without a stalk ; when sessile and of irregular form, as shown in Fig. 13, they have received the name of plasmodiocarps. piasmodiocarp. When many sporangia .ffithalium. are combined, and their separating forms are imper- fectly developed, the cluster is called an cethalium. When the sporangia are Hypothallus. formed, a membranous or calcareous residuum or hy- pothallus is often left by the Plasmodium, forming a base on which the sporangia are seated. In most genera a capillitium, consisting of a system of threads, Capillitium. MATRICHA OBTUSATA PreilSS. From a stained preparation of a young sporangium, showing the Plasmodium separated into rounded masses about groups of nuclei, which are dividing by karyokinesis ; the nuclear division has reached the "spindle stage"; the spindles are seen in profile in all cases but one, in which the equatorial plate is seen from one of the poles of the spindle. Magni- fied 1200 times. Fig. 7.— COMATRICHA OBTUSATA PreuSS. From a stained preparation of a young sporan- gium, showing: the Plasmodium separated into masses of two spores' capacity round the nuclei, which have almost divided by karyokinesis. Magnified 1200 times. 12 BRITISH MYCETOZOA. is found ; this is constructed before the spores are formed, and in many species extends from the base of the sporangium, or from an extension of the stalk within the sporangium (the columella), to the enclosing wall. It often appears to form a scaffolding, which prevents the shrinking inwards of the sporangium-wall in drying, and thus allows the spores to mature freely and without pressure. The capillitium differs widely in structure in different genera, and is beautifully adapted to assist in the dispersion of the spores on their reaching maturity. In Trichia the capillitium threads lie free among the spores, and, being provided with spirally thickened bands which are strongly hygroscopic, twist and writhe with every change of moisture ; by this action they separate the spores, so that they are easily carried away by the wind ; such free threads are called elaters. In Stanonitis the capillitium springs from the columella, and extends to the surface of the sporangium, where it forms an enclosing net ; the delicate membrane covering the meshes shrivels up on ripening, so that the spores lie in an open-work basket, and are blown by the wind through the openings. In Arcyria the capillitium consists of a dense tangle of branching threads, which, when the ripe fruit dries and the delicate sporangium-wall breaks up, expands to many times the original volume, and in so doing scatters the spores on all sides. Carbonate of lime is usually abundant in the Plasmodium and young sporangia of the species comprised in the subcohort Cal- carinece. In most genera of the order Physaracece these granules are withdrawn from the plasma before the spores are formed, and are deposited partly in the sporangium-wall, and partly in vesicular expansions of the capillitium. These expansions take various shapes ; they are globose, fusiform, or branched, and are sometimes fused together in the centre of the sporangium, forming a pseudo-columella. Lime-knots. In the descriptions of the species they are termed lime-knots. In the Didymiacece the granules in the young sporangia are dissolved at a certain stage, and the salt forms again in crystals on the outside of the wall. The genus Cribraria is one of several in which no capillitium is present, but the upper part of the sporangium-wall consists of an open net through the meshes of which the spores escape. It may be well to repeat what has been already stated, that in the sub-class Endosporccc the formation of spores takes place several hours after the sporangia have assumed their ultimate shape, and is immediately preceded by the division of the nuclei by karyo- kinesis, when each daughter-nucleus becomes the centre of a young spore. Here, as in the case of bipartition of the swarm-cells, true cell-formation takes place, and in both instances it is associated with karyokinetic division of the nucleus, whereas during the growth ot the Plasmodium the almost invariable rule appears to be that the nuclei increase in number by simple division. The sub-class Exosporcce is represented by the single genus BRITISH MYCETOZOA. 13 Ceratiomyxa, and is characterised by the numerous white spores being borne on the outside of columnar or branching sporophores. These are delicate, fragile structures, often covering two or three square inches of the dead wood on which they grow. The surface of the sporophore is mapped out into polyhedral areolae, from the centre of each of which arises a slender stalk bearing a single ellipsoid spore. On placing the ripe spores in water, the mem- branous spore-wall at once slips off, and the naked contents lie for several hours without apparent change, retaining their ellipsoid form. A constriction then takes place at right angles to the long axis, and before division is completed a second constriction of each half occurs; each of the four lobes thus formed again be- comes constricted, and we have eight globular bodies adhering together and ex- hibiting slow amoeboid move- ment ; each of these bodies now produces a flagellum, and the cluster swims away by aid of the lashing flagella. In a short time the swarm- cells separate, and behave, so far as their history has been traced, in the same manner as those of the Endosporea: The colourless Plasmodium inhabits the sub- stance of rotten wood, and exhibits rhythmic streaming with the same intervals of time between the forward and backward flow as in the larger sub-class of the group. The Mycetozoa are remarkably cosmopolitan, a large number of species being found with identically the same characters in Europe, India, the Cape of Good Hope, Australia, and North and South America. Of the hundred and seventy-five species which are represented in the British Museum collection, fifty-six have not yet been recorded from this country, and these have chiefly been obtained from the United States and the Tropics. During the last few years about thirty British species have been added to the list given in Cooke's "Myxomycetes of Great Britain," and it is probable that many more Fig. 8. — Ceratiomyxa mucida Schroet. <7. Spore. b. Spore-contents escaping from the spore-wall. c to i,1. Successive stages in the division of the naked spore into eight. /;. Cluster of eight swarm-cells. Magnified 1200 times. 