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The Uredineae, or rusts, constitute one of the most important groups of parasitic fungi, and their ravages are known wherever plants are cultivated. The cereals and grasses of our fields, the fruit trees of our orchards, even the ornamental plants of our gardens, and many of our forest trees are attacked by members of this family, and their study is not only interesting from the point of view of the scientist, but from that of every grower of plants for pleasure or for profit. Rusts are usually so conspicuous that they attract the attention of even the ardinary observer, and they have been known and recognised even from the earliest times, particularly from their blighting effects on the wheat and corn crops. Although so long known as regards their naked-eye characters, and the effects they produce, their structure and life-history have only been understood within comparatively recent times, and even now there are many points concerning them which await investigation. Their structure essentially consists of an inconspicuous my celium bearing the usually conspicuous spores, and while this vegetative mycelium is generally similar throughout the group, the spores produced by it are very dissimilar. The general study of this group will therefore mainly resolve itself into a knowledge of the different spore forms, and their relation to each other, either on the same plant or on different plants. The finishing spore or ¢elewtospore may be regarded as the ultimate stage of the Uredineae, and which, after usually resting for a period, long or short, germinates by putting forth a germ-tube, which bears, in turn, another kind of spore. The germ-tube is known as the pro-mycelium, and the spore as the promycelial spore, or sporidiolum, so that if the latter is regarded as the starting point, the teleutospore will constitute the finish. Between these two forms there may be various intermediate stages, and the series may consist of the following :— 1. The sforidiolum, when it produces its germ-tube, enters the tissues of the host-plant, and may either produce from its mycelium felewtospores similar ‘to those from which it originated ; or 2. It may give rise to uredospores at first, and subsequently teleutospore ; OY 3. It may produce aecidiospores, uredospores, and teleutospores in succession, the aecidiospores being generally preceded or accompanied by a peculiar form of spore, known as a spermatium. Hence the complete series of spore-forms will be spermatium, aecidiospore, uredospore, teleutospore, and sporidiolum, although between the initial sporidiolum and the final teleutospore, one or more of the above may be suppressed or omitted in the life-cycle. 2 Introduction. This succession of spore-forms may be represented graphically by the following diagrams :— Sporidiolum Sporidiolum * Teleutospore Aecidiospore Teleutospore Aecidiospore Uredospore Fig. 1. Fig. 2. Sporidiolum Sporidiolum . Teleutospore ss Uredospore Teleutospore Fig. 3. Fic. 4. The first shows the complete cycle of development in which all the sporé-forms follow each other in invariable order, and this is the most common form. In the second the uredospore is suppressed, and the number of species undergoing this contracted cycle is much reduced. In the third the aecidiospore is wanting, and the number of forms is still further reduced. And in the fourth the cycle of development is reduced to its lowest limits, a direct succession of teleutospores occurs, and the number of species, instead of reaching a minimum, probably ranks next to those with a complete development. The spermatia succeed the sporidiola, and are generally present in the life-cycle, but they do not enter into the general development. Besides these regular forms, there are others which are generally re- garded as representing either stages in the life-history of imperfectly known species or degraded forms of whick only the uredospores or aecidiospores are known. The subject, therefore, naturally divides itself into a consideration of the vegetative organs or mycelium and the various reproductive bodies or spores enumerated above, together with the structures accompanying them. The life-history of each form, as far as known, will be briefly sketched ; but this has still to be investigated in most of the recorded species. Vegetative Organs. 3 CHAPTER IT. VEGETATIVE ORGANS—MYCELIUM. The vegetative portion of many fungi is very inconspicuvus as com- pared with the reproductive, but its importance is not to be measured by its size or extent, rather by the part it plavs in the life of the organism ; and since it is the foundation of the whole, it is worthy of the most careful study. Of late years, however, this part has come into special prominence, particularly in the case of the cereal rusts, for it has been asserted that it is not always by external infection that the rust begins its career in the growing plant, but that in some cases it originates from within, and this theory; will engage our attention later on. Meanwhile this is referred to to show that the key to the propagation of the rusts from year to year may be not only on the surface, among the special reproductive bodies which spread it throughout the growing season, but also in the interior among the cells where the first beginnings of its life may appear. Among the recent investigations on the mycelium, there are two which stand out on account of their completeness. owing to the use of the most modern histological methods—the one by Professor Marshall Ward? on the Histology of Uredo dispersa Eriks, and the Mycoplasm hypothesis, and the other by Professor Eriksson on Das vegetative Leben der Getreiderost- pilze [The Vegetative Life of the Cereal Rusts]. The study of an indivi- dual case will prepare us for the more general examination of the mycelium throughout the rusts, and we will begin with that of Puccinia dispersa Eriks., or, strictly speaking, P. bromina Eriks., which Ward has so thoroughly dealt with and illustrated with such admirable clearness. Starting with the germination of the uredospore on the surface of the leaf, which usually occurs within twenty-four hours, we find that the young germ-tube grows rapidly, and that the nucleus of the spore passes into it ; sometimes, however, two or more nuclei may appear in it. ‘The tip of the tube begins to swell over a breathing pore or stoma into a thin vesicle, and the contents derived from the spore accumulate here. This external vesicle or appressorium, as it is called, is the first stage in inoculation from the outside, for a thin process is passed through the opening of the stoma, and swells inside into another vesicle. ©The proto- plasmic contents are transferred from the external to the internal vesicle, and so the future growth takes place among the tissues of the leaf. At one or more points this inner swelling forms a delicate tube, into which the protoplasm is again transferred, and its nucleus soon divides. This is the first-formed yfha, and the foundation of the vegetative system. It soon branches and develops cross partitions or sega, and extends rapidly among the cells of the host-plant to form the mycelium. Even at an early stage, when the primary hypha is still unbranched and unseptate, suckers or haustoria may be formed to provide a large imbibing surface for the fungus. The haustorium begins as a small delicate process or projection from the hypha, and this pierces the cell-wall and swells up into a minute spherical head, which is provided with a nucleus. Shortly after entering the cell this head takes on an irregular growth, and may assume a variety of shapes. The mycelium now becomes denser towards the surface, and prepares for the production of the reproductive bodies or spores. This constitutes the history of the mycelium from the time it starts as a germ-tube until it reaches its full development. 4 Vegetative Organs. Eriksson has investigated on similar lines, and fully illustrated the mycelium of Puccima glumarum, Eriks. and Henn., but with this important difference that instead of starting with external infection from a spore, he begins with an assumed internal germ of disease, which he considers in certain cases to be a source of rust, in addition to the ordinary infection by spores. It is often stated that this rust passes the winter as mycelium in such leaves as are attacked in late autumn, and which persists till the following spring; but the examination of hundreds of sections of leaves taken from rusty plants, although not rusty at the place chosen for section, failed to reveal the presence of such a mycelium dormant in the tissues. It may be taken for zranted, then, that there is no mycelium to start with, and it will be interesting to follow Eriksson’s theory as to the manner in which the mycelium arises afresh in the tissues. In certain cells of the autumn and spring leaves a peculiar thick plasma is found, containing a distinct nucleus, and this Eriksson considers to be, not the ordinary pro- toplasm of the cell, but a mixture of it, with the earliest vegetative form of the fungus. This intimate mixture or symbiosis, or living together of the ordinary protoplasm of the host and that of the fungus he distinguishes as mycoplasm. ‘This mycoplasm is stated to occur only in certain cells. which favours the assumption that it is not a mecessary constituent of the cell. The next step and the youngest stage of mycelial formation, according to Eriksson, is the presence of a plasma in the intercellular spaces, which is partly in the form of growing filaments, partly as irregular masses. There are no septa, and no distinctly recognizable nucleus, and even a dis- tinct wall is not formed. The primary stage is quickly followed by a secondary stage, in which the only visible advance is a very distinct nucleus. These two stages are very sharply marked off from the normal mycelium, both by their plasmodia-like nature and the absence of transverse septa. and for distinction the special name of protomycelium is given. Eriksson has no doubt that the intracellular mycoplasm and _ the __inter- cellular protomycelium are genetically connected, but this, which is a necessary link in the chain of evidence, requires to be further investigated. (Note 1, p. 74.) The formation of haustoria is the next process, and consists in a small straight prolongation of the protomycelium passing into the interior of the cell, and at the apex forming a globular swelling, probably containing a nucleus. Soon the whole forms a sac-like irregular organ. which may become detached from the protomycelium. These detached bodies in the cell were mistaken by Eriksson for a preliminary stage in the formation of hyphae, and called ‘‘special corpuscles,’’ but Ward pointed out their true nature, and that they really had been formed by, instead of giving rise to the hyphae, a correction which Eriksson himself has acknowledged. The haustoria are often found closely adjoining the nucleus, which thereby degenerates, and simultaneously with the shrinking of the nucleus, and soon after the first entrance of the haustoria, trans- verse septa begin to be formed in the protomycelium. In most of the cells thus formed several nuclei are contained, and the stage is now reached where a true mycelium is present, composed of hyphae. This multiplication of the cells of the fungus is a sign of advancing maturity. By continued division a true pseudo-parenchyma is formed, and at certain spots, where the cells appear to be particularly rich in food- material, a kind of hymenium arises, from which ultimately the spores are detached. Where spores are being formed, there the complete destruc- tion of the cells of the host-plant occurs, and now the vegetative life of the fungus is ended, and the reproductive phase is entered upon. Vegetative Organs. 5 Perennial Mycelium.—lIn contrast to the localized mycelium, there may be a mycelium with unlimited growth which does not confine itself to par- ticular spots, but may permeate entire shoots, or even the whole plant. This is known as a perennial mycelium, and wherever it occurs the fungus may reappear on the same plant year after year without the necessity for reinfection by means of spores. This vegetative reproduction through a perennial mycelium is not always easy to prove, but its importance cannot be overrated, for hidden in the tissues of the plant it cannot be reached by the ordinary means for con- trolling the growth and spread of fungi, but involves the destruction of the plant, or at least of those parts which harbour it. As Australian ex- amples, we may note Uromyces trifolii, which attacks the white clover (Trifolium repens) and Phragmidium subcorticium or rose-rust, in which the mycelium of the aecidial stage penetrates all the tissues, and in each succeeding year forms a mew layer beneath the old. Uromycladium notabile and U. tepperianum occurring on species of Acacia are further examples, for the mycelium gives rise to large galls, which persist from year to year and produce spores. Even although the host-plant is an annual, and dies down every year, it is still possible for the mycelium to be perennial, for it may be carried over winter in the seed, as in the case of Uromyces euphorbiae, according to Carleton %. Witches’-brooms.—It is not unusual among the forest trees and shrubs of Europe to find shoots very much deformed and distorted, and looking at a distance like large birds’ nests or brooms, and to these the popular name of witches’-brooms has been given. These peculiar and diseased conditions were difficult to account for, and so the idea may have originated with superstitious people that the trees were bewitched, in order that the witches might be provided with brooms for their midnight rides, hence the name. But the true cause is seen when the matter is investigated in the light of our present knowledge, and parasitic fungi are often found to be respon- sible for the strange transformations of the normal shoots into the dense twiggy, irregular tufts met with. This may also be produced by other means, such as gall-mites, but a very striking case and the first recorded instance in Australia is that of the rust-fungus, Crvonartium jacksoniae, which deforms the shoots of various leguminous plants as shown in Pls. XXXVII., XXXVIII. Uvromycladium tepperianunt also produces this peculiar appearance on Acacias as shown in Pl. XLII. The perennial mycelium in the shoots stimulates a number of buds to abnormal growth, quite different from the ordinary, and the result is seen in the numerous densely crowded and considerably altered shoots as com- pared with the normal. They are also thickly studded with the ruddy brown columns of teleutospores, in the case of Cronartium, which stand out like so many curved or straight, stiff bristles, towards the ends of the shoots, which are gradually being destroyed. Next year the mycelium will grow into the young shoots and produce the same result. Formation of Gails.—It is well known that the mycelium of fungi exer- cises a stimulating effect upon growth, and not only causes the cells to grow larger and divide more frequently than usual, and the chlorophyll to dis- appear, but it may alter the character of the tissues. When an insect pierces the young and living tissue of a plant with its proboscis or ovipositor, it often causes the cells immediately surrounding it to grow and divide more rapidly than elsewhere, so that a swelling of the tissue occurs, which is known as a gall. So among the rusts there are instances where the stimu- lation of growth occurs in a marked degree, and if a vegetable gall be 6 Vegetative Organs. considered as a morbid enlargement of the affected part of the plant, due to parasitic agency (Connold'), then there need be no hesitation in calling these structures galls. Perhaps the most striking illustration of a gall is seen in Uromy- cladium tepperianum. In the neighbourhood of Melbourne hedges of Kan- garoo Acacias (A. armata) are being gradually and completely destroyed by the ravages of this fungus, which resemble on a superficial view large galls caused by insects. Most of the branches, including the phyllodes, are infested with the chocolate-brown swellings, which may be in the form of a succession of small excrescences about the size of peas, or collected into large clumps about the size of walnuts, and measuring 4 cm. across. In some cases they are solid round knobs, and the external appearance is due to the dense covering of the chocolate-brown teleutospores. One of the lar- gest was met with at Myrniong on Acacia implexa of an irregular leg-of- mutton shape and weighing about 3 lb. (Pl. XLI). On A. pycnantha, or Golden Wattle, the galls are as large as potatoes, and in some of the wattle plantations, where the trees are cultivated for their bark, they hang in large numbers from the branches like so many fruits, and numbers of the trees are either dying or dead. The swellings are primarily caused by the fungus, and then various insect larvae tay ultimately invade them, boring and tunnelling through them. In A. zmplexa the swellings may run along the whole length of the elongated phyllodes, and in A. salicina there is an all-round swelling of the branches, and the periderm is ultimately ruptured. Magnus* found the galls to be per- meated by an intercellular mycelium, which was multiseptate with numerous and somewhat branched haustoria. Some very large galls were also found on the Black Wattle (A. decur- rens) and Silver Wattle (A. dealbata) either surrounding or terminating the branches, and caused by U. notabile. Some measured 4-5 inches across, and 3-4 inches was not uncommon, while one of the largest weighed 15 az. The peculiar gall-like swellings caused by Gymnosporangium may be mentioned, the mycelium of which is perennial in the various species of Juniper, and from their appearance are popularly known as “cedar apples ’’ in America. It may be an annual gall only bearing the teleuto- spores for one season, or a perennial gall, producing successive crops cf teleutospores year after year, and not requiring the transfer of the spores each season. Localized Mvycelinm.—The localized mycelium may lkewise produce conspicuous swellings, particularly on the stem and midrib of the leaves. Thus, that of Aecidium urticae causes hard curved thick swellings of con- siderable extent, and such a development of starch takes place in some Himalayan species of nettle attacked by this fungus that the natives eat the overgrown and hypertrophied stems for food. In other cases the affected tissues may be so stimulated by the localized mycelium as to cause their death. Thus almond leaves have been found here badiy riddled with “shot-hole,’’ due to the mycelium of Puccinia pruni Pers, just as P. malvacearum may also destroy a circumscribed area which becomes separated around its circumference, and falls out, leaving a circular hole. The mycelium, whether localized or perennial, is always beneath the surface of the plant, and formed within the living tissues. It is delicate in texture, like all internal mycelia, and branches to form a regular net- work, ultimately forming compact cushions or spore-beds. It can often be traced from a single point of infection, whence it radiates all round and spreads, gathering material for the fresh production of spores. Reproductive Organs. 7 CHAPTER LE. REPRODUCTIVE ORGANS—SPORES. A detailed account of the different spore-forms will be given in the sys- tematic part in connexion with the vairious species ; but it will be convenient here to take a preliminary view of some of the more essential general features, such as distribution, germination, and infection, suppression or omission, and repetition of spore-forms. DISTRIBUTION. The most important means of distribution of the rust-spores, as for fungus spores generally, is the wind. They are usually exposed on longer or shorter stalks, often powdery, and their immense numbers and lightness all render them easily detached, and spread by the slightest breath of wind. That the wind is an important factor in the distribution of rust-spores is strikingly shown in an example given by Halsted!. The asparagus rust (Puccinia asparagi, DC.) was very bad, but in one field the plants had been cut over, and the rusty brush removed in order that the new growth might escape. On examining this field about five weeks afterwards, he found that the rust showed only on one side of the green plants, and that was the side exposed to an old and very badly rusted asparagus bed. That this was the source of infection was obvious from the fact that a house with a few trees around it intercepted a portion of this field, and there was less rust upon that portion of the new bed in line with the house. The dust-storms which occur will also be a fruitful source of spreading them, and in our northern areas where the dust is sometimes carried in such quantities as to obliterate fences, it can easily be understood how even in virgin soil the spores of wheat rust may be found. The rain will also help to scatter them, particularly over individual plants, and on the surface of the soil, for it is a common observation how rusty plants are cleared after a heavy shower. Insects as well as other animals serve the same purpose. I have often observed the larvae of a species of Cecidomyia feeding on uredo and aecidio-spores, and at the same time spreading them while crawling along. Lindroth! has observed in Finland the occurrence of these larvae on no less than sixty-one species of rusts, and similar larvae have been found feed- ing on the conidia of various species of Ozdium (Salmon!). In some pot experiments with wheat, I found the larvae associated with the Oidium of /-. graminis, and feeding on the conidia. At first sight it might seem as if this devouring of the spores would tend to reduce the fungus, but the wholesale way in which the spores are carried about more than counter- balances any decrease from this cause. GERMINATION. As a rule, uredo and aecidio-spores germinate easily in a damp chamber, and I have found the method recommended by Plowright to be very con- venient. A gardener’s propagating glass is used, placed on a plate of water. and a simple stand is made with two flat oblong pieces of gutta- percha. Holes are easily bored in them. and glass rods placed parallel between them, so that the microscopic slides may be laid across the rods. 8 Reproductive Organs. The influence of various chemical substances on germination has been in- vestigated, and it has been found that some substances, such as solutions of sugar and nitrate solutions, hasten germination ; but for general purposes water alone is all that is necessary. Sometimes, however, the spores will germinate and infect the leaves of the host-plant, although they may not do so in water. Freeman! found this to be the case in dealing with the uredo-spores of Puccinia bromina, and concludes that the negative results in distilled water tests are not always an indication that the spores are incapable of germination. The temperature seems to exercise an important influence. Eriksson found that in many cases the spores germinated more freely if previously exposed to a temperature of o deg. C. or under, and Marshall Ward that the uredospores of P. bromina were not injured by being ex- posed’ to a temperature of — 5 deg. C. for ten minutes, while the same tem- perature continued for four to five hours killed them. Heat or cold, drought or damp, age and ripeness, are all factors of importance in germination. DuRATION OF GERMINATING POWER. How long do the spores retain their germinating power is an important question to settle ; but not many definite determinations have been made. De Bary states that the uredospores of P. graminis, kept dry, lose their germinating power in one to two months. Marshall Ward found that the uredospores of P. bromina preserved dry for sixty-one days retained their germinating power ; but it was feeble. Barclay found certain uredospores still capable of germination after from two to eight months, the leaves on which they occurred being kept dry. “It is a question of great scientific interest in connexion with rust in wheat if the uredospores can retain their germinating power during the winter. The results vary, as might be expected, according to the condi- tions prevailing at the time. In contrast to De Bary’s results, Eriksson found that the uredospores of VP. graminis lost their germinating power during the winter if kept in the open, but retained it if kept inside. Tlitchcock and Carleton!, however, collected fresh uredospores from growing plants of P. ruwbigo-vera at various times during the winter, and found them capable of germination. In our comparatively mild winters the uredospores retain their power of germination, and this seems to be the means whereby the fungus is continued from season to season. I have had freshly gathered uredospores of P. graminis from growing wheat and oats, and P. ?