14 BRITISH MYCETOZOA. will be discovered as fresh workers in different parts of the country take up the study. The sporangia are found at all seasons of the year except in frosty and very dry weather, and every new locality that is searched affords abundant material, frequently including species of special interest which are rare elsewhere. There is perhaps no group of organisms so easily within reach which offers at the present time so rich a reward to microscopic research. SYNOPSIS OF THE ORDERS AND GENERA OF THE BRITISH MYCETOZOA. Sub-class I. — EXOSPOREiE. Spores developed outside the sporophores. Order I. — Ceratiomyxace^. Sporophores membranous, branched ; spores white, borne singly on filiform stalks arising from the areolated sporophore. Genus i. Ceratiomyxa (p. 17). Sub-class II.— ENDOSPORE^E. Spores developed inside the sporangium. Cohort l.—AMAUROSPORALES. Spores violet or violet- brown (ferruginous in Stemonitis ferruginea and S. Smitliii). Sub-cohort I. — CALCARINEAZ. Sporangia provided with lime (= calcium carbonate). Order I.- — Physarace^. Lime in the form ot minute innate granules. A. Capillitium charged with lime throughout. Genus 2. Badhamia (p. 17). B. Capillitium of hyaline threads with lime-knots (see Introduc- tion, p. 12). Genus 3. Sporangia single, sub-globose or plasmodiocarps ; capillitium without free, hooked branches. Physarum (p. 18). Genus 4. Sporangia forming an aethalium. Fuligo (p. 21). Genus 5. Plasmodiocarps ; capillitium with free, hooked branches. Cienkowskia (p. 21). Genus 6. Sporangia goblet-shaped or ovoid ; stalks cartilagi- nous. Crateriion (p. 21). Genus 7. Sporangia ovoid, shining, clustered ; stalks mem- branous. Leocarpus (p. 22). C. Capillitium without lime. Genus 8. Sporangium-wall opaque. Chondrioderma (p. 22). Genus 9. Sporangium-wall hyaline. Diacliaa (p. 24). BRITISH MYCETOZOA. 15 Order II. — Didymiace/E. Lime in superficial crystals deposited outside the sporangium-wall. Genus 10. Crystals stellate; sporangia single. Didymium (p. 24). Genus 11. Crystals stellate ; sporangia forming an sethalium. Spumaria (p. 26). Genus 12. Crystals lenticular. Lepidodcrma (p. 26). Sub-cohort W.—AMAUROCHMTINEJE. Sporangia without lime. Order I. — Stemonitace^e. Sporangia single, provided with a stalk and columella. A. Sporangium-wall evanescent. Genus 13. Capillitium spreading from the columella and form- ing a superficial net. Stcmonitis (p. 26). Genus 14. Capillitium as above, but not forming a superficial net Comatricha (p. 27). Genus 15. Capillitium springing from the apex of the sporan- gium. Enerthenema (p. 28). B. Sporangium-wall persistent. Genus 16. Capillitium radiating from the columella. Lamproderma (p. 28). Order II. — AmaurochvETACEjE. Sporangia combined into an sethalium. Genus 17. Capillitium irregularly branched. Amaurochcete (p. 30). Genus 18. Capillitium with chambered vesicles. Brcfeldia (p. 30). Cohort U.—LAMPROSPORALES. Spores variously coloured, not violet (except in Cribraria violacea). Sub-cohort I. — ANEMINEAt. Capillitium wanting, or not forming a system of uniform threads. Order I. — Heterodermaceje. Sporangium-wall membranous, beset with microscopic round plasmodic granules. Genus 19. Sporangium-wall not forming a persistent net. Lindbladia (p. 30). Genus 20. Sporangium-wall forming a persistent net. Cribraria (p. 31). Genus 21. Sporangium-wall forming numerous parallel ribs. Dktydium (p. 32). Order II. — Liceace^e. Sporangium-wall cartilaginous. Genus 22. Sporangia solitary, sessile. Licea (p. 32). 1 6 BRITISH MYCETOZOA. Order III. — Tubulinace^e. Sporangium-wall membranous, without microscopic round granules. Genus 23. Sporangia tubular, compacted. Tubidina (p. 32). Order IV. — Reticulariace^e. Sporangia combined into an aethalium, their walls incomplete, perforated, or forming a spurious capillitium. Genus 24. Sporangia columnar. Dictydicethalium (p. 33). Genus 25. Sporangium-wall reduced to broad bands. Enteridium (p. t,^). Genus 26. Sporangium-walls laciniated. Rcticularia (p. ^^). Sub-cohort U.—CALONEM1NEA?. Capillitium present; a system of uniform threads. Order I. — Trichiace/E. Capillitium of free elaters, or an elastic network with spiral thickenings. Genus 27. Elaters free, spirals distinct. Trichia (p. 34). Genus 28. Elaters scanty, spirals nearly wanting. Oligonema (p. 35). Genus 29. Elaters combined into a web or network. Hemitrichia (p. 36). Order II. — Arcyriace^e. Capillitium a profuse network of threads (sometimes scanty in Peric/ia'na), thickened with cogs, halt rings, spines or warts. Genus 30. Sporangia stalked, sporangium-walls evanescent above. Arcyria (p. 37). Genus 31. Sporangia sessile, the walls single, persistent. Lacluwbolns (p. 38). Genus 32. Sporangia sessile, the walls double. Perichcena (p. 38). Order III. — Margaritace^e. Capillitium coiled, hairlike and solid, or straight and attached to the sporangium-wall. Genus ^. Capillitium profuse, coiled. Margarita (p. 39). Genus 34. Capillitium straight. Dianema (p. 39). Genus 35. Capillitium penicillate, spirally banded. Prototrichia (p. 40). Order IV. — Lycogalace^e. Sporangia forming an aethalium ; capillitium consisting of branched colourless tubes. Genus 36. Lycogala (p. 40). BRITISH MYCETOZOA. 17 MYCETOZOA. De Bary. [MYXOMYCETES. Wallroth.] SUB-CLASS I.-EXOSPORE.E. ORDER I.— CERATIOMYXACEjE. Genus i. CERATIOMYXA Schroe- ter. — Surface of sporophores mapped out into polyhedral areolae, from the centre of each of which arises a slender stalk bearing a single ellipsoid spore. i C. mucida Schroeter. — Sporophores white or pinkish-yellow, forming either simple or branching tufts, or, in the va- riety porioides, a network resembling the pores of a Polypoms. Spores white, ellipsoid, smooth, 10 X 6 to 13 X 7 ft, diam. Hab. On rotten logs. Fig. 9. Ceratiomyxa mucida Schroet. a. Clusters of sporophores. Twice natural size. b. Sporophore. Magnified 40 times. c. Four areolae of mature sporo- phore : one spore still at- tached to its stalk, and another free. Magnified 480 times. SUB-CLASS II.— ENDOSPOREjE. Cohort l.—AMAUROSPORALES. Sub-cohort 1.—CALCAR1NEAI. ORDER I.— PHYSARACE^E. Genus 2. BADHAMIA. Berkeley. — Sporangium-wall mem- branous, containing lime-granules; capil- litium a coarse network charged through- out with granules of lime ; spores clustered or free. 1. B. hyalina Berk. — Sporangia glo- bose or pyriform, usually sessile, 1 to i*S mm. diam., greyish-white. Capillitium of broad, branching, anastomosing bands, white. Spores dark purple-brown, ad- hering in clusters of 8 to 20, more strongly warted on the outer third, n to 13 /x diam. Hab. On fir logs, etc. 2. B. utricularis Berk. — Sporangia ovoid, subglobose, or lobed, 0-5 to 1 mm. diam., clustered, with 2 Badhamia utricularis Berk. rt. Cluster or sporangia. Mag- nified 3^ times. b. Fragment of capillitium and spore-cluster. Magnified 140 times. 1 8 BRITISH MYCETOZOA. [Badhamia. membranous yellow branching stalks, or sessile, cinereous, or iri- descent violet. Capillitium white. Spores bright brown, in loose clusters of 7 to 10, equally spinulose all over, 9 to 12 fa, diam. Hab. On old stumps, feeding on woody fungi. 3. B. nitens Berk. — Sporangia subglobose, crowded, sessile, 1 mm. diam., golden or greenish-yellow. Capillitium orange-yellow. Spores in close clusters of 6 to 10, purple-brown, coarsely warted on the outer third, 10 to 13 ix. diam. Hab. On rotten logs. 4. B. macrocarpa Rost. — Sporangia subglobose, sessile, or with firm stalks, gregarious, 0-5 to 1 mm. diam., white. Capillitium white. Spores free, dark purple-brown, minutely and closely spinulose, 11 to 15 /x diam. Hab. On logs. 5. B. panicea Rost. — Sporangia subglobose, sessile, crowded, 1 mm. diam., white. Capillitium white, with occasional narrow hyaline threads. Spores free, violet-brown, nearly smooth, 11 /i diam. Hab. On bark of felled elms, etc. 6. B. lilacina Rost. — Sporangia subglobose, sessile, crowded, o-5 mm. diam., pale, flesh-coloured. Capillitium pale, flesh-coloured. Spores free, dark purple-brown, rough, with prominent and confluent warts, ii to 13 ^ diam. Hab. On decayed stumps, bog moss, etc. 7. B. rubiginosa Rost. — Sporangia obovoid, stalked, gregarious, 0-5 mm. broad, rufous-brown, pale above, columella half the height of the sporangium. Capillitium pale rufous. Spores free, dark purplish-brown, usually rough, with prominent confluent warts, 11 to 13 ix. diam. Hab. In fir woods, on fallen brushwood, etc. Genus 3. PHYSARTJM Persoon.— Sporangium-wall membranous, with innate deposits of lime, either in clusters of minute granules or compacted and chalky. Capillitium a network of delicate threads, with vesicular expansions filled with lime (= lime-knots). bw.'h' !• P- leucopus Link. — Sporangia glo- Physarum nutans Pers. bose, gregarious, o'5 mm. diam., glaucous- Two sporangia. Magnified cinereous; stalk stout, chalk-white in 9 times. . '..... , . Capillitium threads, with section throughout. Capillitium white ; frTgemen0tS'01atttnCehesPor0ana- l™e-knots large. Spores violet-brown, gium-waii. Magnified no nearly smooth, 7 to 10 ix diam. times- Hab. On dead leaves, etc. Physarum.] BRITISH MYCETOZOA. 19 2. P. murinum Lister. — Sporangia subglobose, stalked or sessile, brown, 0-5 mm. diam. Stalk charged with lime throughout. Capil- litium with brown lime-knots. Spores violet-brown, nearly smooth, 8 to 10 jx diam. Hab. On dead wood, leaves, etc. Rare. 3. P. citrinum Schum. — Sporangia subglobose, gregarious, 0-4 to 07 mm. diam., yellow ; stalk stout, yellow, charged with lime throughout. Capillitium rigid; lime knots yellow. Spores violet- brown, almost smooth, 7 to 8 ti diam. Hab. On dead wood, moss, etc. 4. P. psittacinum Ditm. — Sporangia subglobose, gregarious, 0-5 mm. diam., purple or metallic green mottled with red. Stalk orange-red, translucent. Capillitium with bright orange lime-knots. Spores dull violet, nearly smooth, 7 to 8 /x diam. Hab. On old stumps. 5. P. viride Pers. — Sporangia subglobose, nodding, scattered, o'5 mm. diam., yellow, greenish, or orange. Stalk subulate, trans- lucent, containing refuse matter. Capillitium slender; lime-knots fusiform, orange. Spores violet-brown, nearly smooth, 7 to 10 yu diam. Hab. On rotten stumps, etc. Common. 6. P. nutans Pers. — Sporangia subglobose, erect or nodding, gregarious, 0-4 to 1 mm. diam., pale grey. Stalk subulate, straw- coloured or dark, containing refuse matter. Capillitium slender ; lime- knots small, white ; spores violet-brown, nearly smooth, 8 to n /x diam. Var. leucophaeum. Sporangia erect, stalked, or plasmodiocarps stalks stouter. Capillitium more rigid ; lime-knots larger. Hab. On dead wood. Common. 