¢riticina from wheat germinating freely in water in winter (June to August). The uredospores can germinate at once, and directly infect the host-plant, or they can act as resting spores for a time, and freely infect the next season’s growth, under the climatic conditions which prevail here. The germination of teleutospores takes place at different periods, ac- cording to the nature of the species. They may either germinate imme- diately on reaching maturity, or, as is the case in the majority of heteroecious rusts, only after undergoing a period of rest—in the old world usually in the winter, but here, as no doubt sometimes elsewhere, the period of rest is often partly in the summer, when drought checks growth as effectively as the cold of a European winter. Eriksson” has shown that the teleutospores of P. graminis, with few exceptions, only germinate in the spring following their formation, and only then if kept in the open during the winter. He kept spores in the herbarium for one or two winters, and then on exposing them for another winter, he found that they germinated. but this was exceptional. Reproductive Organs. 9 In other species there is considerable variation. According to Woronin!, the teleutospores of P. helianthi germinated equally well when kept dry ina room, or when taken from the leaves of a plant which had been under the snow all winter; and Carleton? found them to germinate even without a resting period. After wintering, Eriksson found that the teleutospores of P. graminis could retain their germinating power even to the beginning of autumn— September in Sweden. In Victoria the germination of the teleutospores of P. graminis has been tested for several seasons,.and it is found that after a period of rest ex- tending over about eight months, and including the usually hot and dry summer, they begin to germinate in our spring (September), and if the weather conditions are favourable, may retain their germinating power until November. Rusted straw has been kept outside exposed to the weather, and in a room, but no germination took place outside of the above months. When spores have once begun to germinate it is a mistake to suppose that they will all germinate at the same time, for there is a certain irregularity about germination in the open which causes the period of ger- mination to be considerably extended. INFECTION. The mode of infection usually varies in different classes of spores. The germ tube of the uredospore or aecidiospore generally enters by the stomata into the tissues of the host-plant, while that of the sporidiolum bores through the epidermis direct, and this difference in the mode of infection influences the stage at which it occurs in the development of the host-plant. The sporidiola are, as a rule, only able to infect young and tender portions of the plant; but the uredospores and aecidiospores can evidently attack old and fully developed organs. Further, since the germ-tube of the sporidiolum in piercing the epider- mal cells must dissolve the wall at the spot where it enters, there is evidently a reciprocal influence exerted between the parasite and its host ; but even in the case of the uredospores and aecidiospores, where an entrance is effected through the stomata, there also exists some mutual relation, for it is only in certain hosts that the parasite can grow and develop. This relation will be more fully dealt with when the origin of para- sitism is considered, but meanwhile the fact may be emphasized, that the mere entrance of the germ-tube through the stoma does not constitute infection. Miss Gibson! carried out infection experiments with uredo- spores and aecidiospores of various rusts on a number of plants other than the original hosts, and she found that while the germ-tube may enter the stoma freely, yet, once inside, death ensues sooner or later, and in no single instance was a haustorium formed. The fungus was unable to penetrate the cells of the foreign host-plant, and so died of starvation. The period which elapses between the entrance of the germ-tube jnto the host-plant and the appearance of the result is known as the incubation period. During this time the germ-tube grows and ramifies among the tissues, abstracting nourishment from the cells by means of haustoria, and finally proceeds tto the formation of fresh spores. The first visible trace of this does not generally appear before eight days, but, according to the nature of the fungus, it may take much longer. Schimper, in his masterly work on Plant Geography, begins with the statement—‘‘ No factor affecting plant life is so thoroughly clear as the influence of water,’’ and even for parasitic fungi this factor is of prime importance. Smith! has determined the water relation for Puccinia on asparagus, and probably the same prin- ciple applies in a genera! way to other rusts. From a study of the direct ike) Reproductive Organs. relation or the effect of atmospheric moisture upon the spores or mycelium, it has been shown that dew is absolutely necessary for infection, and of more importance than rain, and, in fact, that without dew there can be no infection. Further, that the effects of atmospheric dryness not only influence spore germination, but also spore production, and the aecidial and uredo stages are checked thereby, but if the mycelium is not completely destroyed, the teleuto stage may appear independently of conditions un- favorable to the others. The indirect relation of water or the effect of soil moisture, which acts upon the parasite through its host, has also been studied and shown to be of great importance. An abundance of soil moisture at the growing season, in the case of asparagus rust in California, is stated to increase the vigour and vitality of the host, and retard the development of the fungus. That the growth of the fungus is retarded by increased vitality of the host scarcely agrees with Marshall Ward’s conclusions in regard to brome rust (Chap, XVIII.). That the weather exercises a commanding influence in hastening the development of rust in wheat is abundantly shown by its rapid spread in hot ‘‘ muggy ”’ weather, especially when accompanied by heavy dews. Irrigation before ploughing gives the wheat a good start, but if applied in the spring it makes the wheat soft and very liable to rust, a case in which great vigor of growth of the host is followed by a strong development of the rust. While the ordinary mode of infection is as stated above, exceptions may occur. Thus, according to De Bary, the germ-tube of the sporidiolum of Puccinia dianthi (P. arenariae) may enter by the stomata, and Bolley* gives illustrations to show that the germ-tube of the uredospores of P. triticina may enter direct through the epidermal cells as well as by the stomata. SUPPRESSION OR OMISSION OF SPORE-FORMS. As already pointed out in the Introduction, the complete cycle of develop- ment follows an invariable order. The germinating teleutospore gives rise to sporidiola, from the mycelium of which arises the spermogonia and aecidia ; later the uredospores appear, and finally the teleutospores complete the cycle. The aecidio, uredo, and teleutospore forms are represented respectively for convenience by the Roman numerals I. II., III., and if the sporidiola arising from the teleutospore are designated by IV., and spermogonia by a cypher, then it will be comparatively easy to represent the different stages diagramatically. A complete cycle of development will be repre- sented thus—O., I., II., III., IV. The teleutospore with its sporidiola is believed to be a constant factor in the cycle, although there are various rusts in which it has not yet been found, so that I. or [I., or both, may be omitted or suppressed, as well as O, which, however, is rarely absent. The germinating sporidiolum produces a mycelium which may in turn give rise to spermogonia and aecidia. These may either occur on the same species of host-plant as that which bears the teleuto- spore, and the rust is thus said to be autoecious, or they may occur on a totally different plant when the rust is said to be heteroecious. The aecidio- spore on germinating may skip the uredo stage, and directly produce the teleutospore, and thus the cycle is shortened. There are numerous examples of this in Australian forms, among which may be mentioned the rust on the marigold (P. calendulae), and that on the daisy (P. disdincta). This variation in the alternation of spore-forms has been used _ by Schroeter as a basis of grouping, and although these biological sections by no means indicate close affinity, yet they conveniently group together forms which have similar associated stages. Taking the genus Puccinia as an Reproductive Crgans. Il example—and it applies to other genera as well—the complete cycle is designated Eu-puccinia, and represented diagramatically as O., I., II., Iyi4 1M. Then the stage in which the uredo does not appear is known as Pucciniopsis, and represented by O., I., III., IV. Again, the germinat- ing sporidiolum may produce a mycelium which bears spermogonia and ure- dospores, thus skipping the aecidial stage. This stage is called Brachy- puccinia, and represented by O., II., III., IV., or the spermogonia may like- wise be suppressed when practically only half of the cycle is retained, and it is known as Hemi-puccinia, represented by II., III., IV. This is a stage which is probably based upon imperfect observation, and the presumed absence of the spermogonia. Further, the germinating sporidiolum may skip the aecidial and uredo-stage and produce the teleutospore direct, with its accompanying spermogonium. This is known as Lefto-puccinia when the teleutospore germinates immediately, and J/icro-puccinia when it undergoes a period of rest. It would be represented diagramatically as O. III., IV. As might be anticipated, the greatest number of species have a complete life cycle, and next to that come probably those species in which the life cycle is reduced to its lowest limits, thus showing that the aecidial and uredo generations may be dispensed with. In the former case there is, as it were, a succession of forms adapted to the varying seasons, well fitted to meet any sudden changes, and living upon the same, or having a change of host-plant as may be found most convenient, while in the latter the change consists not in the variety of spore-forms, but in having a general purpose spore, which can either germinate upon the living plant as soon as it reaches maturity or undergo a period of rest in the decayed organic matter before producing sporidiola. Hollyrock rust, or Puccinia malvacearum, is a good illustration of a single-spored form adapting itself to the most varied con- ditions, and making its way in the world. The complete scheme for grouping Puccinias, according to the alterna- tion of their spore-forms, is as follows :— Eu-puccinia, O., I., I1., I1T., TV. Puccimopsis, -O:, 1:7 Tit. 21V: Brachy-puccimia, OYE, Te TV: Hemi-puccinia, II., III., IV. Lepto-puccinia, O., III., IV. (Teleutospores germinating imme- diately). Micro-puccinia, O., III., IV. (Teleutospores germinating after a period of rest). J REPETITION OF SPORE-FORMS. In connexion with the suppression or omission of spore-forms, we may also consider the repetition of spore-forms, because it would appear that in many instances the suppression is brought about or initiated by one of the spore-forms being able to repeat itself in the course of the cycle, and thus making up for the loss of one member of it. It is the doctrine of substitution in another form. This will be more conveniently dealt with when treating specially of the aecidio and uredo spores, where it will be seen that when the uredo generation is suppressed or omitted, the aecidio- spores often repeat themselves, and when the aecidial generation is omitted the uredospores repeat, themselves. INVESTIGATION OF SPORES. The microscopic investigation of rust spores is comparatively easy, although it requires careful observation with regard to their minute details. 12 Reproductive Organs. If the loose spores are examined as to their individual structure, whether aecidio uredo or teleutospores, it is simply, necessary to mount them direct, and | find the most convenient mounting medium to be glycerine and water in equal proportions. For permanent preparations glycerine jelly may be preferable; but for the rapid examination of material the above serves very well, and where desirable the mount can be preserved. The surface markings of the spores are often obscured in mounting, and have sometimes been overlooked by otherwise good observers. As a general rule, they are best seen in the dry condition and without any special pre- paration, but they are usually also seen in glycerine and water, especially if examined when freshly mounted. The number and position of the germ-pores require to be carefully studied, since they are often of specific value, and there are various re- agents which show them up with great clearness. Among these, I have successfully used lactic acid and Bismarck brown. A 50 per cent. solution of lactic acid was used as a mounting medium, then the spores were added, and the slide was heated over a spirit-lamp just until the liquid reached the boiling point. Sometimes it is necessary to boil for a little in order to get the best results, taking care not to burst the spores, but as a rule bringing it to the boil is sufficient. After the preparation has cooled, the cover-slip is placed over it. Some use a mixture of equal parts of glycerine and alcohol for mounting the spores before adding the acid. Boiling in lactic acid not only drives out the air and makes the spores more transparent, but it swells them to their normal shape and size, and not only brings out the germ-pores, but the surface markings as well. For pale-coloured spores or spores which have partially lost their colour through age, I have found nothing to surpass Bismarck brown. The clear germ-pores show up well against the brown stain. The spores are simply laid in the smallest possible amount of water or water and glycerine on a slide, then thoroughly separated by stirring with a needle. Sufficient of the stain is next applied, covered, and after gentle boiling the spores are ready to be examined. It stains quickly, but does not overstain, and is fairly permanent. Soaking hard tissues for twenty-four hours in a solution of caustic potash or caustic soda softens them wonderfully, and mounts made from minute pieces of the material thus treated are often extraordinarily beauti- ful, and the relation of the parts to one another is preserved in a surpris- ing manner. Though soaking for several days nearly always destroys the colour of the spores, yet details may sometimes be distinguished with a certainty not obtainable by any other method. For determining the average size and shape of the spores I know nothing better than photography. Numbers of spores are photographed together, and the general shape can be determined by comparison, while the size is deduced from the exact measurement of individuals in large groups. In this way the average size has been obtained for the teleuto- spores chiefly, of all the species accessible for observation. At the same time a large number were measured direct by an eye-piece micrometer and the results compared. All the microscopic investigations were made with Zeiss’ apochromatic objectives, and the photomicrographs with lenses of Watson’s holoscopic series. Spermogonia and Spermatia. 13 CHAPTER IV. SPERMOGONIA AND SPERMATIA. The spermogonium, sometimes called pycnidium, is a small punctiform body, hemispherical to flask-shaped, produced beneath the epidermis or cuticle, and ultimately the narrow neck bursts through in order to allow the contents to escape into the air. The narrow opening is generally sur- rounded by a brush of sterile projecting stiff hyphae, the so-called para- physes, and in the interior of the spermogonium there are numerous con- verging hyphae surmounted by very minute oval or rounded bodies borne in short chains—the so-called spermatia. ‘These bodies were considered to be of the nature of male sexual organs, hence the name; but whatever may have been their original function, now lost in the course of develop- ment, there is no reliable evidence to support the view of their being sexual in function. The spermatia are embedded in a sugary secretion, and though it is not known whether this serves to cause the spermatia to germinate, insects are probably attracted to the spermogonia sometimes by means of this sweet bait, and also by their powerful and penetrating odour, as in Puccinia suaveolens Pers., which is so named on account of its sweet scent. The honey colour of the spots may also serve as an attraction, and the project- ing hairs or paraphyses are believed to retain the spermatia and prevent them being washed away. Colour, scent, and honeydew will thus co-operate in alluring insects to the spot, and the evident resemblance of these relations to those which prevail in the fertilization of flowers by insects naturally led to the belief of the spermogonia and spermatia being concerned in some way with the fertilizing process. This view was further strengthened by the fact that in Lichens, which possess similar structures, there called pycnidia, a true process of fertilization occurs. But actual experiments fail to prove any such connexion, and the probabilities are that the original function has disappeared owing to modifications consequent upon! the fungus becom- ing parasitic. Spermatia do not germinate in water, but do so when placed in a suitable nutritive solution, such as white cane-sugar dissolved in water. Germination consists in a minute prolongation at one end, which ultimately becomes like the parent spore, and thus, as far as present know- ledge goes, the spermatia are isolated structures, and do not enter into the regular development of the fungus. Spermatia, whatever may be their function, do not occur as solitary spore-forms, but always precede or accompany one of the others.” They are usually associated with aecidia, but this is not invariably the case, for there may be aecidia without them, and in the absence of aecidia they may be associated with other spore-forms, such as uredospores in the case of Uromycladium robinsoni, Puccinia hieracii (Schum.) Mart. &c., and teleutospores, as in P. liliacearum Duby and Uromycladium tepperianum (Sacc.) McAlp., and either uredo or teleuto spores, as in U. maritimum. The same mycelium which proceeds from the teleutospores, and produces the spermogonium, also produces aecidio uredo or teleutospores, as the case may be, although it may seem a needless waste of material and an unnecessary act, since the one is left behind in the race, while the others 14 Spermogonia and Spermatia. continue their further development. In a paper by Arthur? on the Zaxo- nomic Importance of the Spermogonium, he shows that, in the first place, ihe presence of the spermogonium, along with its associated spore-forms, gives important information regarding the length of the life-cycle. Thus he concludes that if spermatia and uredospores arise from the same mycelium, aecidia do not occur, and if spermatia and teleutospores thus arise, neither uredo nor aecidio spores will occur. There are cases, how- ever, in which the spermogonia are found in association with both uredo and teleuto spores, as in Uromycladium maritimum, U. notabile, and U. robinsoni. When the spermatia are associated with aecidia, it is only where teleutospores and aecidia arise from the same mycelium that it can be definitely stated that there are no uredospores. In the second place, the characters of the spermogonium, such as posi- tion, size, form, and colour, and its relative position to the accompanying spore-forms, furnish characters for positive identification, although of minor value. There is an interesting relation of the spermogonium to other spore-forms to be noted in the cases afterwards referred to, where there is a repeated formation of aecidiospores, uredospores, or teleuto- spores, as the case may be, and these spore-forms do not directly proceed to their normal development. In such cases, as far as our present know- ledge goes, the spermogonium is the only one which does not repeat itself, as stated by Arthur? :—‘‘An observation more pertinent to our inquiry is that the spermogonium occurs but once in the cycle, not being repeated with each generation of repeating aecidia or uredo. In case the teleutospore takes on the conidial function (repeating process), it is uncertain whether the spermogonium is repeated with each summer generation or not. In Puccinia malvacearum and similar Lepto-Uredineae, the spermogonium seems to be wholly suppressed even with the first generation in spring.’’ The question of sexuality has been raised in connexion with the presence of nuclei, but what constitutes an act of fertilization is interpreted differ- ently by different authors. Sappin-Trouffy?, for instance, has observed in Uredineae having the various stages the following nuclear cycle :— Uni-nucleate.— Mature teleutospores. S poridiola. Mycelium, producing spermatia and aecidiospores. Spermatia. Bi-nucleate.— Aecidiospores. Mycelium, producing uredo and teleutospores. Uredospores and Young teleutospores. In the mature teleutospore the two nuclei fuse, and this fusion was regarded by Sappin-Trouffy as an act of fertilization, but the fusion of the nuclei may be interpreted otherwise. Blackman? has confirmed the above nuclear cycle, and concludes that the spermatia are male cells which have become functionless, the nuclear characters being those of male cells and not of spores. The fertile cell of the aecidium or primary aecidiospore becomes bi- nucleate by the nucleus of a neighbouring vegetative cell migrating through the wall, and this association of the two nuclei Blackman considers to be fertilization rather than the act of fusion in the teleutospore, since the fertile cell is stimulated to further development by the entrance of a nucleus from without.—(Note 2, page 75. Spermogonia and Spermatia. ms Massee also considers the aecidium to be a sexual product, and both authors agree that the spermatia are not concerned in it. If the spermogonia and aecidia represented male and female reproductive organs, a distinct alternation of generations would be present, the spore-bearing stage or sporophyte commencing with the fertilized cell in the aecidium, and the egg- bearing stage or gametophyte starting with the uni-nucleate teleutospore. But the most probable view is that the spermatium is a functionless organ, and its presence is an indication that the ancestors of the rusts may have possessed an alternation of generations similar to that referred to above. 16 Aecidia and Aecidiospores. CHAPTER V. AECIDIA AND AECIDIOSPORES. The aecidia, or cluster-cups, as they are often called, are usually brightly coloured, and attract attention not only from their colouration, but from their elegant forms as well. The mycelium derived from the germ- tube of a promycelial spore may first produce its spermogonia, and then proceed to the development of aecidia, or aecidia may be succeeded by aecidia. The spore layers are contained in a receptacle or pseudo-peridium, which is formed from a simple layer of flattened sterile cells. It increases in size by the formation of new cells at its base, and is cup-shaped or cylindrical, rupturing at the apex to allow the escape of the spores. The aecidiospores are always unicellular, and are arranged in linear series, arising from densely-crowded, erect hyphae or basidia in basipetal order. The young spores are at first separated from each other, according to De Bary, by sterile, intermediate cells, which are soon, however, absorbed, and this makes it often difficult to prove their presence. From the mode of their formation, from above downwards, the ripe spores are at the top, and readily separate to be blown away, while the young spores become polygonal from mutual pressure, lateral and lengthwise. The spores have usually a colourless membrane, with the exception of those of Gymnosporangium, in which it is usually a deep brown, and in the great majority of species are provided with points, spines, or warts, to make them adhere in order to germinate. The granular contents are coloured, as a rule, with an orange-yellow or orange-red oil, although this also occurs in many uredo and teleutospores. Germination takes place as in the uredospores by means of a simple cylindrical germ-tube which enters through the stoma into the interior of the host-plant. At certain weak spots in the membrane germ-pores are formed, which are usually only distinctly visible at germination, owing to the swelling of the membrane at these spots, and through these the endo- spore is protruded in the form of a tube. As the aecidiospore germinates very readily in water, the process of germination can be easily followed. A germ-tube rarely arises from more than one pore, and the contents of the spore gradually pass into it along with the orange-colouring matter, so that the spore is ultimately emptied and the endochrome is towards the extremity of the tube. I found aecidiospores of Puccinia tasmanica, from the common ground- sel (Senecio vulgaris), to germinate freely in the manner indicated. They were very plentiful in November, and in a drop of water they began to germinate within a few hours, and soon produced germ-tubes of consider- able length. As to the length of time that aecidiospores retain their germinating power there is much difference of opinion. De Bary states that they may retain it for some weeks, while Plowright considers it a matter of hours. Eriksson, on the other hand, found that the spores of Aecidium berberidis, for instance, were very capricious and uncertain in their germination, but there is always the possibility that although the spores do not germinate in water, they may infect a host-plant when brought into direct contact with the living leaf. According to Bolley, the aecidiospores on barberry and other hosts aré still capable of germination, even after lying in the herbarium for some time, or being sent through the post. Aecidia and Aecidiospores. sy The development of the aecidia has been traced by De Bary, Neumann], and others. The hyphae derived from the promycelial spores form at certain points, deep down in the parenchyma of the leaf, little compact bodies which have been called primordia by De Bary, because they are the beginnings of the aecidia. These bodies gradually increase in size by the rapid multiplication of the mycelium until they assume a spherical form, only being slightly flattened at the part immediately beneath the epidermis, and considerably thickened at the base. If sections are made at this stage the differentiation of the cells is seen to have begun. From the dense basal layer of hyphae arise numerous, closely-crowded, short, erect hyphae, somewhat club-shaped, and generally known as basidia. From each of these erect hyphae an apical cell is separated off, and beneath that another, and so on until a linear series is formed. At the same time, as the basal cells give rise to the so-called basidia, the surrounding cells develop into the external envelope or peridium. At first they are absolutely indis- tinguishable from the others, but after the third or fourth division they are seen to be much broader. Then, simultaneously with the formation of the first spores, they acquire their characteristic markings and polygonal form. At first the peridial cells are filled with the coloured protoplasm or endo- chrome, but the colour gradually disappears. With regard to the peridial cells, Fischer! has shown that in Gymnosporangium the sculpturing of the walls may be used for the dis- tinction of species, and while in the genera Puccinia and Uromyces these cells are much more uniform in their markings, yet there is considerable variation. Mayus! has examined peridial cells from several species of these two genera, and has found that within the limits of the same species the nature of the peridium undergoes variation under the influence of external conditions. These variations chiefly consist in the relations of the lumen and the thickness of the wall, the lumen being relatively larger in shady places and the converse in sunny places. The typical aecidium possesses an external envelope of cells or peri- dium, which surrounds the spores, and when this becomes ruptured at the top to allow the escape of the spores it assumes the form of a cup. But the envelope may assume different forms, or even be absent, and then different names are given to it for convenience, although in its essential character of spore-formation it is still the same structure. When the peri- dium is elongated, and often horn-like, it is called a Roestelia, or it may be rather irregular in shape and confined to coniferous plants, when it is called a Peridermium (not represented in Australia), and when the peridium is absent it is known as a Caeoma, as in C. apocyni. Even in the genus Puccinia the pseudo-peridium is wanting in indi- vidual species. In a number of species, as in Puccinia prenanthis, the aecidium is sunken and formed by the more or less altered tissue of the host-plant, and a special pseudo-peridium is either completely wanting or very imperfect. Such aecidia are to be regarded as intermediate forms between the true distinctly walled aecidia and the caeoma form. The origin of the aecidium has given rise to a good deal of discussion, and it is not universally accepted that it originates from non-sexual cells. Massee!, in his paper On the presence of Sexual Organs in Aecidium, considers it to be a sexual product, and has even drawn the swollen ends of two mycelial hyphae imbedded in the tissues of the host-plant, supposed to be in the act of conjugation. Arthur, in his Problems in the Study of Plant Rusts,? and The Aecidium as a Device to restore Vigour to the Fungus' comes to the conclusion that ‘‘ the aecidium, with its accom- panying spermogonia, represents the original sexual stage of the fungus, and that it still retains much of its invigorating power.” 18 Aecidia and Aecidiospores. But it is quite possible that the time of appearance of the aecidia has something to do with their invigorating power, if such exists. They usually appear in the spring, when the-first rush of vegetation commences, and naturally the parasite shares in the strong growth of the host-plant. The nature of the host will likewise affect the result. It may appear on the leaves of an annual such as Helianthus annuus, which also bears teleutospores, or on those of a deciduous shrub such as barberry, the uredo and teleutospores of which occur on wheat and other grasses. But it is a striking fact that the aecidium is so rare upon a grass-that, until the discovery of an aecidium on a species of Danthonia in Victoria, only one instance was known, viz., Puccinia graminella, in which the aecidia and teleutospores occur together, the latter being often very rare, or wanting aitogether. Repeated Formation of Aecidia—The normal development of heteroe- cious fungi, as well as of ‘autoecious forms, follows a regular cycle, as already shown. In those forms possessing all stages in the life cycle, the sporidiola produce only the aecidia, and the aecidiospores in turn give rise only to uredo and teleutospores, as in Uromyces trifolit (Alb. & Schw.) Wint. But among those autoecious species which produce aecidiospores and teleuto- spores without uredospores, this regular succession of forms may be departed from in some cases, and ‘the aecidiospores, provided the mycelium is not perennial in the host, may repeatedly produce new aecidia before the teleutospores are reached, as in P. senecionis Lib. Spermatia Sporidiola Aecidiospores Teleutospores Aecidiospores Fig. 5. _. This repeated formation of aecidia was principally investigated by Dietel, who named the aecidia arising directly from the germination of teleutospores ‘‘ primary aecidia,’’ and those arising from the germination of aecidiospores ‘‘ secondary aecidia ;’’ and it was noticeable that spermo- gonia were usually absent from the latter. Thus the germinating spori- diolum may produce a mycelium which bears only aecidia; but the aecidio- spores, instead of giving rise directly to teleutospores, may repeat them- selves for several generations, and then give rise to teleutospores. How- ever, in a complete cycle, the aecidia originate only from sporidiola, while . in an incomplete cycle the aecidia at first originate from sporidiola, and then repeat themselves. Uredespores. 19 CHAPTER VI. UREDOSPORES. Uredospores may originate from the hyphae developed from the germ- tube of an aecidiospore, a promycelial spore, or another uredospore. They are generally ovate or elliptic. and are developed singly on the ends of separate short upright hyphae, known as basidia. In some genera, however, such as Coleosporium and Chrysomyxa, they arise like the aecidiospores, in short chains, and thus resemble Caeoma-forms—in fact, they are sometimes regarded as such. The spore-bearing hyphae are crowded together just beneath the cuticle, or epidermis, of the plant, and such an aggregation is known as a spore-bed, or sorus. The uredospores are always unicellular, and néver smooth, the mem- brane being beset with projections in the form of short prickles (echinulate) or fine warts (verrucose). Two-celled uredospores have been described and drawn by Roze! and Jacky?. in Puccinia chrysanthemi, but they are very probably monstrosities, as suggested by Sydow, two unicellular spores becoming united when young, and growing up together. In the same rust I found, in one instance, two uredospores. produced on the same stalk, the one slightly beneath the other; but this was merely a freak. They differ generally from the aecidiospores on the one hand in the mode of forma- tion, and from the unicellular teleutospores of the genus U/romyces on the other, in having two or more germ-pores, and this character also dis- tinguishes them from the mesospores. Only in exceptional cases is there only one, as in Puccinia monopora. They vary in colour, generally being some shade of orange or brown, and in the brown spores De Bary has shown that, as in teleutospores generally, the colouring matter is in the wall, and not in the contents. Germination occurs similarly to that of the aecidiospores. When ripe, and kept moist, a germ-tube is readily protruded through one or more of the germ-pores, and this enters the host-plant by a stoma, and! in the interior develops a mycelium like that from which it originated. It is interesting to notice that in some cases the uredospores may be produced, not only at the surface, but within the tissues. This happened with Puccinia pruni, in a peach fruit, where spore-beds of rust freely producing uredospores were imbedded in the tissue, in more or less rounded cavities, up to 5mm. below the surface. The decaying fruit would form a splendid matrix for preserving the spores till next season. Since they are chiefly produced in the summer, and adapted, as a rule, for rapid germination, they are often spoken of as summer spores, and as soon as they arrive at maturity become detached from their stalks. Repeated Formation of Uredos pores. —Just as aecidiospores may pro- duce aecidiospores for several generations, so may uredospores produce uredospores. ‘This is well seen, “for instance, in P?. graminis, where uredo- spores are produced direct from the uredospores without the intervention of aecidia and teleutospores, as is the case in Australia, and this repeated formation of uredospores may continue indefinitely. But there are several cases where the first-formed uredospores are different from those produced later, and, in order to distinguish such forms, the two kinds of generations are known respectively as primary and secondary 20 Uredospores. The primary generation appears in the early spring, and originates either by infection from the promycelial spores, aecidiospores, or, it may Spermatia Sporidiola Uredospores Teleutospores Uredospores Fic. 6. be, from a perennial mycelium. ‘The spore-layer is usually distinguished by its larger size, and the corresponding injury it causes to the host- plant; while the secondary generation, produced by infection from the preceding uredospores, has a smaller spore-layer. A well-investigated and very striking case is seen in Triphragmium ulmariae, in which the primary and secondary uredospores generally re- semble each other; but the sori of the former are much larger and pro- duced in great abundance, occurring, on the stalks and midribs of the leaves, while those of the latter are small and scattered on the under sur- face of the leaf. So striking is the difference that a special name has been proposed for the sorus, epzteosporiferous and epiteospore for the primary spore; but it is quite superfluous, since the larger and more prominent sori of the primary generation may be accounted for from the strong vigour of growth in the plant at the time when the first infection occurs. The wintering of the rust-fungi, in the form of the uredo, depends on the nature of the rust itself, and also on that of the host-plant. If any portion of the host-plant remains green and succulent during the winter, then the fungus has an opportunity of surviving, and it is thus seen that climatic conditions have a deal to do with the persistence of the fungus. When the winter is mild and green vegetation flourishes, the mycelium of the rust fungus may continue to grow, and may even produce spores; whereas, if the winter is severe, and the mycelium does not remain in the perennial parts of the plant, then the continuance of the fungus is likely to be by teleutospores, which can last through the winter on dead stems or other decaying vegetable matter. This so-called winter- ing of the uredo depends so much on the climate that in a mild climate the fungus may perpetuate itself exclusively by uredospores; whereas, under severe conditions, it has to resort to teleutospores. A very striking case is recorded by Lagerheim!, in Uromyces fabae (Pers.), De Bary, which in Europe passes through the three stages of the aecidio-, uredo-, and teleuto-spore, while in Ecuador it only produces the uredo-form. | _Heteroecism, or alternation of generations, is an arrange- ment suited to conditions where the seasons are variable, but in an equable climate such as Ecuador there is no occasion to produce such a variety of spore-forms, and so the fungus adheres to the one which serves its purpose best. Australia is also a case in point as far as Puccinia graminis is con- cerned, and it is necessary to remember that our seasons are the reverse of those of the Old World. Our cereal crops are generally sown in the autumn months of April and May, or even earlier, and the harvest is Uredospores. 21 reaped at the end of spring, or beginning of summer in November and December, so that it is the heat and drought of summer, not the cold and wet of winter, which the fungus has to provide against. In fact, the wintering of the uredo is a misnomer here, for it is the excessive dryness and heat which is most injurious. Bearing this in mind, it is easy to understand that P. graminis, although it still continues to produce a certain amount of teleutospores, is per- petuated from season to season by means of uredospores. Self-sown wheat or oats, or even the aftermath of either of these crops cut for hay, is always more or less rusty during the late summer and autumn, the uredospores being freshly produced then through the depth of winter. The teleutospores of P. graminis seem unable to infect the barberry in Australia, and this heteroecious rust would appear tto be fast becoming like Uromyces fabae reduced to its lowest limits, and reproducing itself only by uredospores. Of course the absence of the barberry would tend to weaken if not destroy the capacity to produce the aecidial stage. Although the germination of uredospores during winter has already been generally referred ‘to, some definite instances may be given here, and I will select those of Puccinia graminis, P. triticina, and P. chrysanthemi from a number of tests made. The rust appeared on some self-sown wheat, which ‘was growing vigorously during winter (June), and on placing the uredospores of P. graminis in a drop of water, they were found to germinate sparsely in seventeen hours, and in twenty-one hours they germinated freely and very generally. At the same time, and from ihe same wheat plants, uredospores of P. ¢rztzczna were placed under similar conditions, and they also began to germinate within 21 hours, but after several hours longer, only a few were germinating, and not too luxuriously. The uredospores of P. chrysanthemi were also taken from green leaves in May, and they germinated freely, producing long curved germ-tubes. Thus uredospores taken from growing plants fate the winter are cap- able of germinating, and this proves conclusively that self-sown, or volunteer wheat, on the headlands or elsewhere in the neighbourhood of growing crops is one of the means whereby rust may be continued from season to season. In one case, which I have ey ery reason to believe is quite exceptional, the season’s wheat, sown at Wellington, New South Wales, in April, was badly rusted as early as May, but, as a general rule, it is exceedingly difficult, even for the trained observer, to find more thang an odd speck of rust in a crop of wheat earlier than the end of September, though there may be plenty on self-sown plants. There is a conflict of evidence, however, as to the conditions under which germination takes place when the spores are not taken direct from the fresh and growing plant. Eriksson (Eriksson and Henning’) found that the uredospores of P. graminis lost their capacity for germination during the winter if exposed to the weather, but retained it if kept inside, and even then it gradually disappeared, while Jacky? found that the uredospores of chry santhemum rust still retained their germinating power, after exposure to the weather for 66 days, from rst December to 5th February. And Miss Gibson kept spores of the same rust in a dry test-tube in a cool room for 71 days, from March to May, and at the end of that time about one quarter germinated, while a week after none germinated. The uredospore is primarily a spore for the rapid reproduction of the species. As a rule, it is produced in immense numbers, it is provided with a thin wall, having projections of some sort to act as a holdfast, and it generally infests the leaf or sheath, so that nutrition is not directly 22 Uredospores. interfered with, as in the case of ithe teleutospores on the stem. But the uredo may become inured to unfavorable conditions, such as drought or cold, and carry on the life of the species, independent of the teleuto- spore. This is well seen in Puccinia poarum, for in both Europe and America it has been found on the leaves of Poa pratensis even after the melting of the snows, and in Australia it occurs on Poa annua throughout the winter months, the rust disappearing with the withering of the host, which generally happens early in October. An extreme case seems to have been reached in P. vexans, Farl., where, in addition to the ordinary uredo, there is a specialised form to which the special name of amphispore has been given, which is thick-walled, strongly papillate, and only ger- minates after a period of rest. It is quite common for the uredo-layer to be attacked by the parasitic fungus, Darluca filum, Cast., so much so that it has been found upon 24 per cent. of the species of Puccinia. It is somewhat unfortunate that Dr. Cobb? has confounded this parasite with spermogonia, producing spermatia, for in referring to peach rust, he writes:—‘‘I frequently find among the uredospores of a pustule of this rust, small black pycnidia, producing a multitude of two-celled spores, which, when placed in a moist chamber, often bud and multiply after the manner of yeast plants, but which oeca- sionally produce a mycelium. These two-celled bodies have, as I have on several occasions publicly remarked, no slight resemblance to the so- called spermogonia of several species of Aecidium.’’ Although spermatia are well-known to be unicellular, yet Carleton ? quotes this authority for the statement that ordinary germ-tubes are produced in the germination of spermatia as well as in the other spore-forms. This rust parasite is very commonly distributed, attacking the mycelium and probably checking the development of spores. It occurs on aecidia, uredo, and teleuto-layers, and is recorded on Uromyces (9), Uromycladium (1), Puccinia (22), Phrag- midium (1), and Aecidium (2). Paraphyses most commonly occur in connexion with the uredosori, and are found in Australian species of Puccinia, Melampsora, and Phragnidiim as well as in Uredo. Occasionally they arise in both uredo and teleuto-sori, as in Puccinia magnusiana and P. purpurea, and sometimes they are variable in their presence as in Puccinia poarum, where Plowright found none in Britain, although they are common in Australian specimens. In Phragmidium subcorticium not only are the uredosori provided with paraphyses, but like- wise the aecidial patches, since they are without a surrounding membrane. The following are the known Australian species, with paraphyses in their uredosori :-—Puccinia lolii, P. magnusiana, P. poarum, P. pruni, P. purpurea; Melampsora hypericorum, M. lini; Phragmidium barnardi, P. subcorticium,; Uredo kuehni, and U. spyridiz. Teleutospores. 23 CHAPTER? Vil: TELEUTOSPORES. Teleutospores are very varied in theic shape and size, and are on that account often regarded as the characteristic form for distinguishing genera. They may be produced directly from the mycelium of the aecidiospore or uredospore, or indirectly from the teleutospore itself by means of the sporidiola. As the name denotes, it is the last formed, or finishing spore, in the life-history of rusts, although in many instances it is the only spore formed, and there are cases where it has not yet been found. Where it exists alone it may be that the other spore- forms originally existed, but have now come to be dispensed with, and where it does not exist it may be a degenerate type like the other, only it is the teleutospore form which has been dropped. Itisa question, however, whether it is not a necessary stage in the life of every rust, and its apparent absence is simply owing to our not having discovered it. As an example, Z/redo symphyti, DIC. was considered by De Bary to be an independent species, and having lost its other spore-forms to be capable of existing without them, but Bubak? afterwards found the teleuto- spore in Bohemia, and so it may turn out in other cases. They arise like the uredospores in smaller or larger spore-beds, often closely crowded together, and usually directly beneath the epidermis which they often rupture. It is seldom that they originate directly beneath the cuticle. The colour of the spore layer is very variable, but generally it is darker than the uredo layer, being dark-brown to blackish, and only warely reddish. In the simplest cases teleutospores are unicellular, and originate in a similar manner to the uredospores. The spore-bed, consisting of inter- lacing and crowded hyphae, gives off erect branches, which become swollen at their free ends, and the finely granular protoplasmic contents are invested by an.inner membrane, or endospore, in addition to the outer or epispore, which becomes relatively thick and dark in colour. The teleutospores are -generally formed towards the end of the active vegetative period of the host-plant, and are often called winter spores in contrast to the uredo or summer spores. They are specially adapted and equipped for continuing the species over periods of drought, or damp, or cold, or seasons of scarcity. This is seen in the firm outer wall, which is often sculptured in various ways, as well as in the reserve material stored up in the contents. Sydow! states that in all Leptopuccinieae, or those only possessing teleutospores which germinate at once, the epispore is perfectly smooth ; but there is one exception in Australia—/P. plagianthi. In other groups the epispore may be smooth, warted, striated, &c. The portion of the hypha supporting the spore becomes the stalk, or pedicel, by means of which it wemains attached to the spore-bed for a longer or shorter period. In Endophyllum the teleutospores originate in chains, and are produced within a peridium similar to aecidia. They would be called aecidiospores, only they produce a four-celled promycelium, which bears promycelial spores. They serve the purpose of summer spores, since they germinate as soon as they are ripe, and the fungus winters by means of its mycelium in the host-plant. ' 438. B 24 Teleutospores. This genus is so anomalous, that it is now coming to be regarded, not as an independent form, but as a biologic genus in connexion with Puccimia - or U/romyces. ; 3 Teleutospores may be simple, as in Uromyces, or compound as in Puccinia. In the newly-constituted Australian genus, Uromycladium, the teleutospores are of the Uromyces type, but they have the peculiarity of being produced, not solitary at the end of a stalk, but in groups sometimes accompanied by a colourless vesicle. In Uromyces and Uromycladium there is only one germ-pore, situated at the apex, and the membrane is generally smooth, although it may be warted or striated in Uromycladium. As yet there are known only two Australian genera with compound spores—Puccinia and Phragmidium, in the one case consisting of two spore- cells, and in the other of three or more in a vertical row. In Puccinia the germ-pore of the upper cell is at the apex, and that of the lower at the side just beneath the transverse partition. In Phragmidium, the number of germ-pores varies in Australian species from one to three in each cell. Dietel! has stated that there is only one germ-pore in each cell of P. darnardi, but three were invariably found by me in examining a large amount of material. Paraphyses are not frequently found in teleutosori, probably because teleutospores are generally so well constructed for withstanding. variable conditions that they do mot require such protection. The best-known ex- ample is that of the old species, Puccinia rubigo-vera, now split up into several, such as Puccinia bromina and P. triticina, in which the teleuto- sori are divided into compartments by the clavate brown paraphyses.—(Note 3, Pp. 75-) It is worthy of note that the teleutospores are capable of ger- mination in the autumn of the year in which they are produced. There are no other Australian species in which paraphyses are confined to the teleuto- sori, but they may occur in connexion with the latter as well as with uredo- sori in Puccinia magnusiana, P. purpurea, and Uromyces phyllodiorum. The germination of the teleutospores of Puccinia graminis in Australia was tested under different conditions, and the most important condition seems to be the season of the year, for they were only known to germinate during the spring months. Badly rusted straw was placed in the cool stores for three months, one portion being kept at a temperature of 4 deg. C., and another at-18 deg. C. A third portion of the same straw was simply kept in the open, and when tested for germination in the spring only the spores exposed to the weather germinated. Another feature of germination worthy of mention is the way in which it is spread over a period of time, and the spores in the different sori are not all ready at once. There seems to be a succession of ripening, for among a patch of sori only one out of every fifteen or twenty will be found to contain spores capable of germination. This shows the necessity for germinating spores in bulk when tests are being made, for you might happen to select spores. which would not germinate, being taken from an unripe sorus. Not only are the spores ready for their work of germination at dif- ferent times, but the sporidiola are produced in succession, for you never find the promycelium bearing its four spores all at once, at least in P. gra- minis. This is well shown in Phate XV., with the germinating teleutospores of P. malvacearum. Mesospores and Amphispores. 25 CHAPTER VIII. MESOSPORES AND AMPHISPORES. In the great majority of Australian Puccinias, 80 per cent. at least, there occur associated with the teleutospores, and quite distinct from the uredospores, unicellular spores which somewhat resemble the two-celled spore in coloration, though generally much paler. It is generally notice- able that wherever the teleutospores are thickened, or apiculate, or pro- longed into processes at the apex, or warty on the surface, these spores possess the same characteristics. The conclusion one would naturally draw is that they are teleutospores in the process of making, with the lower cell wanting, just a survival of what is normal in the Uromyces. From their partaking of the nature of a middle spore-form between Uromyces and Puccinia, they are generally called mesospores, and simply represent an imperfectly developed or abortive teleutospore, which may, however, in certain cases perform the functions of a fully-developed teleutospore, although only one-celled. In the newly-constituted genus Uromycladium there are found in con- siderable numbers among the uredosori, smooth-walled spores smaller than the uredospores, produced singly on basidia and entirely different from the teleutospores, to which the term mesospores has also been applied. Just as there are two kinds of teleutospores, so there may be two kinds of uredospores, which are represented at present in a few species belonging to Uromyces and Puccinia, but have not hitherto been found in Australia. This modified uredospore, while agreeing with the normal uredospore in the mode of germination, possesses a thickened epispore, and a more or less persistent pedicel. | From its partaking of the characters of both spores, those of the uredospore in its possession of two or more germ-pores, and those of the teleutospore in its germinating only after a period of rest, it has been called an Amphispore, by Carleton. AMPIIISPORE. This peculiar kind of spore was first investigated in connexion with Puccinia vexans Farl. This species has a true uredo and teleuto-stage, in addition to a third form of unicellular spore, and the latter was the first to be recognised and recorded. In 1879 it was described as Uromyces brandegei by Peck, the unicellular spores being rough with minute warts, and therefore suggestive of Uromyces. Then, in 1883, Dr. Farlow! found true bilocular teleutospores associated with the supposed U/romyces, and named the fungus Puccinia vexans, the specific name referring to the perplexing nature of the unicellular spores. As Dr. Farlow writes :—“ The perplexing question arises, are the one-celled spores a unilocular form of teleutospores similar to what is known as P. cesatii, Schr., or are they the uredospores of this species?” Their true nature was finally settled in 1897, when Carleton succeeded in germinating them, and ultimately they were found to give rise to two germ-tubes, as in the true uredospore which had been discovered the previous year. Now that the three spore-forms are known in this species, it becomes possible to answer the question, in what respect does the amphispore differ from the teleutospore, on the one hand, and the uredospore on the other. It agrees with the uredospore in being unicellular, and having more than one germ-pore, but differs in B2 26 Mesospores and Amphispores. being strongly papillate instead of echinulate, thick instead of thin-walled, with persistent pedicel and only germinating after a period of rest. Its essential difference from the teleutospore is its unicellular character and the possession of more than one germ-pore. Besides the amphispores, mesospores are very numerous in this species, so that there is a Puccinia provided with two kinds of uredospores, and two sorts of teleutospores. Up till recently this was the only instance known of the occurrence of amphispores, but Arthur® has given descriptions and illustrations of nine different species, one of which belongs to the Uromzyces, in which this form of spore is met with. According to this author, amphispores are mainly developed in arid or semi-arid regions, and represent a resting or winter form of uredospores, being provided with thickened walls to enable them to withstand unfavorable conditions, just like a teleutospore. MESOSPORES. In examining the relatively large number of Australian species of Puc- cinia possessing mesospores, one finds that as a rule they are comparatively scarce in point of numbers, and that while a few may resemble the ordinary teleutospore in colouration the majority are paler and altogether with an immature appearance. But there are a few cases, such as Puccinia hetero- spera and P. simplex, in which the one-celled spores far outnumber the regular teleutospores, so much so that the latter have been frequently over- looked, and there is every probability that they undergo germination, and are therefore unicellular teleutospores in the fullest sense of the term. In P. heterospora there are no uredospores, and the unicellular spores are smooth, and otherwise resemble the teleutospores, while in P. simplex the uredospores are spinulose and yellow, and quite distinct from the smooth unicellular spores associated with the teleutospores. Owing to the teleuto- spores not having been obtained at first, the former has been variously named Uromyces pulcherrimus, B. and C., U. thwaitesi, B. and Br., and U. malvacearum, Speg., and the latter as Uromyces hordei, Rost. In fact, these spores have been regarded as a transition stage from the unicellular Uromyces to the bicellular Puccinia spore. In such cases the one-celled spore functions as a teleutospore, and ithere would be a certain convenience in distinguishing between the undeveloped and immature spores and’ those which are fully formed, and in all probability capable of germination, reserving the term mesospore for the one, and unicellular teleutospore for the other. But it is so difficult to draw the line sometimes, and since it is not desirable to multiply names unnecessarily, I will use ‘the term meso- spore to designate a unicellular teleutospore form in Puccinia and Uromy- cladium, which may either be imperfectly developed and incapable of ger- mination, or fully formed and germinable. The presence of mesospores in a species would seem to indicate its still close relationship to Uromyces, and that its separation from the parent form had not yet proceeded sufficiently far to obliterate every trace of its former connexion, Sporidiola or Promycelial Spores. 27 CHAPTER RUEX. SPORIDIOLA' OR PROMYCELIAL SPORES. When the teleutospore germinates, whether at once or afiter a period of rest, the endospore is protruded through the germ-pore as a germ-tube, and the contained protoplasm passes into it. This germ-tube does not behave like that of the aecidiospore or uredospore, and elongate and branch indefinitely, but it soon ceases to grow in length, and terminates blindly. Hence it has received the special name of promycelium, because it directly produces its spores. The promycelium is soon divided by septa, generally stated as formed from above downwards, but my own observations in regard to Puccinia malvacearum show that the median septum is first formed, dividing the promycelium into two, and then each of these subdivides again into two, making in all four cells, from each of which there is a short lateral protuberance which dilates at the end, and becomes a promycelial spore or sporidiolum. The two upper cells, as a rule, produce their sporidiola first, then the next, and lastly the lowest ; but occasionally the two median cells start first. ‘The name sporidium is often applied to this spore, but since it is already used as equivalent to ascospore, the present name has been proposed by Saccardo. The sporidiola are easily detached, and, provided with moisture, they can germinate at once, and on the surface of a living leaf the germ-tube can pierce the epidermis, and, growing and branching’ in the interior, pro- duces a mycelium similar to that derived from the aecidiospore or uredo- spore. But in the case of grasses the walls of the epidermis often contain much silica, and this may be one of the reasons why aecidia are so scarce in that family. Blackman?! has shown that there is considerable variation in the length of the promycelium, according to the conditions of growth. Teleutospores, germinating in moist air, produce very short promycelia, and form sporidiola almost immediately, while those germinating in drop cul- tures, with their germ-tube submerged, grew to a length only limited by the reserve material, but no sporidiola were formed. On reaching the air, however, their formation took place. ‘The free air necessary to their for- mation is correlated with their distribution by the wind. If the teleutospore be regarded as the final stage of the cycle, then the sporidiolum will be the starting point, and from that there may proceed in regular succession the various spore-forms already enumerated, viz., sper- matia, aecidio, uredo, and teleutospores, back to sporidiola again. All these may occur in the same species, and the general course of development is briefly as follows:—From the teleutospore in the spring, sporidiola are formed which develop on a suitable host-plant a mycelium, from which usually on the upper side of the leaf spermogonia are developed, and either on the same side, but generally on the opposite side, aecidia are soon after- wards produced. Infection by the aecidiospores produces the uredo-stage, and these spore-forms often reproduce themselves. The uredo is specially adapted for tthe rapid spread of the fungus, since from the time of infection up to the formation of new uredospores, only eight to ten days may elapse. Finally, along with the uredo, or in special layers, teleutospores arise which, on germination, produce again the promycelia and sporidiola, and thus complete the course of development. This is the typical mode in which the alternation of spore-forms occurs in many species belonging to different genera, but there is often variation in the order, or even omission of some of the stages. So constantly are aecidial or uredo stages associated 28 Sporidiola or Promycelial Spores. with at least another stage, that when found alone or isolated they are regarded as incomplete, and it is taken for granted that the associated form has yet to be found. In the case of teleutospores, however, there are numerous species which produce them alone, and in such cases, all the other spore-forms are considered to have been suppressed or never formed. And of these surviving teleutospores, in some species they are able to germinate at once, and thus produce successive generations in the course of a year, while in others they can only do so after a winter’s rest, and are thus pro- duced only once a year. In the heteroecious rusts there is no evidence to show that the sporidiola can infect the plant bearing the teleutospores, hence it would appear that P. graminis in Australia can only be propagated, as far as spores are con- cerned, by means of the uredospores. It has not been definitely proved how the sporidiola are distributed, but no doubt the wind is an important factor, and probably also animals assist in the distribution. In connexion with the teleutospores of Gymnosporangium, Plowright? says :—* It is prob- able that the promycelial spores are implanted upon the ovary by insects which had previously visited the Podisoma under the delusion that it was a flower, and carried the minute spores with them to the hawthorn.’ The wind, however, is likely to be the common agency. Since the leaves and stalks bearing the germinating teleutospores often lie upon the ground, it might seem at first sight as if they were not favorably situated for the wind to act upon them, but as they are usually, produced in large numbers, suffi- cient of the sporidiola are likely to be suspended in the air to infect fresh plants when the conditions are suitable. How long the sporidiola retain their germinating power, and how far they © can stand drying up, are questions not yet satisfactorily determined. i — wa Paraphyses. =) CHAPTER X. PARAPHYSES AND THEIR FUNCTION. Paraphyses are variously shaped—often hair-like, or capitate unicellular bodies, sometimes accompanying the spores, and are just branches of the hyphae not concerned in, but accessory to, reproduction. These sterile fila- ments may occur in the spermogonia, where they assume the form of stiff hairs projecting from the mouth, and possibly serve to retain the spermatia until they are carried away and distributed by insects. But it is in the uredo-layer that they are most commonly met with, and there they are of various shapes. They are recorded in Australian species of Puccinia, Phragmidium, Melampsora, and in Uromyces phyllodiorum, and along with other characters may be useful in the discrimination of species, as in Puccinia magnusiana, Koern., where they at once distinguish it from the other species occurring on Phragmites communis. They usually surround and arch over the spore-bed, and the apex is often swollen in a globose or clavate manner. Their principal function is probably the same as that of the hairs in some grasses and other plants—to protect the spores when exposed by the rupture of the cuticle against excessive evaporation and consequent drying up during the day, and to moderate the temperature in the cold nights. In the genus Melampsora and some species of Puccinia and Uredo, ¢.g., the uredo of P. poarum, P. magnusiana, and U. spyridii growing on hosts in damp situations or along rivers and in moist valleys, the paraphyses have always swollen capitate heads, and their function is suggested by their structure and position. The wall is much thickened, so as to leave a very small cavity in the head, and in the stalk it may become so thick as completely to obliterate the cavity and thus render it solid. The thickened head has a great capacity for retaining moisture, and since they are crowded together and over-lap the spores, they will prevent them from getting soaked and at the same time protect them against excessive evapora- tion, which would have a drying effect according to Dietel?. Their great function is as protective organs when the spores are exposed by the rupture of the cuticle, and Plowright compares them with the pseudoperidial cells of the aecidiospores. He has made observations on the paraphyses of certain species, and found that their presence greatly depends upon some special condition of the fungus. ‘‘I find them con- stantly present with the uredospores of Puccinia perplexans, Plow., when these have arisen, not directly, but rather at a considerable distance from the aecidiospores. On the other hand, when the uredo arises directly from the aecidiospore, they are hardly present at all; this looks very much as if they were an indication of exhaustion of vital energy on the part of the fungus, which was combated by protective efforts on the part of the parasite in conserving those spores which it does produce, but when full of vigour and fresh from the aecidiospore it is less careful of its spores. When it begins to feel the effect of exhaustion, and is unable to develop such energetic spores, it takes more care of those which are produced.”’ Or it may be that when the fungus begins to feel exhausted, it is unable to develop so many spores, and barren protective filaments take the place of those which would normally produce spores. If the paraphyses serve to prevent excessive evaporation, then it would follow that in the early spring, when there is little need for protection on this account, there would be little use for them; but towards the summer, when the air is 30 Paraphyses. dry, they would be required in much larger numbers. The presence or absence of paraphyses at different periods of the year seems to have been only definitely observed in this one species, but there are other instances which may possibly belong to the same category. Thus Winter describes Uromyces dactylidis Otth. with capitate thickened paraphyses, and Plow- right distinctly states that they are absent, and this discrepancy may arise - from the observations having been made at different seasons of the year. Again, Puccinia poarum Niels. is without paraphyses, according to Plow- right ; but Schroeter found them in Germany, and I have found numerous long ones in Australia. In P. magnusiana Koern. the clavate paraphyses are of a dark smoky brown colour in the head and hyaline in the stalk. They only occur at the margin of the uredo-layer, and there is a slight indentation on the inner side, so that the head bends over. In Phragmi- dium subcorticium the tubular, thin walled paraphyses are always mar- ginal both in the uredo- and aecidio-spore generation, and are curved inwards. Another function has been suggested by Magnus ® in addition to that of protection. In several species of Coleosporium he found that the paraphyses served both for protection and for raising and bursting the epidermis so as to make room for the growing spores. To a certain extent paraphyses may assist in raising the cuticle and hastening its rupture; but there are plenty of species which rupture the cuticle in the absence of paraphyses, and in the case of paraphyses asso- ciated with teleutospores, they rather appear to prevent the cuticle break- ing away until it decays. Origin of Spore-forms, a CHAPTER XI. ORIGIN OF THE PRINCIPAL SPORE-FORMS. The most characteristic feature of the Uredineae and that which renders them specially interesting is the variety of spore-forms which they pro- duce. But while on the one hand there is a regular succession of spore- forms, on the other the number may be reduced even to a single kind, and the question arises in such cases whether the missing spore-forms have dropped out of the course of development, or whether they have never been iormed. Since, as we shall see, there is every reason to believe that the various spores originated from a primitive form, the natural conclusion would be that where they do not occur they have not yet been developed, yet there are cases where intermediate forms may have been suppressed, judging by what obtains in closely allied species. In all rusts whose complete development is known there is one kind of spore which is invariably present, and which serves to distinguish the various genera, and that is the teleutospore. But the teleutospore on germination gives rise to another kind of spore, the sporidiolum, which may be regarded as the starting-point of the life-cycle, just as the teleuto- spore is the last-formed or finishing spore. The simplest form of spore, using this term in its widest sense, was at first developed from any joint of the exposed hyphal filament, but ulti- mately as the differentiation between the vegetative and reproductive por- tions of the fungus became more marked, the point of origin was restricted to a definite spot of an upright hypha—towards the apex. By a process of abstriction, the end of the hypha was rounded off and detached by simple contraction without the formation of any septum. These might either be produced solitary or several formed in succession, constituting a chain. (Fige? a,b.) e UA Fic. 7. The spore might also originate by budding, as in the case of the Yeasts, where a small protuberance quickly grows to its full size, becomes rounded off, and detaches itself. In this process of budding the pro- tuberance often narrows itself at the point of attachment into a slender stalk, whereby the connexion with the parent cell is maintained until the spore is fully formed. (Fig. 8.) Fic. 8. This short delicate stalk proceeding from the parent cell is known as a sterigma, and either by abstriction or budding the origin of the various spore-forms may be explained. 3 Origin of Spore-forms. SPORIDIOLUM. The sporidiolum was probably the earliest form of rust spore, and represents the transition from the saprophytic to the parasitic mode of life. If we start from undoubted saprophytes, the passage from the one to the other will be made clear. It was not only necessary for the spread of these fungi that the spores should germinate rapidly, but that they should be produced in sufficient numbers, and so the basidium, or parent cell, had either to produce more than one spore or divide up into several cells. In accordance with this, in one type, the one-celled basidium produces mostly four spores (Fig. 9); in another type the basidium divides usually finto Fie. 9. four cells, each cell producing a spore. The latter type is well seen in the Auriculariaceae where in such a genus as Saccoblastia the basidia are transversely septate, and each cell bears a sterigma with its spore (Fig. 10). Fig. 10. Turning now to a parasitic genus such as Coleosporium, there is a close resemblance in the mode of formation of spores. |The body called the teleutospore is found to consist of four cells’ placed one above the other, and each cell gives rise to a sterigma, with a sporidiolum at the end of it (Fig. 11). This is something very different from the typical teleutospore, Fig. 11. in which each cell produces, not an ordinary undivided germ-tube, but a gromycelium divided into four cells, each of which bears a sterigma with a sporidiolum. The so-called teleutospore of Coleosporium is evidently the representative of the septate basidium in the Auriculariaceae, although it is generally considered to be an exceptional form of teleutospore, which occurs in other genera of Rusts as well, such as Ochropsora, Trichopsora, and Chrysopsora. If the basidia in one of the saprophytic Auriculariaceae, such as Saccoblastia ovispora Moell., are compared with those of the parasitic Coleosporium senecionis, there is seen to be complete agreement in the structure. Origin of Spore-forms. 33 The sporidiolum was thus at first the product of a basidium arising from a mycelium, but there was nothing specially characteristic in this, nor any advance upon the mode of reproduction in a saprophytic fungus. That which constituted the Rusts a distinct class, and separated them from their nearest allies, was the development of a new kind of spore, the teleutospore, which produced directly on germination, without the intervention of any mycelium, a basidium bearing sporidiola. In the one case the sporidiola were derived from a basidium borne by a mycelium nourished on dead or decaying matter ; in the other the basidium, or so-called promycelium, was the direct product of a living spore. This spore is the special feature of this group of parasitic fungi, and will now be considered. TELEUTOSPORE. In the sporidiolum the fungus is provided with a spore capable of germinating at once and reproducing the original form, but a parasitic fungus requires further to accommodate itself to the varying seasons of ‘grewth of the host-plant, and so a spore that could persist during the winter while vegetative activity was practically suspended, became a neces- sity. Hence the teleutospore, or typical resting-spore, was introduced into the cycle to provide a thick-walled form, which could withstand the vicis- situdes of climate and be ready to germinate when spring, with its revival of growth, returned. While some teleutospores are capable of immediate germination, the great majority undergo a period of rest, and a thickening of the wall is associated with this condition. ¢ While the sporidiolum was thus probably the earliest-formed rust spore, it did not meet all the requirements of the new mode of life, and thus the teleutospore became a necessity for parasitic life, a condition dependent on the changes of a living organism. The great feature of a teleutospore is the mode of germination and its product, and perhaps the simplest form is represented by that of Barclayella Diet., in which there are several cells in a row, and each cell produces a promycelium or septate germ-tube. The peculiarity and primitiveness of this promycelium lies in the fact that, instead of dividing transversely and each cell giving rise to a sporidiolum, the promycelium itself breaks up into four divisions, each of which becomes a sporidiolum (Fig. 12). Fie. 12. The only species belonging to this genus occurs on a Conifer (Picea morinda Link) in the Himalayas, and neither uredospores nor aecidiospores are known. It produces the most primitive form of teleutospore, and the geim-tube produced from each cell breaks up directly into sporidiola, which again reproduce the fungus. This is an evident contrivance for multiply- ing the spore-form (teleutospore) and providing a fresh start with a sporidiolum, minute, light, and easily transported by the wind. The next advance in the development of the teleutospore may be seen in an interesting genus, just described by Arthur®, to which he has given the name of Baeodromus. It occurs on Senecio, and resembles Coleosporium 34 Origin of Spore-forms. senecionis so much in general appearance, that it was at first regarded as that species, but the teleutospore produces a regular promycelium, with sterigmata and sporidiola, so that it well illustrates the transition from the basidia bearing sterigmata in Coleosporium to the typical teleutospore with a promycelium. The teleutospores are united into a solid mass, and are arranged in chains consisting of 5-8 cells in a series, and while Arthur considers each cell as a teleutospore, the chain of cells might be regarded as a multicellular teleutospore. The spores germinate immediately, and the promycelia, together with the four globose sporidiola, have bright orange contents (Fig. 13). Closely related to this form is Chrysomyxa, in Fig. 15. which the teleutospore consists of a series of cells, and on germination pro- duces promycelia of several cells, each of which bears a sterigma with sporidiolum. In A/elampsora the unicellular teleutospores form a compact mass, producing promycelia of the typical form, and thus a teleutospore may either consist of a simple cell or a series of superposed cells. A teleutospore is thus a unicellular or multicellular spore, producing on germination a promycelium, which either directly breaks up into usually four sporidiola or divides into four cells, each of which produces a sporidiolum at the apex of a sterigma. There is one exception to this in the genus “ndophyllum, in which the promycelium is the product of an aecidiospore, but this may be regarded as a case where the function of a teleutospore has been transferred to a derivative form, the aecidiospore. UREDOSPORE. The view that the uredospore is probably derived from the teleutospore is favoured by the variability of the latter in many species, and the grada- tions which are found to occur. At first sight the differences between the uredo and teleutospore seem so great as to be insurmountable, but there are distinct transitional forms from the one to the other. The membrane of the typical uredospore is covered with spines, and this is an evident adaptation for the spore which germinates immediately and is short-lived, and the characteristic spines serve to attach it to the surface of the host-plant in order that germination may be successfully accomplished. Magnus ?, who inclines to the view that the uredospores have developed out of teleuto- spores, shows that in Uromyces scutellatus (Schrank), Lev., a gradation can be traced between the reticulate or tuberculate membrane of the teleutospore and the finely tuberculate or echinulate membrane of the uredo- spore. ; As to the thinning of the wall, there is also every gradation to be met with from the thick brown membrane to the thin, almost colourless one. The passage from the one to the other possibly took place through such a form as the amphispore, a modified uredospore still capable of undergoing a period of rest, and in which the wall still retains its thickness, but there are several germ-pores. They may resemble the uredospores in shape, Origin of Spore-forms. 35 echinulation, and germ-pores, but still they are resting-spores with thick- ened walls. Fischer! has also illustrated the transition in a series of two- celled teleutospores of Gymmnosporangium confusum, which have all ger- minated, and which show a dense thick membrane at one end of the series and an excessively fine one at the other. And Dietel? has pointed out that the occurrence of thick and thin-walled spores in species of Gymmno- sporangium is quite common, and that it is a character of the genus that the teleutospores formed in the interior of the gelatinous mass are thin- walled, while the external ones are thick-walled. The gelatinous substance is formed from the gelatinous walls of the stalks of the teleutospore, and readily absorbs the rain-water and thus facilitates the germination of the spore. Another’ important difference between the uredospore and teleuto- spore of Uromyces is that while the latter only possesses one germ-pore, the former has two or more often arranged as an equatorial band. But here again Magnus shows in species such as U. proéminens (DC.) Pass. and U. tuberculatus, Fckl., every transition from the normal teleutospore with apical germ-pore, through one with the germ-pore becoming somewhat lateral, then with apical and lateral germ-pores, until the typical uredospore is reached with a band of germ-pores confined to the equator, or several scattered. In Puccinia podolepidis there is often a germ-pore on either side of the upper cell of the teleutospore, as shown in Pl. XXIX., Fig. 257. A third and very important difference between the uredospore and teleutospore lies in the mode of germination. Not only does the uredospore germinate im- mediately on maturity, but it puts forth a germ-tube which penetrates directly into the host-plant, while the teleutospore often undergoes a period of rest and does not directly reproduce the fungus, but gives rise to a Piomycelium bearing promycelial spores, which germinate and enter a host-plant. It would appear at first sight as if this mode of germination created a distinct barrier between the two kinds of spore, but when closely looked into there is considerable variation in the germination of the teleuto- spore, and under certain conditions it may forego the production of inter- mediate spores. Kienitz-Gerlofft has shown that in Gymnosporangium clavariaeforme, Jacq., the thin-walled teleutospores do not produce a promycelium and promycelial spores, but simply a germ-tube like that of a uredospore. And Dietel? has further shown that both thick and thin-walled spores may sometimes germinate in this way, and thus serve the purpose of the uredo- spore occurring in other genera. Fischer! has also pointed out the influence of external conditions on the mode of germination, the sporidiola only being formed in air, while in water or in the interior of the gelatinous mass surrounding the spores, an elongated germ-tube is formed. This has been corroborated by Blackman?, who found that the germ-tube is incapable of sporidiola formation when submerged, and that under these conditions it continues to grow in length until its reserve material is exhausted. He also found that when germ-tubes of Phragmidium rubi-were produced in water, they might become divided into four cells, as if about to bear sporidiola, but these cells, instead of following the ordinary course, rounded themselves off and separated. Fischer observed in Gymnosporangium confusum that the cells of the promycelium separated before forming sterig- mata and promycelial spores, but Blackman, in a MS. note to his paper, kindly sent to me, says: “ These are the cells of the promycelium which are rounding themselves off and becoming directly sporidia.”” So that there appears to be every gradation in the germination of the teleutospore. from the production of a simple germ-tube to the division of the germ-tube into cells which germinate, and. finally the promycelium bearing promvycelial 36 Origin of Spore-forms. spores. It is worthy of mention that Magnus? has repeatedly obse1ved that when the teleutospores of Puccinia graminis were germinated in water they produced an undivided germ-tube just like that of a uredospore, but he could not satisfactorily settle the question, if this germ-tube could directly penetrate the host-plant. The passage from a thick to a thin wall, from one to a number ot germ-pores, and from a typical promycelium to am ordinary germ-tube, has been shown, and it all tends to support the view that the uredospore may have been derived from a teleutospore. This peculiar germination of the teleutospore, in which ¢ach promy- celium breaks up into three or four detached cells, apparently representing sporidiola, had been observed by Barclay ? as early as 1891, in Puccinia prainiana, Barcl., and Uromyces solidaginis, Niessl. He considered this abnormal mode of germination to be due to the restricted supply of air obtained by the spores in a hanging drop of water, for, when allowed to germinate in a watch-glass of water, with freer access of air, the germina- tion was normal. But this rounding off of the promycelial cells may be due to the influ- ence of micro-organisms in the water. So far as our own observations go, certain organisms are always present in great abundance when this rounding off of the cells occurs. A similar phenomenon is observed in connexion with the hyphae of numerous fungi growing in water or fluids invaded by bacteria. In another respect the uredospores show a distinct transition. In a well-developed spore-layer they always precede the associated teleutospores, but in Uromyces scutellatus, as Magnus? has repeatedly observed, in different years they may appear simultaneously. . The uredospores may thus be regarded as having been derived from the teleutospores, or from a mycelium common to both, and the question naturally arises as to the origin of the aecidiospores. AECIDIOSPORES. Aecidiospores and uredospores are often so much alike that they are mistaken for each other, and sometimes there is a difference of opinion as to whether a spore-form should Le regarded as one or the other, as in Triphragmium ulmariae ; but, generally speaking, aecidiospores are produced in chains, and uredospores singly on evident pedicels. In Coleosporium and Chrysomyxa, however, the uredospores are developed in chains as well as the aecidiospores, and this renders necessary the further distinction that the aecidiospore always precedes the uredospovre in point of time. In Phragnudium subcorticium, for instance, the aecidiospores were not recognised at first as distinct from the uredospores, but although the indi- vidual spores resemble each other closely, the fact that one is produced in chains and the other not, distinguishes them. When aecidiospores are pro- duced without any special envelope or pseudo-peridium, as it is called, it is distinguished from the Aecidium proper as a Caeoma, and there is every gradation from naked to covered aecidia. In Chrysomyxa the uredo is re- garded as a caeoma-form by Raciborski but in Phragmidium the aecidio- spores are protected by a dense layer of paraphyses, which surround them, and thus take the place of a peridium. TZviphragmium ulmariae (Schum.) Link, has what are called primary and secondary uredospores, although the former are described by De Toni as aecidiospores, but they are not pro- cuced in chains. Winter regards them as biological representatives of the aecidium, and Drs. Milesi and ‘Traverso! speak of them as epiteospores, to distinguish them from caeomospores, which are arranged in chains. There | | =e ee Origin of Spore-forms. 