7. P. calidris Lister. — Sporangia globose, scattered, 0^5 mm. diam., white. Stalk red, translucent. Capillitium-threads slender ; lime-knots white ; irregular in shape and size. Spores pale brownish- violet, nearly smooth, 8 to 1 1 /*. diam. Hab. On dead leaves, etc. 8. P. compressum Alb. and Schw. — Sporangia subglobose or lobed, compressed ; stalked, sessile or plasmodiocarps, grey. Stalk dark or white, containing refuse matter. Capillitium-threads terete, flexuose ; lime-knots white, numerous. Spores dark purplish-brown, spinulose, 9 to 14 /x diam. Hab. Dead wood, bark, and leaves. A very variable species. 9. F. didermoides Rost. — Sporangia ovoid, erect, crowded, 05 mm. broad, white, diffused grey above. Stalk short, white, membranous. Capillitium flexuose; lime-knots numerous, rounded. Spores very dark purple-brown, nearly smooth, 10 to 13/4 diam. Hab. On dead wood, leaves, etc. 20 BRITISH MYCETOZOA. [Physarum. io. P. Crateriachea Lister. — Sporangia white, rugose; either ovoid, erect, seated on an ochraceous hypothallus which is often produced into a short stalk, or forming plasmodiocarps. Capillitium a rigid network of hyaline threads ; lime-knots confluent in the centre of the sporangium, and forming an elongate clavate pseudo- columella, sparsely distributed elsewhere. Spores purple-brown, spinulose, 8 /x diam. Hab. On rotting herbaceous stems. Rare. ir. P. cinereum Pers. — Sporangia sessile, subglobose, or plas- modiocarps, scattered or crowded, 0^3 to 0-5 mm. diam., pale-grey. Capillitium with numerous white lime-knots. Spores violet-brown, nearly smooth, 7 to 10 /x diam. Hab. On dead leaves, etc. 1 2. P. bivalve Pers. — Sporangia sessile, elongate, laterally com- pressed, frill-like, splitting longitudinally, white or buff. Capillitium of numerous white lime-knots connected by short hyaline threads. Spores violet-brown, spinulose, 8 to 10 yu. diam. Hab. On dead leaves, etc. 13. P. Diderma Rost. — Sporangia sessile, subglobose, or elon- gate, sometimes compressed, plasmodiocarps, cr6 mm. or more wide ; the white outer sporangium-wall peeling off and disclosing the purplish inner layer. Capillitium with numerous white lime- knots. Spores purplish-brown, spinulose, 10 to 12 /x diam. Hab. On dead leaves, etc. 14. P. COlltextum Pers. — Sporangia sessile, obovoid, or reniform, curved, crowded, 0-5 mm. diam., ochraceous, the wall densely calcareous. Capillitium of numerous branching white lime-knots with short connecting threads. Spores dark violet-brown, spinulose, 10 to 13 jx diam. Hab. On dead leaves, etc. 15. P. conglomeratum Rost. — This species resembles P. con- textutn in general appearance, but differs in the spores, which are pale violet-brown, nearly smooth, 8 to 10 /* diam. Hab. On dead leaves, etc. 16. P. virescens Ditm. — Sporangia sessile, irregularly ovoid, o-2 to o-3 mm. diam., much aggregated in confluent groups, rugose, yellowish-green. Capillitium delicate flexuose, lime-knots yellow. Spores pale violet-brown, nearly smooth, 6 to 9 11 diam. Van obscurum. Sporangia more scattered, smooth, olive-brown, often forming plasmodiocarps, o'5 mm. diam. Hab. On dead leaves, etc. 17. P. rubiginosum Fries. — Sporangia sessile, subglobose, o'5 mm. diam., orange or deep red. Capillitium with branching orange lime-knots. Spores pale violet-brown, nearly smooth, 8 to li /x diam. Hab. On dead wood and leaves. Rare. FUL1G0.] BRITISH MYCETOZOA 21 Genus 4. FULIGO Haller.— iEthalium anastomosing sporangia enclosed by a barren cortex. 1. F. septica Gmel. — jEthalium pul- vinate, from 2 mm. to 20 cm. broad, yellow, sometimes cinereous or reddish. Sporangium-walls within the asthalium containing scattered innate deposits of lime. Capillitium of hyaline threads with yellow or whitish lime-knots. Spores violet, nearly smooth, 6 to 10 ft. diam. Hab. On rotten wood, tan, etc. Common. consisting of interwoven Fig. 12. — Fuligo septica Gmel. a. jEthalium. One-third natural size. b. Capillitium threads with lime-knots and two spores. Magnified 120 times. Fig- *3- ClENKOWSKIA RETICULATA Rost. a. Part of branching plasmodio- carp. Magnified 4 times. b. Capillitium threads and part ol a perforated lime-plate. Magnified 140 times. Genus 5. ClENKOWSKIA Rosta- finski. — Sporangium-wall cartilaginous at the base. Capillitium a loose network of rigid threads, with many free, curved, sharp-pointed branchlets, connected with flat perforated calcareous plates attached at their margins to the sporangium-wall. C. reticulata Rost. — Plasmodiocarps cylindrical winding, 0.5 mm. diam., usually anastomosing and forming a net, yellow- brown, blotched with crimson. Capilli- tium-threads yellow, the calcareous plates pale yellow. Spores violet-brown, mi- nutely spinulose, 9 to 11 /x diam. Hab. On dead wood. Rare. Genus 6. CRATERIUM Trentepohl. — Sporangia stalked, goblet-shaped or ovoid, usually dehiscing with a distinct lid ; sporangium - wall charged with granules of lime, cartilaginous in the lower part, thinner above. Capillitium containing large lime-knots usually con- fluent in the centre of the sporangium as a pseudo-columella. 1. C. pedunculatum Trent. — Sporan- gia smooth, goblet-shaped, with a pale lid. Capillitium with many large white lime-knots. Spores violet-brown, nearly smooth, 8 to 9 /x diam. Hab. On dead leaves. Common. 2. C. leucocephalum Ditm. — Sporangia top-shaped or ovoid, stalked, red-brown, white and mealy, with sprinkled yellow granules Fig. 14- Craterium pedunculatum Trent. a. Two sporangia ; in one the lid has fallen away. Mag- nified 10 times. b. Capillitium with lime-knots and two spores. Magnified no times. 22 BRITISH MYCETOZOA. [Craterium. on the upper half and lid. Capillitium with large white or yellowish lime-knots. Spores violet-brown, spinulose, 7 to 9 p diam. Hab. On dead leaves. 3. C. mutabile Fr.— Sporangia ovoid, stalked, without a distinct lid, rough, yellow, the wall thin, with innate clusters of yellow lime granules. Capillitium with pale yellow lime-knots. Spores violet- brown, spinulose, 8 to 9 ju. diam. Hab. On dead leaves. Genus 7. LEOCAEPUS Link.— Spo- rangium-wall uniform, of two layers; the outer cartilaginous and calcareous, shining; the inner hyaline. Capillitium of two systems, one a network of hyaline threads, the other of coarse anastomosing branches charged with brownish lime-granules. 1. L. verrucosus Link. — Sporangia ellipsoid, crowded, chestnut-brown, shining as if varnished, with short membranous stalks. Capillitium as in the genus. Spores violet-brown, 11 to 13 /u diam. Hab. On dead leaves, etc. Leocarpus vermcosus Link. a. Cluster of sporangia. Mag- nified 2^ times. b. Hyaline "threads and branch- ing lime-knot of the capil- litium, with two spores. Magnified 120 times. Gexus 8. CHONDRIODERMA Rosta- finski. — Sporangium-wall of two layers, containing granular deposits of lime. Capillitium without lime-knots. Sub - genus 1. Euchondriodcrma. — Sporangia mostly sessile, the outer wall a smooth crust composed of globular lime- granules, the inner membranous. 1. C. spuniarioid.es Rost. — Sporangia subglobose, sessile, crowded on a profuse hypothallus, white ; the two layers of the wall usually adhering. Columella convex, pale. Capillitium of slender flexuose purplish threads. Spores violet-brown, minutely spinulose, 8 to 11 /» diam. Hab. On dead leaves, etc. 2. C. globosum Rost. — Differs from C. spumarioides in the outer layer of the sporangium-wall separating more freely from the inner, and in the larger, darker, more spinulose spores, 10 to 14 p diam. Hab. On dead leaves, etc. 3. C. testaceum Rost. — Sporangia subglobose, sessile on a broad base, dull or pale flesh-coloured ; the eggshell-like outer wall of the Fig. 16. CHONDRIODERMA TESTACEUM Rost. a. Group of three sporangia ; in the upper one the double wall is broken away in part and the columella exposed. Magnified 9 times. b. Portion of the outer and inner layers of the sporan- gium-wall j to the latter the capillitium threads are attached : three spores. Magnified 170 times. Chondrioderma.] BRITISH MYCETOZOA. 23 sporangium separating from the inner. Columella large, hemi- spherical, reddish-brown. Capillitium as in the last species. Spores pale violet-brown, nearly smooth, 7 to 8 /a diam. Hab. On dead leaves, etc. 4. C. Michelii Rost. — Sporangia disc-shaped, on a stout, pale, ochraceous, central stalk, rarely sessile, chalk-white. Columella indefinite. Capillitium and spores as in C. tcstaccum. Hab. On dead leaves, etc. 5. C. reticulatum Rost.— Differs from C. Michelii in the shape of the sporangia only, which are flat plasmodiocarps, often branching and forming a net. Hab. On dead leaves, etc. 6. C. niveum Rost. — Sporangia subglobose, or plasmodiocarps, white ; the outer layer of the sporangium-wall thick, the inner membranous. Columella broad, convex, orange. Capillitium dark, somewhat rigid, warted. Spores violet-brown, minutely spinulose, 9 to 11 jx diam. Hab. On dead leaves, etc. Sub-genus 2. Leangium. — Sporangia mostly stalked ; sporan- gium-wall often dehiscing in revolute lobes; of two inseparable layers, the outer cartilaginous, charged with minute granules of lime, the inner membranous. 7. C. Trevelyani Rost. — Sporangia roundly ovoid, stalked or sessile ; chestnut-brown. The sporangium-wall differs from that in all other species of the sub-cohort Calcarinca; in being constructed of an outer, cartilaginous brown layer, a thick middle layer consisting of white crystalline calcareous deposits, and a delicate membranous inner layer, to which the ends of the capillitium are attached. Columella none. Capillitium a network of purple threads, with dark thickenings at the nodes. Spores dark violet-brown, spinulose, 10 to 12 /a diam. Hab. On dead leaves, etc. 8. C. Sauteri Rost. — Sporangia subglobose, depressed, sessile, pale pinkish-brown ; outer layer of sporangium-wall cartilaginous, brittle, separating from the membranous inner layer. Columella indistinct. Capillitium of sparingly branched, colourless or violet threads, 2 to 3 ju. diam. Spores dark violet-brown, spinulose, 10 to 13 fj. diam. Hab. On dead wood, moss, etc. Rare. 9. C. radiatum Rost. Sporangia subglobose, umbilicate beneath, usually with a short, stout stalk, pale grey or brownish ; sporan- gium-wall cartilaginous, obscurely granular, with an inseparable membranous inner layer. Columella hemispherical. Capillitium violet-brown, rigid, sparingly branched ; spores dark violet-brown, minutely spinulose, 9 to 12 /x diam. Hab. On bark, twigs, etc. 24 BRITISH MYCETOZOA. [Chondrioderma. io. C. floriforme Rost. — Sporangia globose, white or cinnamon ; sporangium-wall dehiscing on drying in revolute lobes. Stalks longer than in the last species. Columella ovoid. Capillitium of slender violet-brown threads with bead-like thickenings. Spores red-violet-brown, with widely scattered obtuse warts, 9 to 1 1 /x diam. Hab. On oak stumps, etc. 11. C. lucidum Cooke. — Sporangia subglobose, brown, shining; sporangium-wall of two layers, but without deposits of lime. Columella prominent, roundish, stalked. Capillitium of few, broad, branching, purplish-brown threads ; spores dark purple-brown, closely spinulose, 12 to 14 /a diam. Hab. On moss. Trefriw, N. Wales. A doubtful species. Fig. 17. DiacHjEA elegans Fries. Two sporangia, the one entire, the other deprived of the spores and showing capil- litium and columella. Mag- nified 22 times. Genus 9. DLA.CH.rEA Fries.