37 is no essential point of distinction between aecidiospores and uredospores, for though the former are always formed in chains, yet undoubted uredo- spores may also be thus produced. Hence there is no valid distinction between the two, even to the matter of nuclei, for both are binucleate. The aecidiospore is just like the uredospore, thin-walled, and adapted for immediate germination ; but since it is essentially a spring form, and required to keep pace with the rapid growth which then takes place, it is not formed solitary upon a stalk, but tier upon tier, to make abundant provision for the coming season. It is usually uredospores and aecidio- spores which are confounded together, but there is one case at least in which the aecidiospore partakes of the character of a teleutospore. In Endophyllum the spores are produced in chains, and within a pseudo- peridium just like normal aecidia, but instead of germinating in the usual way, each one produces a four-celled promycelium, giving rise to promy- celial spores just like a teleutospore. They may either be described as aecidiospores which produce promycelia or as teleutospores resembling aeci- diospores. This genus is not now generally regarded as independent, but as related biologically to Uromyces or Puccinia, and it will probably turn out to be a case where an aecidiospore still retains marks of its early origin from a teleutospore in its mode of germination. (Note 4, p. 75.) SPERMOGONIA AND SPERMATIA. If the aecidiospores were the result of a sexual process, as is some- times maintained, then of course they could not be derived from teleuto- spores, and the mere fact that I have attempted to account for their origin from this source shows that some other explanation must be forthcoming for the so-called male sexual organs—spermogonia and spermatia. In lichen-fungi such as a Collema a true process of conjugation occurs, and the male organ or spermogonium, with its contained spermatia, resembles very closely in structure the similarly named bodies in the rusts. It was Tulasne who originally discovered these bodies in 1851, and who suggested their sexual nature, which he based partly on the fact that the spermatia were not known then to germinate, and partly that they usually preceded or accompanied the bodies they were supposed to fertilize, viz., the aecidia. Great attertion has, therefore, been paid to the spermatia, in order to discover if they were capable of germination, and it has Leen found that in a nutritive solution they grow and bud after the manner of yeast, but no definite mycelium has been produced. It is generally stated that the spermogonia either precede or accompany the aecidia, but they may occur with all the spore forms, according to the one which is first produced. Aecidia usually follow the germination of the sporidiola, and therefore spermogonia accompany them most frequently ; but if the first formed spore is the uredo, as in 77iphragimium ulmariae, Uromy- cladium maritimum, and Puccinia obtegens (Lk.) Tul., then they accompany it, and if a teleutospore as in P. liliacearum, Duby, or Uromycladium tep- perianunt, the spermogonia are associated with it. But Arthur? states the case more generally when he remarks that ‘‘ every one who has made cultures of the rusts knows that in about a week after sowing the germinating teleu- tospores there will appear spermogonia, without any regard to the kind of spore that is to follow.’’ There are even instances w here the spermogonium has entirely disappeared, as in Puccinia malvacearum, Mont. It is ac- knowledged by those who have given special attention to the subject that the spermogonium is an isolated organ, of uncertain origin and function, and that the balance of evidence is against its being a sexual organ. The spermogonium is seldom absent from the life-cycle, and yet it takes no direct 38 Origin of Spore-forms. part in the reproduction of the fungus. Its meaning seems to have been lost, but its origin from the sporidiolum seems to indicate that it may be the survival of the conidial reproduction of the sporidiolum. Unless in cases where the mycelium is perennial, the sporidiolum ger- minates and produces a mycelium, which gives rise to the spermogonium. The same mycelium may either produce aecidia, as is usually the case, or in the absence of aecidia, uredospores; or, if both are absent, the teleuto- spores, as in Uromycladium tepperianum. The spermogonia are never pro- duced alone, but always precede or accompany some other spore form, for the very good reason that they are incapable of reproducing the fungus. When the spermogonium is about to be formed, the hyphae become inter- woven, and form a tangled mass in ‘the sub-epidermal tissues. [rom this numerous delicate branches are given off, which are directed towards the epidermis. These branches converge towards a central point and form a somewhat round or piriform body, which is only covered by the cuticle at the top. The periphery of this body consists of a dense felted mass of sterile hyphae, quite unlike the peridium of the aecidia, which are likewise always deeper-seated than the spermogonia. The so-called spermatia arise inside the spermogonia in short chains by a process of abstriction at the end of fertile converging hyphae, and are held together by a gelatinous sub- stance which contains a certain amount of saccharine matter. (Pl. XXIII., Fig. 203.) The probable origin of this puzzling body may thus be accounted for: We may suppose that the sporidiola were spread principally by wind and rain, and at first only produced teleutospores. But in order to secure the intervention of insects which were now becoming adapted to the floral world, a new kind of reproductive body was developed, and the sper- matia abstricted in chains were produced in spermogonia with a sweet bait to attract insects. But when the teleutospores gradually developed uredospores and the same mycelium could produce the three spore-forms— spermatia, teleuto, and uredo spores—then the former became less and less necessary. When finally the aecidiospores were developed, produced in great abundance, and also in chains, then the competition was too keen, and the necessity for spermatia practically ceased to exist, since the germinat- ing sporidiola could produce the aecidia, and the germinating aecidia both the uredospores and tthe teleutospores. Besides, the bright colour of the uredo and aecidio spores may serve to attract insects for purposes of distribution, and so they were able completely to replace the spermatia. Finally, the spermatia lost their capacity for germination, and now the spermogonium is an organ which has survived its function, and only remains as a land- mark to show what once had been the prevailing type of reproductive body adapted for distribution by insect life. We can thus picture to ourselves the progenitors of the rusts leading a saprophytic existence and gradually adapting themselves to the new mode of life when the parasitic habit was developed and a modification in the spore-forms occurred. The evidence of this great change is shown in the development of a spore primarily adapted for undergoing a period of rest, and from the stored-up material directly producing a basidium with sporidiola, instead of being preceded by a more or less scattered mycelium. The peculiarity of the teleutospore lies in the fact that it is an in- dependent body capable of giving rise directly and without any further food supply to fresh spores by the production of a septate germ-tube, which develops secondary spores unlike the original, being smaller, thin- walled, and ready to germinate at once on the damp surface of a living leaf. In course of time the teleutospores became differentiated into forms adapted for extremes of temperature and resting, as well as other forms Origin of Spore-forms. 39 adapted for favorable conditions and rapid dissemination of the species— uredospores. The third form of spore would probably be developed later in point of time. The aecidiospores were at first just like the uredospores, only produced tier upon tier as required, and the great purpose served by all these different kinds of spores would be to provide a continuous succes- sion of spore-forms—aecidiospores in the early spring, when the first rush of growth commences ; then wredospores during spring and summer, when steady growth is maintained ; and finally z¢elewtospores towards the autumn, capable of remaining dormant during the winter and starting the whole series again in the spring by means of promyycelial spores. The so-called spermogonium does not enter functionally into the present cycle, being a relic of the past and a survival of the time when insects were being catered for by the rust-fungi in order to aid in the distribution of their spores ; but the development of such numerous and varied bright- coloured spore-forms has rendered unnecessary this special form of fructi fication. VARIABILITY OF TELEUTOSPORES. When the teleutospores in the different genera of rusts are carefully examined, it is often found that there is not only considerable variation in the size and shape, but the seemingly constant character of the number of cells is departed from. It is not always convenient to record this in a systematic description, and I have selected a few species to give an indi- cation of what is not at all uncommon throughout the Uredineae (Pl. XL.). This variability not only shows how the uredospore in each genus might have been derived from the teleutospore, but also how the multicellular form of spore might have originated from the unicellular. Starting with the genus Uromyces, there is no difficulty in showing how the bicellular spore of Puccinia may have originated as in Uromyces orchidearum, U. tricorynes, and U. vesiculosus (Pls. XVI., XVIII., XL.) Then in the genus Puccinia there is not only the unicellular teleutospore or mesospore to indicate its pro- bable origin from the Uromyces, but in addition to the two-celled spore there are three and four celled spores, in which the cells are arranged in a manner suggestive of various genera. The different forms seen in a single preparation of P. dichondrae Mont. are shown in Plate XL., and there are at least seven forms met with—(z) the unicellular spore, or mesospore, generally with thickened apex, and resembling the uppermost cell of the next form; (2) the typical bicellular teleutospore; (3) the three or four- celled spore, with the cells arranged in linear series, superposed more or less regularly, and after the Phragmidium type; (4) a three-celled spore, consisting of one basal cell supporting two longitudinally divided on top, and resembling the 77iphragmium type; (5) a three-celled spore, consisting of two basal cells longitudinally divided and a single cell on top, as in Hapalophragmium; (6) a four-celled spore with the two lower superim- posed, and the two upper longitudinally divided ; (7) a four-celled ellipsoid spore longitudinally and transversely divided, as in Sphaerophragmium. It is worthy of note tthat there are no uredospores in P. dichondrae, but, even in P. ludwigit, where uredospores are present, there is also a con- siderable amount of variation. A two-celled spore is met with here, having the septum longitudinal instead of transverse, and the pedicel in a line with it, as in Diorchidium. PP. graminis and P. triticina also show a Considerable amount of variation, if large quantities of material are examined. Other genera exhibit variation of a similar kind, and there is a basis here provided for natural selection to work upon, ‘and evolve the various forms which are used to characterize the different genera of the Uredines. 40 Relation of Rusts to other Fungi. CHAPTER XII. RuUSTS IN THEIR RELATION TO OTHER FUNGI. The Fungi, as a class, are generally regarded as having descended from the Algae, but since the latter possess the green colouring matter or chlorophyll which enables them in the presence of sunlight to abstract carbon from the carbon dioxide of the air, they do not seem to be the most primitive forms. But the fission-fungi, such as the nitrifying bac- teria occurring in the soil, are able, in the absence of light and chloro- phyll, to split up carbon dioxide and obtain the necessary carbon likewise from inorganic material, so that the first forms of life to appear upon the earth could thus obtain their nourishment without organic compounds at all. The development of the chlorophyll would thus occur at a later period, and the fungi proper, as well as the algae, may have had a common origin from these primitive bacteria, instead of the one being a degenerate form of the other. Following the fate of the fungi, with which we are more immediately concerned, their course of development ran parallel with that of the algae, so much so that they have been regarded as degenerate algae or algae without chlorophyll. This primitive stock resembling the algae so closely is known as Phycomycetes, and from this divergence has taken place in two directions, the offshoots representing two main divisions of fungi. In the one case the Ascomycetes or fungi producing spores in delicate sacs or asci, and in the other, the Basidiomycetes or fungi producing naked spores on large terminal cells known as basidia. To this latter division belong the Uredines or rusts, since they produce basidia which are trans- versely divided, and bear naked spores; but they occupy a low position as compared with the higher Basidiomycetes, including the mushrooms and toadstools. In the Ustilagines or smuts closely related to the rusts, the basidia are not as yet definitely fixed, since the spores are produced at any part and new ones are developed when the old ones fall away, which is not the case in the rusts. The following arrangement will show the position of the rusts in this scheme of classification :— Fungi. Ascomycetes ( Hemibasidii (Smuts) Basidiomycetes + Protobasidii (Rusts) | Bolobasidii (Mushrooms, &c.) Phycomycetes (Alga-like Fungi) Starting from the Phycomycetes or alga-like fungi, there is one divi- sion of them which bears both sporangia and naked spores, and another in which the sporangia may be wanting. The former would give rise to the Ascomycetes, and the latter to the Basidiomycetes, which exclusively reproduce themselves by naked spores. The smuts are generally regarded as stepping-stones from the Phycomy- cetes towards the rusts, which have become more closely identified with the true Basidiomycetes, where the basidia are entire and not divided. The above gives a very general idea of the position of the rusts among the fungi, and indicates briefly, without entering into detail, how they may have originated. The parasitic habit of the rusts will account for several features in their life-history as well as in their structure. Being dependent on other Relation of Rusts to other Fungi. 4I plants for their sustenance, they must accommodate themselves to their surroundings, and so they may pass through different stages, sometimes on the same plant, or on different plants. These various stages represented by different reproductive bodies, enable the rust to produce spores which can germinate at once if food supplies are available, or others which can rest if need be. The change of host is an evident advantage, not only from the point of view of a change of diet, but it may thus pass from one plant that dies down to another that is perennial. It may even become perennial itself in the underground parts of some plants, and then it vegetates, only producing rarely the reproductive bodies which would be formed under normal conditions. 42 Indigenous and Introduced Species. CHAPTER XIII. INDIGENOUS AND INTRODUCED SPECIES. In a large continent like Australia, where so many plants have been: introduced, both for economic and ornamental purposes, it is not always easy to determine what rust-fungi are native to the country, and those that have been introduced on imported plants. A plant may be indigenous, and yet the rust upon it may have been derived from an allied species, as in the case of P. thuemeni on native celery (Apium prostratum) which was possibly introduced with cultivated celery (Apiwm graveolens), P. menthae on native mint introduced upon cultivated mint, and Melampsora lini, om native and cultivated flax. On the other hand, species of rust occur on well-known imported plants, such as the daisy, groundsel, and marigold, which are not recorded elsewhere, and the natural conclusion is that they are indigenous, or have been overlooked elsewhere. _ It is only in rare cases that the first introduction of any species of fungus is observed and accurately determined, so that we must fall back upon some well recognised principle to settle whether a rust is indigenous or not. Where a new species is found on a native plant, it may be taken for granted that it is indigenous, and even where the species is already known, but the plant has a wide distribution, such as Phragmites communis, then there is no reason to doubt that a rust upon it, such as Puccinia magnusiana is also indigenous. The great majority of the rusts here recorded are, of course, native, and it will only be necessary to single out those which have, in all probability, been imported from other countries. The following species may be regarded as having been introduced on the grounds indicated* :— Puccinia anthoxanthi Fckl. on Anthoxanthum odoratum (1896). . arenariae (Schum.), Sckroet. on Stellaria media (1896). beckmanniae n. sp. on Beckmannia erucaeformis (1904). . chrysanthemi Roze, on Chrysanthemum indicum (1904). . cichorii (DC.) Bell., on Cichorium intybus (1885). . cyani (Schleich.) Pass. on Centaurea ‘cyanus (1904). . festucae Plowr. on Festuca pratensis (1903). . graminis Pers. on Wheat, &c. (1825). . helianthi Schwein. on Helianthus annuus (1887). . hypochoeridis Oud. on Hypochoeris radicata (1889). . Impatientis (Schw.) Arthur, on Elymus condensatus (1903). . loli Niels. on Lolium perenne (1896). . malvacearum Mont. on Malva, &c. (1857). . maydis Bereng. on Maize (1880). . menthae Pers, on Mentha laxiflora (1884). . poarum Niels. on Poa annua (1890). . prenanthis (Pers.), Lindr. on Lactuca sp. (1892). . pruni Pers. on Prunus sp. (1883). . purpurea Cooke, on Sorghum halepense and S. vulgare (1892). . simplex (Koern.), Eriks. and Henn. on Barley (1902). . thuemeni (Thuem.) McAlp. on Apium graveolens and A. pros- tratum (1892). . triticina Eriks. on Wheat (probably 1825). Uromyces appendiculatus (Pers.), Link, on Vigna catjang (1905). U. betae (Pers.), Kuehn, on Beta vulgaris (1878). a9, rg PS 6 oe oe ee ng bo ed * The year in brackets indicates when first recorded for or observed in Australia’ Indigenous and Introduced Species. 43 U. caryophyllinus (Schrank), Schroet. on Carnations (1896). U. fabae (Pers.), De By. on Beans (1898). U. polygoni (Pers.), Fckl. on Polygonum aviculare (1896). U. trifolii Alb. and Schw. on Trifolium repens (1892). Phragmidium subcorticium (Schrank), Wint. on Rosa sp. (1892). Melampsora lini (Pers.), Tul. on Linum usitatissimum and L. marginale (1889). Uredo kuehnii Krueg. on Sugar-cane (1893). It would be interesting to trace from what quarter these species found their way into Australia, but from the very nature of the case, it is impossible to tell exactly, except in a few instances, and one can only make shrewd guesses as to the rest. The inquiry would mainly resolve itself into the importation of the host-plants, either by cuttings or seed, and the seed of such weeds as chick-weed (Stellaria media) and knot-weed (Poly- gonum aviculare) might easily be carried in straw packing or in hay. Mr. Ellery, F.R.S., late Government Astronomer, has pointed out that the scarlet pimpernel (Azagallis arvensis) was first observed as an intro- duced weed in the Observatory grounds, and he informs me that as many English and African plants appeared there at different times after unpack- ing cases from the different countries, he came to the conclusion that seeds from the packing were the source. Both uredo and teleutospores of Puccinia graminis have been found on wheat straw envelopes on bottles of wine imported from France.—(Note 5, p. 75.) In the case of the cereals and grasses, the rust spores would probably be brought with the seed, and this is certainly true as regards Puccinia beckmanniae. ‘The seed of Beckmannia erucaeformis Host. was forwarded to me in 1903 by the United States Department of Agriculture, and on growing it at Leongatha, the rust was very copiously developed in February and March, 1904. EE. D. Holway informs me that it is known in Minnesota, U.S.A., although it has not hitherto been published. The seed of Elymus condensatus was also sent from America in 1903, and the rust (Puccinia impatientis) appeared upon the plants in December of the same year. The latest addition to our imported rust-fungi is that of Puccinia chrysanthemi, and it was observed for the first time in New South Wales in 1904. Cuttings had been imported from England, and thus the rust was carried ; but it has not as yet spread very much. Only the uredospores occur kere as in England, and I was able to germinate them freely in tap-water towards the end of May. It is by means of this trade in cuttings that the rust is likely to be spread, unless proper precautions are taken. The history of its distribution is rather interesting. It is pro- bably indigenous to Japan, and in 1895 it first appeared in England, then in France in 1897, and about the same time in Denmark and Germany. In 1900 it reached America and Switzerland, and now, in 1904, or earlier, it has come to Australia, probably by way of England. It was also re- corded for New Zealand in 1904. The mallow rust (Pxucctnia malvacearum) has been known in Australia since 1857, when it was found in the neighbourhood of Melbourne, and now it is one of the commonest rusts we have. It is remarkable for the rapidity of its spread, nearly over the whole world, since it was first de- scribed in 1852 from Chili, where it is indigenous. After its appearance in Australia, the next record of it is in Spain (1869), then France (1872), England and Germany (1873), Italy (1874), Switzerland and Cape of Good Hope (1875), Austria and Hungary (1876), Greece (1877), North America (1886), Sweden (1887), and even reaching Finland (1890). 