— Lime not present either in the membranous sporangium-wall or in the network ot purple capillitium, but in the stalk and columella only. 1. D. elegans Fries. — Sporangia cylindrical, iridescent purple ; stalk white. Columella narrowing upwards, white, giving rise to the closely branching capillitium. Spores dull violet, nearly smooth, 7 to 9 fx, diam. Hab. On dead leaves. ORDER II.— DIDYMIACE.E. Genus 10. DIDYMIUM Schrader, sessile ; lime-crystals either scattered on the membranous sporangium-wall, or closely combined and forming a crust ; capillitium often thickened at intervals with dark nodes. 1. D. difforme Duby. — Sporangia hemispherical, on a broad yellowish base, or plasmodiocarps, white ; lime-crystals minute, densely' combined to form a smooth, eggshell-like crust, often separating from the iridescent inner sporangium-wall. Columella none. Capillitium scanty, the threads broad at the base, branched above. Spores dark purple-brown, nearly smooth, 11 to 14(1 diam. Hab. On dead leaves. Common. . — Sporangia stalked or Fig. DlDYHIUM EFFUSUM Link. r. Two sporangia, one entire, the other showingcolumella and capillitium. Magnified 12 times. >. Capillitium and fragment ot sporangium-wall, with crys- tals ol calcium carbonate and two spores. Magnified 200 times. Didymium.] BRITISH MYCETOZOA. 25 2. D. dubium Rost. — Sporangia thin, flat, roundish, white; lime-crystals stellate, adhering to form a frosted crust often extending beyond the margin of the broad membranous base of the sporangium. Columella none. Capillitium profuse, of rigid purple-brown, erect anastomosing threads, slender above and below. Spores violet-grey, nearly smooth, 8 to 15/1 diam. Hab. On dead leaves. 3. D. Serpula Fr. — Sporangia thin, effused, grey plasmodiocarps. Columella none. Capillitium of slender threads connected with large scattered purplish vesicles, 20 to 50 //. diam., filled with yellowish granular matter. Spores pale violet-brown, nearly smooth, 7 to 9 fi diam. Hab. On dead leaves, etc. 4. D. Clavus Rost. — Sporangia disc-like, grey, on a darker central stalk ; in shape resembling a flat-headed nail. Columella none. Capillitium profuse. Spores pale violet-brown, almost smooth, 6 to 8 fj. diam. Hab. On dead leaves. 5. D. farinaceum Schrad. — Sporangia hemispherical, deeply umbilicate beneath, grey; sporangium-wall mottled with brown. Stalk and broad columella dark opaque-brown. Capillitium of coarse pale or dark threads. Spores dark purplish-grey, nearly smooth, 9 to 1 1 jjl diam. Var. minus is smaller, with short stalks and slender capil- litium ; spores 7 to 9 //. diam. Hab. On dead leaves, bark, etc. 6. L. nigripes Fr. — Distinguished from D. farinaceum, var. minus, in the stalk being longer and more slender, and in being horn-clear instead of opaque and granular. Var. xanthopus Fr. has an orange stalk and white columella. Hab. On dead leaves. 7. D. effusum Link. — Sporangia very various, subglobose, hemispherical, stalked, sessile, or effused plasmodiocarps, white or grey; the stellate crystals adhering to form a wrinkled crust, or scattered ; stalk short, white, opaque, sometimes orange. Columella white. Capillitium colourless or dark. Spores violet-brown, spinulose, 8 to 1 1 /x diam. Hab. On dead leaves. 8. D crustaceum Fr. — Distinguished from D. effusum by the sporangia being often clustered and reniform, and by their being enclosed in a thick, smooth, fragile, globose crust of loosely adhering large crystals, and in the more strongly spinulose spores, 10 to 13 //. diam. Hab. On dead leaves, etc. 26 BRITISH MYCETOZOA. [Spumaria. Genus ii. SPUMARIA Persoon. — Sporangia confluent, forming an aethalium enclosed in a mass of white lime-crystals ; the other characters as in Didymium. i. S. alba DC. — Sporangia elongate and lobed, usually pene- trated by a hollow columella. Capillitium much branched. Spores dull purple, strongly spinulose, 10 to 13 /x diam. Hab. On grass, dead leaves, etc. Spumaria alba DC. a. JEthalium. Natural size. b. Capillitium and fragment 01 sporangium-wall, with crys- tals of calcium carbonate and two spores. Magnified 200 times. Fig. 20. Lefidoderma tigrinum Rost. a. Sporangium. Magnified 6 times. b. Capillitium and spores. Mag- nified 140 times. Genus 12. LEPIDODERMA de Bary. — Sporangium-wall carti- laginous, beset with superficial crystalline discs or scales. Capillitium usually rigid. 1. L. tigrinum Rost. — Sporangia subglobose, flattened beneath, dull olive, crystalline discs white. Stalk and hemispherical colu- mella dull orange. Capillitium threads purple. Spores dark purplish-grey, minutely spinulose, 8 to 13 ft diam. Hab. On bark, etc. Sub-cohort U.—AMA UROCHAZTINEAZ. ORDER I.— STEMONITACE.E. Stemonitis splendens Rost «. Group of sporangia. Natural size. b. Portion of capillitium and columella. Magnified 42 times. Genus 13. STEMONITIS Gleditsch.— Sporangia cylindrical, stipitate, fasciculate; stalk continued as a columella to near the apex of the sporangium. Capillitium radiating from all parts of the columella, the ultimate branches normally uniting to form a superficial net. 1. S. fusca Roth. — Sporangia dark or reddish-brown, 4 to 15 mm. high. Super- ficial net of the capillitium with angular meshes varying in size from less than to three times the width of the spore. Stemonitis.] BRITISH MYCETOZOA. 27 Spores grey, or rufous-violet, closely reticulate and spinulose, 6 to 10 fj, diam. Var. confluelis is an asthalioid form without superficial net or columella;. Hab. On dead wood. Common. 