44 Indigenous and Introduced Species. The hollyhocks on which this rust occurs are ornamental plants, and the disease may have been spread in the ordinary course of trade or exchange. The first record of a rust is by no means a guide to its first appearance, for it 1s generally only when it has become established and has proved injurious that it attracts attention. The prune rust, Puccinia pruni, which now occurs in all the States, was first observed in Queensland in 1886, and was recorded for Victoria in 1883. Although con- fined at first to certain districts, it has since then spread considerably, and as settlement increases it becomes more widespread. The flax rust, Melampsora lini, was first determined on some cultivated flax from South Australia in 1889 by Galloway of the Bureau of Plant Industry, U.S.A. Bolley, in a letter dated 29th December, 1904, informs me that it is a very abundant rust upon all the wild varieties, and is always more or less destructive in the flax crop. It is common enough here on the native flax, and was probably introduced with flax seed. There are four species of Phragmidium in Australia a genus confined to the Rose family, and only one of them is supposed to have been intro- duced. Phr. subcorticium only occurs on the imported genus Rosa, and was probably introduced in rose cuttings, since the mycelium of the aecidium is known to winter in the stem. Phr. potentillae on species of Acaena was determined by Winter, and although referred by him to this widely distributed species, it is probably new. Phr. longissimum was first discovered at the Cape of Good Hope, and is now known to occur in other parts of Africa. Its appearance on a native Rubus in Queensland would seem to support the generally accepted opinion of a former land-connexion between Africa and Australia. But Wallace in his /sland Life offers an alternative view. ‘‘ We should prefer to consider the few genera [of plants] common to Australia and South Africa as remnants of an ancient vegetation, once spread over the Northern Hemisphere, driven southward by the pressure of more specialised types and now finding refuge in these two widely separated southern lands.”’ From the shape and arrangement of the teleutospores and their germination immediately on ripening, this species stands apart from the others belonging to this genus, and Dietel 1° draws the conclusion that it separated at a very early period from the common stem of the genus Phragmidium, a conclusion which harmonizes with the views of Wallace. But the most interesting case of distribution is that of Phr. barnardi, which is not confined to Australia as was formerly believed. Quite the same type has now been found in Japan on the same host-plant (Rubus parvifolius), and, according to Dietel}°, it is simply a variety of the Aus- tralian species, having fewer cells in the teleutospore, and therefore dis- tinguished as variety pauciloculare. A number of plants are common to Eastern Asia and Australia, and R. parvifolius is included by the late Baron von Mueller in a list of plants which extend from Eastern Australia to Japan. There are various ways in which the species may have attained to its present wide distribution, which is given as Malaya, China, Japan, and Australia. Birds may have carried the seeds, and with it some attached spores of the fungus to the Asiatic continent, or inversely from Japan to Australia. There is also the possibility of a former land-connexion between Australia and Asia, which is assumed by the zoologists, and at that time the two forms of Phr. bar- nardi may have existed. The flora of Japan, like that of Australia, is regarded as being of the same character as that of the Tertiary period, so that the wild raspberry and allied plants had plenty of time to spread from a point to the north of both Australia and Japan, carrying with them to their new homes, the rusts already developed upon them. Indigenous Species with their Hosts. 45 CHAPTER XIV. INDIGENOUS SPECIES WITH THEIR HOosTs. The great majority of Australian rusts complete their life-history on one and the same plant, and are thus autoecious ; but, although heteroecism, or the division of the life cycle into two generations, each on different host- plants, has not yet been proved for any of them, still it has been so well established for several in other countries, that we may accept it for the present as likely to hold good here. As to the recognised indigenous species which are also heteroecious, there are only four—Puccinia agropyri, P. agrostidis, P. magnusiana, and P. caricis—the three former on Gramineae having their aecidial stage on Ranunculaceae, and the latter on Cyperaceae with its aecidial stage on Urticaceae. If we arrange the indigenous species of rusts known in Australia under the different families of their host-plants, which are further classified ac- cording to their predominance, as determined by the late Baron von Mueller (Table) some interesting deductions may be made; but it must always be remembered that the number of known species is probably far short of those actually existing. | Under these circumstances our conclusions can only be partial, still, even with these limitations, it will be instructive to compare the predominance of the native host-plants with that of the native rusts. It is found that the greatest number of rust-species occurs on the families of native plants which are large in point of numbers. Thus the Leguminosae with the greatest number of species have eighteen different rusts, while the Compositae, which only stand fourth in the list, have seventeen. At the same time it ought to be noted that future discoveries may alter this rela- tion. for no less than seven species of the new genus, Uromycladium, have been added to the Leguminosae within tthe last few years. The 'Cyperaceae, which succeed the Compositae, have only four species, while the Gramineae, which come next, have thirteen species. Then the Liliaceae have seven species and the Rubiaceae five ; but on the remaining families they vary from one to five. The Leguminosae and Compositae have eighteen and seventeen species respectively, the Gramineae coming third with thirteen species. The grasses and composites are gene- rally herbaceous, quick-growing plants, with succulent leaves, and the rust-fungi can most readily penetrate their tissues and secure during the growing season sufficiency of food. They would also be guided in their choice by the chemotactic nature of the substances contained in the host- plants ; but there are so many factors which enter into the choice of a host- plant by a rust that we can only mainly at present note their preferences. Confining our attention now to the species of Puccinia alone and compar- ing them with the numbers and distribution as given in Sydow’s Mono- graph, it is found that while one-fourth of all the species inhabit Com- positae and one-eighth occur in Gramineae, so with the native Puccinias in Australia more than one-seventh belong to the Compositae and _ one- ninth to the Gramineae. In the Leguminosae only one species has been met with, and only fifteen. species are recorded altogether. tr Hosts. th the 7és WI Indigenous Spec Tsopou-Idis -9 avoruodel ~srprdoro +9 srueplq “p vuliedsosue -q vnprred «9 avoRIssog -9 *“oduya AVLIR9IO * sujsAo0u0ul - youoqurAo - aa soprorioond +4 ovryorsyoy} “1, UINAvapyo10 *— SIpIyOsoTar fy signomuoe} * avqyIVYyAyo * avImoyjuEp * [Bp Toprv90ws gy vURIBsIS “A eviolduep “gq ovmouniq «q Wodde} -g SUdqTUqns “f suvxe[died *[ SUGISNUSeUL 7 SIPUSOSOARY “7 styuopouAd -g Ov0Rd “g eulmo1q “q SIPIYSOIBe “gq WAdOISR -g AULIOJIUaTOS * Trqoy Aged * tunemInge - “WOlIAY ada e10ds1suo[ +g wed -g S[OlIvd -q OVIUTPVIFLA “I eOTURUISey *q stprdojopod «gq evllea[O “qd avloydouese “gq IOUMAIGUayTVy *q Teydeus -q SIggqoe10 -gq SIPTZOTVO * Teydaoo[evo -q samtooAyoriq “q evloljsnsuy “gq “VNOUVO “VuUOSAINY TAI | aevmmosyoul -9 tunurieddsy -19 xo] duis -19 WOSUIqOI “IQ. aTIqvzou *If) TUNUIGIVU “1 umnaz0dstq -19, wanurdye -19 winiorpo][ Aud - avisrlaquepity - sniodsisny - sngourigq * i-)-J=1=) aviuioz -g | “WOLLUVNOUD “WOIdINDVUHd “"WAIGVTOAKOUN “SHOANOUD “VINIDONd —ovoovtmepooy —avapryoro —oveuruivin —avoovledsp —orysodmog —ovaorejolg — o¥sourmnsey ‘SEISOH WAILVN NO SHIONdS SQONHSIGNI dO WIAVL 47 Indigenous Species with their Hosts. BlOOTYIUBAOT ‘d SBIMODVI4O4 Ms muAd0dv “9 upudds juossnur “al eqjone OBSSTIVO OvIXA[L ‘d ‘d ‘d aBIOJIONIO ‘d Wopowsey ‘d OVITUOIOA “VW OULIOJIOSIp “¥ avi puoysIp ‘d ovyTosouly, *—) awiq1eqqiy ‘d ovIposeyl “f evioul -ULVYTOYOS *() lisaydouoyies *Q oveyMsue “—) ORIDULIVOp “VW TWPITAys ‘d ‘sIpHysoLo;dyp a tuaauoAjod +) avIsoyjuex 1yguerseyld vrodsoraqay ‘d ‘d ‘d ovoid “y spudnge -p aRIyooy ‘d VURIS[OIP ° d ov[niodse * sou dtodd *— srurqind -/) aviaemMoido avygjuesiyo avoquIma * ‘d xe! avlisoldoo * d d aviIpxleyomaq -q STUOTLO4SONa * @Rod100 avTUo10g d ‘d ‘d —avoovVYJURIOT —oveplooliy —avoovyjuroy —oaroorfnuedwue,) —oroorudsv0dy —arvioyonig —avaoRLopowmlor }{ — 0B00R[NA[OAUO/) Roo vdemMydorog —dIROIVUTIRY AT — ovoovIUoT IG —d¥vOdRIPI[AIS —ovoovpuldeg —ovooRqueleuly — ovo Toqu p —dOROOVATRTY —arvoorlpodousyy) _—ovaoviqny — ovary —ovoovny Indigenous Species with their Hosts. whoo TUNQRUTULOSSIp “VW —-MeddAy “WW a’ ORVIIVA -sTuisequeid “Vy 103 -B1994-11q O19 * overtly “1 TWOSTIIOUL «J 1so[td-1uwdes «gq evooviopoy “d eiodsmuo} *q eirydoounl -g ov -[iguejod «gq twunut -ISSIBUOT *q Iprvuseq -_ 103 -¢ a euelpezjuid “gq wunie -9ORTNOUNUVI “Ww sIp 9VYZVI VW -euapa “pO | siprxoday “qd ; ; SNSO[NOISAA *-Q stproydmAu -y ia aa evrjoaq -ueTyonur *q snqijod “9 TSIM pul “gd Tyguvdalos “9 Aa Ee “WaTdIOay “YNOAVO ‘yuosdnvtTain | ‘walluyNouo | ‘walauvevund | ‘WaIaVIOAWOUN | ‘“SHaOAWOUn *VINIOOOd —avoovouedAH —ovarvUlsvyur[ —ova0BIZBuO —ovoov[nsstdy —avoovlUB1as) —anaoujorA —araovoune —avaousoy —dva0vIpurmMaly, —avaounounuey —aveoepl [Albury —aroorAydos {47 —aoovuriquary —avaonuo0s A[og —ervooryAydoAiey “panurjuoo—SLsOP[ TAILVN NO Saloddg SNONGDIGNT JO ATAVY, Indigenous Species with their Hosts. 49 It is worthy of remark that on some of our most predominant families, such as Myrtaceae and Proteaceae, which are only exceeded by the Legu- minosae, the rusts are practically absent. It is passing strange that upon our numerous Eucalypts and kindred species not a single rust-fungus should have developed, while in the Proteaceae, with their wonderful variety of foliage, only a single species, and that a Uredo, is recorded. Melamp- sora eucalypti Rabh. found in Calcutta on the leaves of Eucalyptus globulus is merely a name, and the specimens show no indications of a rust. Ihave carefully examined the original specimen in Rabenhorst’s Fungi europaei 2592, and while the leaves have numerous blister-like swellings over them, they are found to consist of discoloured cells, the epidermal cells parti- cularly being brown and discoloured, and might superficially be mistaken for spores. In the preceding table only indigenous rusts are given which occur on native host-plants, but such rusts may either be confined exclusively to native plants or they may occur on other allied introduced plants growing here as well. Thus Puccinia tasmanica is found on the introduced weed the common groundsel (Senecio vulgaris), but one stage of it is also found on native species of the same genus, and, therefore, it is regarded as in- digenous. The rust may also be found on native plants, though in other parts of the world on allied species, and yet be regarded as native, as in the case of P. perflexans and P. agropyri. There are even cases where native rusts, or at least rusts not known elsewhere, are confined exclusively to imported plants, as P. calendulae, P. cinerariae, and P. distincta. As regards introduced rusts, they may be found on both native and imported plants, the presumption being ithat the rust spread from one to the other, though some may incline to the view that these are as much natives of Australia as of any other country. Disregarding Puccinta graminis, there are four such species, P. menthae, P. malvace- arum, P. thuemeni, and Melampsora lini. There is still another group consisting of introduced rusts found here on imported plants alone, such as Puccinia chrysanthemi and Phragmidium subcorticium. 50 Australian Distribution. CHAPTER XY. AUSTRALIAN DISTRIBUTION. It would be premature to attempt to arrange the Australian rusts in geographical districts, since they are as yet too imperfectly known, and large areas have not been explored sufficiently to give any exact idea as to the number of species or the distribution of those already known. So for the present I will content myself with indicating their distribution in the different States, and this may lead to a filling up of many of the gaps, when it is seen what species may exist in one State, and are probably to be found in some of the others. There is one evident way in which our knowledge of this group might be extended and the area of distribution made better known. They depend for their existence on the occurrence of suitable host-plants, and since these are given for each species, as far as known, wherever the host-plants are to be found, there the parasites might be looked for. The total number of species at present recorded is 161, and they are distributed among the different genera as follows :— 1905. 1892. Uromyces ace 27 35 13 Uromycladium ... 7 is) — Puccinia ae 90 ae 24 Phragmidium 4 4 Cronartium I I Melampsora 2 3 Roestelia _ I Caeoma BA 2 Bat ° Aecidium a es ne 16 Uredo 14 10 161 72 It will be seen that the Puccinias constitute more than one-half of the whole, and the Uromyces come mext. In Cooke’s Handbook of Australian Fungi, published in 1892, there are only 72 recorded, or less than half the number, and even some of these do not stand the test of further investigation. In J/elampsora, for instance, there are three species given, and two of these must be withdrawn, one belonging to another species also recorded, and another not being a rust at all. And in Sydow’s Menograph, just completed for the Puccinias, only 43 are given for Australia. The following list shows the distribution of species in the different States, and it is naturally very unequal. In Victoria, which heads the list, there has been a zealous band of collectors stimulated into activity by the late Baron von Mueller and encouraged by a progressive and active Field Naturalists’ Club. In Queensland the Government Botanist has always been most enthusiastic in working up the Fungi generally, and in New . South Wales and Tasmania good progress is being made. Although South Australia does not possess an official Government Botanist, that State is fortunate in having such a zealous Botanist as J. G. O. Tepper, F.L.S., Australian Distribution, 51 who has given special attention to this group, and has not only described some species himself, but has had several mamed in his honour, such as Puccima teppert and Uromycladium tepperianum. - a eo Victoria. Ree eouin Queensland. Aas | Peas | Tasmania. Uromyces ... 27 21 12 7 6 ade 6 Uromycladium 7 7 3 I 2 I 6 Puccinia ae go 69 26 14 re Io 28 Phragmidium .. 4 3 I Bayh Wh 2 Cronartium ... I I I BS ae I Melampsora ...| 2 2 I “he I tee | I Caeoma sae 2 1 2g nl Aecidium eon ES 9 5 3m) Ail I 7 Uredo ... eee ekg 5 3 4 I 2 Totals aco ||) Gr 118 50 33 27 13 53 52 Parasitism. CHAPTER XVI. Tur ORIGIN AND SPECIALISATION OF PARASITISM. In a group of parasitic fungi like the rusts the question naturally arises, How did this parasitic habit originate? Parasitism in fungi is an adapta- tion whereby the fungus can directly draw its nourishment from the living material, and in order to do this it must have become accustomed to a new mode of life, for it is assumed that originally the fungi obtained the requisite substances for food from dead or decaying organic material. The saprophytic mode of life seems to have led up to the parasitic, for there is every sort of gradation between the two. Some parasites are able to complete their development entirely on artificial nutritive media. Others require to infect the living plant first, and then undergo their final develop- ment on dead tissue, while others begin their life on dead material, as a preparatory stage to passing over to the living substance. The origin of parasitism and that of specialisation are so intimately bound up that they may be conveniently considered together, for at the critical moment, when the spore first put forth its germ-tube into the living tissue of a particular host-plant and was able to grow there, then parasit- ism was established, and if the fungus confined itself to that host then specialisation had begun. What induced the fungus to enter the living plant by means of its germ-tube, and afterwards confine itself to one or a few closely-allied species is the question to be answered. It does not seem difficult to account for the entrance of the germ-tube into the stoma, for it follows the lines of junction of the cells, and ultimately comes to a stoma, into which it dips just as it would into any other opening. But to be able to penetrate the cells and abstract nourishment from them is the point which requires explanation. It is assumed that the saprophytic habit was the normal one among fungi, and that parasitism is an acquired habit. Massee® claims to have proved this assumption to be a fact, for he says—“ A saprophytic fungus can be gradually educated to become an active parasite to a given host- plant, by means of introducing a substance positively chemotactic to the fungus into the tissues of the host. By similar means a parasitic fungus can be induced to become parasitic on a new host.” Parasitism, then, is due to chemotaxis, which is a form of sensitiveness in the plant whereby it has an affinity for certain substances, and is opposed to others. Thus there are various substances which are capable of attracting or repelling the germ- tubes of fungi, and the name of positive or negative chemotaxis has been given to this property. In an extensive series of experiments conducted with both parasitic and saprophytic fungi, Massee® has shown that certain substances in the plant are positively chemotactic in their nature, and others negatively so. Thus it was found that sugar is the most general of positive chemotactic sub- stances, although its action on the germ-tubes of obligate parasites is very slight. | Experiments showed that “it was not sufficiently powerful in any instance to attract the germ-tubes through perforations in mica or through stomata.”’ Specialisation of Parasitism. Recent investigations in connexion with heteroecious rust-fungi, or those which change their hosts and produce a different kind of fungus on each Parasitism. 53 host, together with the results of infection experiments, have considerably modified our views as to the limits of species in such fungi. Eriksson!, in dealing, with cereal rusts particularly, found that they were not liable to ‘infect indiscriminately the different cereals, but were confined to one, or, at most, a few closely-allied host-plants, and to this phenomenon, so widespread among parasitic fungi, he applied the appro- priate name of specialisation. As examples of specialisation among heteroecious rust-fungi may be given those of Puccinia coronata, Corda, and P. graminis, Pers. Klebahn! proved by infection experiments that the crown rust on Dactylis glomerata and other grasses only produced its aecidium on /7vangula alnus, while that on Lolium perenne required for its aecidial host Rhamnus cathartica, Hence the old species was split up into two, which can also be separated by mor- phological characters. Eriksson! also proved in 1894 that the well- known and much-investigated species of Puccinia graminis could be split up into a series of forms, all of which agreed in producing aecidia on the barberry, but differed in the uredo and teleutospore generations, only being able to infect special host-plants. Puccinia dispersa, Eriks., was proved to be an independent species, with uredo and teleutospores on rye, and its aecidia on species of Anchusa. Included in this were a number of forms which had no known aecidial stage, and they were afterwards separated and raised to specific rank as P. ¢riticina, P. bromina, P. agropyrina, &c. If a general view be taken of this phenomenon it is found that when two closely-related species, say, A and B, are attacked by a rust-fungus, the one on A will not infect B, and that on B will not infect A, even although the two fungi are the same species, regarded from a morphological point of view. ‘There must, however, be some adaptation between the host and the fungus, so that the latter is attracted towards the one host and repelled by the other. But it kas been shown by Ward! that occasionally a spore from A may gain a footing on B, and once. having done this it can continue to infect B, since it has now become adapted to it. According to the same observer, parasites may be educated to attack fresh plants by means of what he calls bridging-species. Thus, while the parasite on A may be unable to infect B, it may be able easily to infect a related species C, and after establishing itself on C it may then have the power to infect B, so that C becomes the bridging species from A to B. Massee® has also shown that a parasitic fungus can be led to attack a new host- plant by injecting a Substance positively. chemotactic to the fungus into the tissues of the living leaf. Parasitism is thus an acquired habit, and, generally speaking, it be- comes specialised, because only in certain plants are the substances present which attract the fungi, while in others there are also certain substances which repel, and thus prevent their germ-tubes gaining a footing in the tissues. But in contrast to this specialisation, there occurs in a few species what may be called general parasitism, where the parasitic fungus is able to in- fect host- plants widely separated in their affinities. ‘Fischer? and Klebahn! have shown that Cronartium asclepiadeum can attack plants belonging to such distantly related families as Ranunculaceae and Scrophu- lariaceae, as well as Asclepiadeae, so that it has become necessary to unite under this name, species which were formerly separated on account of the difference of host-plant. Chemotaxis can hardly be held accountable for such a widely-divergent distribution of host-plants, and although it does not clear the matter up, it may be referred to the ‘‘ internal developmental tendencies’’ of Klebahn ! eel a better explanation is forthcoming. 