2. S. splendens Rost. — Distinguished from S.fusca by the large rounded meshes of the capillitium net, from three to fifteen times the width of the spores, and by the almost smooth, reddish-purple spores, 7 to 9 p diam., which, when magnified 1200 times, are seen to be minutely and closely warted. Var. flaccida has slender, weak stalks, and the meshes of the net very wide and broken. Hab. On dead wood. 3. S. ferruginea Ehrenb. — Sporangia cinnamon-brown, 5 to 7 mm. high. Meshes of the capillitium net as in S. fusca, but the threads more slender. Spores pale ferruginous, nearly smooth, 8 to 9 fi. diam. Plasmodium yellow. Hab. On dead wood. 4. S. Smitbii Macbr. — Distinguished from S. ferruginea by the longer sporangia and minute spores, 4 to 6 /x diam. Plasmodium white. Hab. On dead wood. Genus 14. COMATRICHA Preuss.— Sporangia subglobose or cylindrical, stalked, gregarious. Capillitium as in Stemonitis, except that it is more dense, and the ultimate branches do not unite to form a superficial net. 1. C. obtusata Preuss. — Sporangia globose, ellipsoid, or cylindrical, purple- brown. Total height, 1 to 6 mm. Stalks Fig. 22. slender. Capillitium a dense tangle of Comatricha obtusata Preuss. purplish-brown threads; ultimate branches a. Group of sporangia. Natural usually looped. Spores brownish-violet, b sporangium deprived of nearly smooth, 7 to 1 1 u. diam. fp?'" s.>}owiPg >hS. t?aPjl- i_ , „ ',' , r, „ htium. Magnified 16 times. Hab. On dead wood. Common. 2. C. laxa Rost. — Distinguished from C. obtusata by the lax capillitium, and by the branches spreading from the columella in a more straight and radiating direction. Hab. On dead wood. 3. C. lurida Lister. — Sporangia globose, purple-brown. Stalk setaceous, 075 mm. long. The purple-brown flexuose capillitium spreads from the upper half of the branching columella, which reaches to half the height of the sporangium. Spores purplish-grey, warted, 8 to 10 /a diam. Hab. On dead leaves. Hitherto only found at Lyme Regis. 28 BRITISH MYCETOZOA. [COMATRICHA. 4. C. typhoides Rost. — Sporangia shortly cylindrical, brown after the disappearance of the silvery evanescent sporangium-wall. Columella reaching to near the apex of the sporangium. Capillitium a close network of pale-brown flexuose threads with many free ends. Spores pale violet-brown, almost smooth, 4 to 7 /x diam. Hab. On rotten wood. 5. C. Persoonii Rost. — Sporangia cylindrical or clavate, rufous- brown, including the stalk about 1 mm. high; columella nearly reaching the apex. Capillitium dense, of flexuose brown threads, the ultimate branches looped, with few free ends. Spores pale lilac- brown, minutely warted, 6 to 8 fn. diam. Hab. On dead leaves. 6. C. rubens Lister. — Sporangia subglobose or pyriform, pinkish- brown, including the stalk about 1*5 mm. high. Columella branched above, and reaching two-thirds the height of the sporangium. Capillitium brownish-violet, branching from all parts of the colu- mella, with slender free ends. The lower branches have broad attachments to the lower part of the sporangium-wall, which forms a persistent cup. Spores as in C. Persoonii. Hab. On dead leaves. Genus 15. ENERTHENEMA Bowman.— Sporangia stipitate ; columella reaching to the summit of the sporangium. Capillitium springing from beneath the superficially extended apex of the columella. 1. E. elegans Bowm.— Sporangia globose, black. Capillitium threads long, sparingly branched. Spores greyish-brown, spinulose, S to 10 fj. diam. Hab. On dead wood. Fig. 23. Enerthenema elegans Bowm. a. Group ol' sporangia. Twice the natural size. b. Sporangium. Magnified 16 times. c. Sporangium deprived of spores, showing the capil- litium. Magnified 16 times. Fig. 24. Lamproderma irideum Mass. a. Group of sporangia. Magni- fied 2j times. b. Sporangium deprived ot spores, showing capillitium. Magnified 25 times. Genus 16. LAMPRODERMA Rostafinski.— Sporangia globose or ellipsoid, stipitate; sporangium-wall somewhat persistent, shining Lamproderma.] BRITISH MYCETOZOA. 29 with iridescent colours. Capillitium of branching and anastomosing threads radiating from the upper part of the columella. 1. L. physaroides Rost. — Height of sporangium with the stalk 2 to 3 mm. ; sporangium ovoid or globose. Columella subclavate, reaching to more than halt the height of the sporangium. Capil- litium of purple-brown threads, straight and sparingly branched below, springing from the upper half of the columella. Spores purple-grey, closely spinulose, n to 14 li diam. A sessile form occurs without a columella. Hab. On fir wood. 2. L. echinulatum Rost. — Total height 2 to 2-5 mm. Sporangia globose. Columella cylindrical, obtuse, half the height of the sporangium. Capillitium lax ; of nearly straight, sparingly forked, black, strong threads with pale tips, springing from the upper part of the columella. Spores dark grey, echinulate with black spines, 15 to 20 ft diam. Hab. On dead wood. 3. L. arcyrionema Rost. — Total height 1 to 1-5 mm. Sporangia globose, 0-5 mm. diam. Columella half the height of the sporangium, slender, smooth to the apex, where it divides into the primary branches of the black, crisped capillitium. Spores lilac-grey, smooth, 6 to 7 fx. diam. ' Hab. On dead wood. 4. L. irideum Mass. — Total height 1 to 1*5 mm. Sporangia globose, on setaceous stalks. Columella cylindrical, half the height of the sporangium. Capillitium of rigid, dichotomously-branched, blackish threads, which are colourless at the base, where they are attached to the truncate apex of the columella. Spores marked with minute, not crowded warts, 6-5 to 8 /x diam. Hab. On dead leaves. Common. 5. L. violaceum Rost. — Total height, o-6 to 1*5 mm. Sporangia subglobose on setaceous or thicker stalks. Columella one-third to two-thirds the height of the sporangium. Capillitium white and flaccid, or brown and dense. Spores purplish-grey or purple-brown, closely spinulose, 8 to 11 11 diam. Var. Sauteri is a robust form ; stalks thickened below ; capil- litium brown; spores 11 to 15 ti diam. Hab. On sticks, dead leaves, etc. A variable species, sometimes resembling forms of L. irideum, but distinguished by the spores. These, when highly magnified, are seen to be marked with closely set, often very minute spines, and not with the more distant warts characteristic of that species. 30 BRITISH MYCETOZOA. [Amauroch.ete. ORDER II.— AMAUROCHzETACEzE. Genus 17. AMAUROCHzETE Rostafinski. — zEthalia pulvinate, composed of elongate confluent sporangia ; sporangium-walls not developed ; capil- litium rising from the base in irregularly flattened and ragged strands, rarely form- ing a more regular network. 1. A. atra Rost.— zEthalium black, covered with a silvery evanescent mem- brane. Capillitium black, often very scanty. Spores dull purple, spinulose, 11 to 13 /» diam. Hab. On fir wood. Amauroch^ete atra Rost. zi. zEthalium. Half natural size b. Capillitium. Magnified ic imes. Genus 18. BREFELDIA Rostafinski.— zEthalia pulvinate, com- posed of subcylindrical, branched, and confluent sporangia. Capillitium of nume- rous horizontal threads, those of adjacent sporangia uniting on the boundary line and there forming a many-chambered vesicle. 1. B. maxima Rost. — zEthalia some- times many inches across, purplish-brown. Capillitium brown. Spores purplish- Fig. 26. brown, minutely spinulose, 9 to 12 /a Brefeldia maxima Rost. diam. rt. zEthalium. Natural size. Hab. On dead wood. *• °}gM«g- jo ^ »P»» Cohort U.—LAMPROSPORALES. Sub-cohort 1.—ANEMINE&. ORDER I.— HETERODERMACEzE. Genus 19. LINDBLADIA Fries. — Sporangia either combined to form an aethalium or closely compacted on a strongly-developed hypothallus. 1. L. Tubulina Fries. — zEthalia thin or pulvinate, formed of confluent sporangia with persistent membranous walls; either black and rugose, with a cortex of imper- fectly developed spores, or umber-brown with a surface of unbroken sporangia. Spores ochraceous-brown, nearly smooth, Linddlvdia Tubulina Fries. 4 to 6 /u. diam. s. 6cl. ■ Seals and Whales. Second edition. 101 Woodcuts. 1866, 8vo. 8s. Supplement. 11 Woodcuts. 1871, Svo. 2s. 6d. List of the Specimens of Cetacea in the Zoological Department. 18S5, Svo. is. 6d. Cataloaue of Ruminant Mammalia (Pecora, Linnseus). 4 Plates. 1872, Svo. 3.1. 61I. Marsupialia and Monotremata. 2S Plates (4 col). 188S, Svo. Birds. Catalogue of the Birds. Vols. VI.-XXIII. and XXVII. 1881-95, Svo. Wood- cuts and coloured Plates. 14*. to 36^. a volume. (Vols. I.-V. out of print.) --Reptiles and Batrachians. Catalogue of Chelonians, Rhynchocephalians, and Crocodiles. 73 Woodcuts and 6 Plates. 1889, 8vo. 15.1. Lizards. Second edition. Plates. 3 Vols. 1885-87, 8vo. Vols. I., II., 2OJ. each ; III., 26s. Snakes. Vol. I. 26 Woodcuts and 28 Plates. 1893, 8vo. 2U. Vol. II., 25 Woodcuts and 20 Plates. 1S94, Svo. 17^. 6J. Batrachia Salientia. 12 Plates. 185S, Svo. 6s. Batrachia Gradientia s. Caudata, and Batrachia Apoda. Second edition. 9 Plates. 1SS2, 8vo. 9-f. Fishes. Catalogue of Fishes. Second edition. Vol. I. Woodcuts and 15 Plates. 1895, 8vo. 1 5 s. Lophobranchiate Fish. 4 Plates. 1856, i2mo. is. Spiders. Descriptive Catalogue of the Spiders of Burma. 1895, Svo. los- &'• Lepidopterons Insects. Illustrations of Typical Specimens of Lepidoptera Heterocera. Parts III., V.-IX. Coloured Plates. 1879-93, 4t0- £2 to £2 l0s- a Part- (Parts L, II., and IV. out of print.) Corals. Catalogue of the Madreporarian Corals. Vol. I., 35 Plates. 1893, 4to. 245. British Animals. Catalogue of British Hymenoptera. Second edition. Parti. New issue. 1891, 8vo. 6s. British Echinoderms. Woodcuts and 16 Plates. 1S92, Svo. 12s. 6rf. Botany. A Monograph of Lichens found in Britain. Parti. 74 Woodcuts. 1S94, 8vo. 16s. of the Mycetozoa. 78 Plates and 51 Woodcuts. 1894, 8vo. 15s. Palaeontology. Catalogue of Fossil Mammalia. Parts I.- V. Woodcuts. 18S5-S7. 8vo. 4s. to 6s a volume. Fossil Birds. 75 Woodcuts. 1891, Svo. 10s. 6d. Fossil Reptilia and Amphibia. Parts I. -IV. Woodcuts. 18S8-00, Svo. ys. 6d. a volume. ■ Fossil Fishes. Parts I— III. Woodcuts and Plates. 1SS9-95, Svo, 2\s. a Part. Fossil Cephalopoda. Parts I., II. Woodcuts. 1S8S-91, 8vo. Part I.. 10.-. 6./.; II., \$s. Systematic List of the Edwards Collection of British Oligocene and Eocene Mollusca. 1 89 1, Svo. 6/. Catalogue of British Fossil Crustacea. 1877, Svo. $s. Blastoidea. 20 Plates. 18S6, 4to. 25*. Fossil Foraminifera. 1882. Svo. $s. Palaeozoic Plants. 1S86, Svo. 5-f. ■ Mesozoic Plants. The Wealden Flora. Woodcuts and Plates. Part I. 1894, 8vo, 10s. ; Part II. 1895, 8vo, 15s. The Catalogues can be purchased of Messrs. Longmans & Co., 39. Paternoster Row; Mr. Quaritch, 15, Piccadilly; Messrs. Kegan Paul, Trench, Trubner, & Co., Paternoster House, Charing Cross Road; and Messrs. Dulau & Co., 37, So/10 Square ; or at the Natural History Museum, Cromwell Road, London, S. IV. A more detailed list can be obtained on application to The Director of the Museum. GUIDE-BOOKS. A General Guide to the British Museum (Natural History). With 2 Plans and 2 Views. Svo. 31/. Zoological Department. Guide to the Galleries of Mammalia. 57 Woodcuts and 2 Plans. Svo. 6d. Galleries of Reptilesand Fishes. 101 Woodcuts and 1 Plan. Svo. 6d. Shell and Star-fish Galleries. 51 Woodcuts and 1 Plan. 8vo. 41/. [Guides to other sections are in preparation.] Geological Department. A Guide to Department of Geology and Paleontology : — Part I. Fossil Mammals and Birds. 119 Woodcuts and 1 Plan. 8vo. 6d. Part II. Fossil Reptiles, Fishes, and Invertebrates, 94 Woodcuts and 1 Plan. 8vo. 6a. Guide to the Fossil Fishes. 81 Woodcuts. Svo. 4» JT *J )) 7» *J )» J» 5.30 Also, from May 1st to the middle of July, on Mondays and Sal unlays only, till 8 p.m., and from the middle of July to the end of August, on Mondays and Saturdays only, till 7 P.M. 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