54 Parasitism. The specialisation of parasitism resulting in the evolution of biologic forms is not confined to the Uredineae, but probably extends to parasitic fungi generally, which frequent more than one host, and this has been experimentally proved, particularly in the mildews or Erysiphaceae. Seve- tal biologic forms may occur within a morphological species, so that it will be necessary in the future, for the proper understanding of any such species, not only to determine its limits by means of structural characters, but also the special forms included in it with restricted powers of infec- tion. Hitherto it has been generally assumed that the same parasitic fungus occurring on two closely related host-plants would be mutually infective, hut this does not necessarily follow, even with different species of the same genus. Neger!, in 1902, proved by numerous experiments that there were biologic forms of Oidium for several species of Evysiphe, and Marcha]? in the same year divided the one species of E. graminis into seven distinct forms, using only the conidia for purposes of infection. He showed that the biological form on barley was unable to infect wheat, oats, and rye, and Salmon2 carried the experiments a stage further by using the asco- spores, which had the same restricted powers of infection. This difference in infective power is not due to any apparent structural change in the fungus, for the form of E. graminis on the wheat is indis- tinguishable, even under the microscope, from that on the barley, and yet the form on barley cannot infect the wheat, nor can that on wheat infect the barley. The difference, therefore, lies in the physiological peculiarities of the host-plant, and it has been suggested that the cells of the leaf contain an enzyme which is fatal to the growth of the haustorium of any other form. But probably the action is reciprocal, and the germ-tube of the fungus finds something in the particular host-plant which attracts it, and is conducive to its growth. Heteroecism. 55 CHAPTER XVII. HETEROECISM AND ITS ORIGIN. In a great many species the various stages of the self-same fungus, as already indicated, occur on the same host-plant, but the variety in the mode of reproduction has also brought about a variation in the mode of nutrition, for there are a number of species in which one part of their life is passed upon one species of plant, and the remainder on a totally different species. ‘The host-plants are not even related to each other, but stand far apart in their natural affinities. Those which passed their entire existence on one plant have been called awtoecious species, while those which spread it over different plants are called heteroecious species. As a general rule it is assumed that the different forms of rust occur- ring on the same host-plant are genetically connected, although it is always desirable, where possible, to have experimental proof of it. In Uromyces polygonit, for instance, the three stages of aecidio, uredo. and _ teleuto- spores may all occur together on the same leaf, or the aecidia may occur on one portion of the plant, and the uredo and teleuto sori on another ; and in both cases the species is regarded as having three stages, which are different forms of the same fungus. It is but a step further to have, say, the aecidia on one host-plant and the uredo and teleuto stages on another. and this affords a greater variety of food supply. Just as in the separa- tion of the sexes in flowering plants, we are justified in assuming that all the different stages occurred at first on the same host-plant, but gradually, in the struggle for existence, one reproductive body matured on one plant and the others on a different plant, so that a change of food was secured and a succession of crops insured. This heteroecism of the rusts was first discovered by De Bary in 1864, when he proved that the rust in wheat, Puccinta graminis, produced its uredo and teleutospores on the Gramineae, while its aecidial stage developed on the barberry. It has thus been assumed that heteroecious species originated from autoecious species in the simple and seemingly natural way that the two generations separated, just to occupy fresh ground, at first passing over to nearly allied plants, and gradually to plants further and further re- moved in the natural system, until the present position of affairs was brought about that the two generations of the same fungus attack plants widely removed from each other, as far as their natural affinities are concerned. But there is no evidence to prove that such a gradual separation took place, for even although the species of Pweccinia on Phalaris may have their related aecidia on other Monocotyledons, and the Uromyces on the pea, with its aecidia on a Euphorbia, yet they are always considerably remote from each other. Im fact, the view that heteroecism originated suddenly and without the different generations slowly and gradually pass- ing from plant to plant, seems to have most in its favour. It is admittedly a difficult problem, since from the very nature of the case no one has been able to observe an autoecious fungus becoming heteroecious. Heteroecism is only possible when more than one spore-form occurs in the life-cycle, and how the variety of spore-forms originated is capable of different interpretation. It may either have been a progressive develop- ment from the simplest forms, or it may have been a retrogression from the most highly developed forms. We may conceive heteroecism to have 438. C 56 [eteroecism. proceeded from the formation of teleutospores being succeeded by aecidio- spores, presumably at first both arising from the same mycelium. Next a division of labour took place, and the mycelium of the aecidia was pro- duced by the sporidiola, while the mycelium of the teleutospore proceeded from the aecidiospore. ‘The advance to heteroecism took place when the aecidiospores produced their mycelium in one host-plant and the teleuto- spores, through the sporidiola, in another, and the kernel of the matter lies in the answer to the question, How did this come about? It may either have taken place by a long series of slow and gradual changes, whereby the different spore-fonms gradually accustomed themselves to the new mode of life, or it may have developed suddenly by one of the spore-forms germinating and growing on a different host-plant, and continuing to do so. But this latter view is hardly borne out by some experiments conducted by Miss Gibson!, in which the aecidia from different host-plants were used to infect Ranunculus ficaria, and while the germ-tube as a rule entered the stoma freely, it was generally dead and shrivelled by the third day. This result was not supposed to be due to starvation, for she says:-— ‘‘ Whether the incapacity to penetrate the cells is due to lack of attractive substance or to the presence of ianything actively repellent is not clear, though, as before stated, certain facts seem to suggest the presence of something harmful to the hyphae.”’ A few concrete examples may be given to show how far these views are borne out by facts. De Bary considered the probable origin of three species of Chrysomyxa occurring in the Alps, and the relation existing between them :—C. rho- codendri (DC.) De Bary, forms its uredo and teleutospores on species of Rhododendron, while its aecidiospores occur on Picea excelsa, the name given tto this form before its connexion was discovered being Aecidium abietinum, Alb. and Schw. C. ledi (Alb. and Schw.) De Bary, forms uredo and teleutospores on Ledum palustre, and its aecidia also on Picea excelsa, there being little or no distinction between them and those of C. rhododendri. The third, C. abzetis (Wallr.) Ung., forms the same kind of teleutospore on Picea excelsa, but the sporidiola from the germ-tube produce mycelia which only form teleutospores and no aecidia or uredo- spores have been observed. In seeking to account for this, he assumes a common origin of the three forms, and considers that either the original form from which they were all derived had no aecidial fructification to start with, or there was an aecidial fructification, and C. abdbietis has in course of time dropped it. The latter view is the one he favours. We can imagine these three forms competing for Picea as an aecidial host, and while two succeeded in establishing themselves, the third, C. @dzetis, was compelled to drop it altogether. Barclay’, in tracing the developmental history of Uredineae, attempted to show that in the struggle for existence, heteroecism was beneficial, and that if two species compete against one another for a host, that which makes for heteroecism will more probably succeed than that which makes for autoecism. There is another interesting series of forms worthy of consideration known as ‘‘ coronate’’ rusts, because the apex of the teleutospore is pro- longed into and crowned by a number of finger-like processes. There are both heteroecious and autoecious species as follows :— P. coronata, Corda, I. Frangula alnus, II., III., Grasses, r. 2. P. lolii, Niels., I. Rhamnus cathartica, &c., II., III., Grasses. 3. P. himalayensis (Barcl.), Diet. I. R. dahurica, II., III., Grasses. Heteroecism. ey . festucae, Plow., I. Lonicera periclymenium, &c., II., III., er Grasses. 5. P. mesneriana, Thuem. III., Rhamnus alaternus. 6. P. digitata, Ell. and Hark. III., R. croceus. 7. P, schweinfurthii (P. Henn.) Magn. III., R. staddo. 8. P. longirostris, Komarov III., Lonicera hispida. g. Uromyces. phyllodiorum (B. and Br.) McAlp. O., II., III., Acacia notabilis, &c. Fischer considered that the original forms of the heteroecious species lived both on the grasses and Rhamnus as autoecious fungi, and that they could undergo their complete development on either of them. These original forms were thus supposed to be able to live on a variety of hosts, and it is assumed thatt only in recent times had they become specialised. In support of this view there is a rust—Puccinia graminella which produces both aecidia and teleutospores on a grass, and I have also found an aecidium on Danthonia, and although teleutospores were not observed on the same plant, I still regard the two as belonging to the same species, viz., Uromyces danthoniae. Fischer presupposes that the original form was both autoecious and plurivorous, and it is reasonable to suppose that a fungus which could live upon two such distinct hosts as Rhamnus and grasses would, at the same time, select numerous other plants as hosts, so that this view hardly explains the fact. JIit is much simpler to suppose that since these primary forms had begun to form aecidia and eventually uredospores, they no longer carried out their complete development on their original hosts, since a change of host was in a sense equivalent to a cross in flowering plants. They accord- ingly changed their teleutospores (and uredospores) to new hosts, so that the autoecious stage was dispensed with because it was not so advantageous as the other. This change of host is not a haphazard affair, but takes place according to a definite plan. It may be confined to a single or a few distinct species, and attempts to bring it about on plants which do not belong to the regular cycle, as a rule, end in failure. But, of course, the regular host plants may fail, owing to drought or some other climatic conditions, and then the fungus often obeys the law of self-preservation, by repeating the same generation again and again. This may even become a fixed habit until the single generation is more or less independent, and then it is all that remains of what was once a complete cycle. Among the heteroecious fungi there is a regular course of development which is usually followed. The one host-plant bears the ‘aecidium genera- tion, and the other host-plant the uredo and teleuto spore generations, but there are slight differences in detail which may be noted here. The complete cycle of development, as already stated in the introduc- tion, is the most common, in which the teleutospores germinate in the spring after a winter’s rest, and produce sporidiola. ‘The sporidiola infect the young leaves of the proper host, and produce aecidia, usually accom- panied or preceded by spermogonia. Then the aecidiospores infect the host which bears the uredo and teleuto spores, but as a rule the regular course of development is interrupted by the repeated production of uredospores before the final stage is reached. The fungus is thus widely spread from plant to plant by means of the uredospores and then the teleutospores are formed in the autumn, either from the same mycelium or from a teleuto- spore-bearing mycelium proceeding from the uredospores. C2 58 Heteroecism, This course of development may be represented graphically as follows, taking P. graminis as the type :— a, in Europe. b, in Australia. Spermatia Teleutospores Sporidiola 4 Uredospores Teleutospores BARBERRY Uredospores (repeated) Aecidiospores Uredospores Fic. 14. Fig. 15. The aecidial stage of the spring rusts of wheat (P. ¢riticina) or barley (P. simplex) is not known, but Klebahn hazards the suggestion that the hosts to which they respectively belong may only exist in their original home, and thus not hitherto observed. Wath such widely and extensively cultivated plants, the uredospores could easily be carried on the grain or by the wind, and the fungus could thus be perpetuated without the intervention of an intermediate host. The tiding over of the winter is most important for those fungi which depend upon two host plants for their continued existence, but while this is usually accomplished by means of the teleutospores, other and additional measures may be taken to secure the same resuli. Sometimes the uredo- mycelium persists during the winter, and in the case of Puccinia arrhenatheri the aecidium-mycelium becomes perennial, and reproduces the aecidia year after year, while the teleutospore is also produced. When the aecidiai stage is dropped, as in thecase of Puccinia graminis in Australia, then there is a profuse development of uredospores in comparison with teleutospores, and there is abundance for present needs, as well as for future germination in the spring. In other cases where ‘the aecidial host is absent, the same thing has been observed, asin Coleosporium senecionis, when occurring in a district destitute of fir trees, or Chrysomyxa rhododendri when the silver fir is absent. Heteroecism is said to increase the vigour of the fungus, and a striking illustration is given by Puccinia graminis on wheat. It is sometimes said that the aecidiospores from barberry are much more virulent than the uredospores derived from the wheat itself, since the teleutospores produced are earlier, more copious, and more injurious to the wheat. With reference to this, Plowright says :—‘‘ There is a wonderful difference in the amount of injury done by mildew, when derived directly from the barberry, and when derived from uredo that has reproduced itself through several gener- ations. . . . The fungus grows with such energy that it so injures the wheat plant as to prevent it producing more than a few starved kernels.’’ As against this view, it may, be well to bear in mind that in no country in the world probably does P. graminis cause as great injury to wheat as it does in Australia, a country with barberries practically non-existent, and in which the aecidial stage has never been found. Of course further observations on a number of species are necessary to establish the fact, but Klebahn considers that the utilization of the vegetative periods and other peculiarities of the host-plants, rendered pos- sible by the change of hosts, gives the fungus a decided advantage. Heteroecism. 59 Whatever view we take as to the cause of heteroecism, it is a well- established fact that the promycelial spores, no matter how freely applied, produce no effect om the grasses which bear them, and the most probable theory as to its origin assumes that the uredo and teleuto spore generation were at first associated with the aecidia, but ultimately passed over to other hosts. 60 Predisposition. CHAPTER XVIII. PREDISPOSITION. Wherever epidemic diseases caused by parasitic fungi occur, the ques- tion is raised as to the relative susceptibility of different varieties or indi- viduals. The fungus has the power of causing disease in the host plant attacked, but the latter in its turn may either be favorably or unfavor- ably disposed towards its development. This predisposition of the host for the attacks of the parasite is very variable, and is influenced by vari- ous factors. It is generally considered that a sickly plant is more liable to rust than a sound one ; but, on the contrary, strong and sound individuals are more easily and more virulently attacked, so that for artificial infection strong-growing plants are selected. Ward’ has shown that when the host- plant is starved by withholding certain mineral salts, and thus stunted in wrowth and generally enfeebled, it is not affected in its susceptibility or otherwise. A starved plant certainly develops smaller pustules and fewer spores on account of the diminished supplies of food available for the mycelium, \but the power of infection is just as great as in normal plants. As far as brome rust is concerned—and we have no reason to doubt that it holds good for others as well—predisposition and immunity on the part of the host, and impotence and virulence on the part of the parasite are alike independent of mere nutrition. But, as we shall see afterwards, certain substances not of the nature of food-material, introduced imto the plant may affect its liability to disease. There are various factors, how- ever, which may either dispose the plant towards disease or tend to render it immune, and some of these may be given here. The age of the part attacked has an important influence on infection, particularly where the sporidiola are concerned. Young leaves and shoots are most easily infected, and when they get older little or no effect is pro- duced. This is owing to the germ-tube of the sporidiolum penetrating the epidermis direct, and it is well known that this layer becomes firmer and tougher and less easily penetrable as it gets older. The uredospores and aecidiospores, on the other hand, infect the older leaves as well as the younger, and this is easity explained from the fact that their germ-tubes enter through the stomata. Different parts of the same plant are also variously affected. Some- times it is the leaves, sometimes leaf and stem, and it may be on one or both sides of the leaf. The different species of rust on the same host- plant are apt to choose different portions. Thus Puccinia triticina, from its earlier attack, is found most commonly on the lower leaves, and extends on to the sheath, mostly near its junction with the leaf, while P. graminis is worse on the upper leaves, and often parficularly bad on sheath and stem. Different varieties or sorts of the same species vary considerably in their susceptibility, and, as will be shown later, it is by the selection and breeding of such rust-resistant sorts that solution of the rust-in-wheat ques- tion in Australia is being attempted. The same is the case with other rusts, and I have seen one kind of flax (Linum usitatissimum) badly attacked by Melampsora lint, and another kind growing alongside quite free. Hennings® has recently made observations which tend to show that plants previously susceptible to the attacks of a parasitic fungus may gradu- ally become immune when they are changed to rich ground where they are better nourished and more vigorous. Predisposition. 61 In 1894 several rhizomes of Peltandra virginica were sent to him from North America, and planted in pots. An aecidium developed on the stems and midribs of the leaves, which was found to be new and named Aecid- zum importatum. One plant was left in the pot, which was placed in water, and the others were planted out in a soil composed of damp humus. The pot plant has annually produced the aecidia up till the time of writing (1902), while the other plants only showed the fungus very slightly in 1895 and 1896, after which they grew exceedingly strong, and since then have remained perfectly sound. It must be remembered that this is a hardy marsh-loving plant, and there is probably more than mere nutrition concerned in its freedom from disease, since it would be more reasonable to regard the result mentioned as due to the change of situation than to change of soil. Salmon? considers that the evidence which is gradually accumulat- ing on the subject of the relations between host-plants and parasitic fungi leads us to the conclusion that immunity and susceptibility are due to con- stitutional (physiological) peculiarities, and not to any structural ones. He has also shown experimentally that while the uninjured leaf may be im- mune, the same leaf when cut or injured may become Hable to infection, and the conidia produced on such leaves are then able to infect uninjured leaves. In this way the range of infection of a biologic form may be in- creased. Different species of the same genus, when they are generally at- tacked by a rust-fungus, may vary considerably in their susceptibility to infection. If we attempt to explain the varying susceptibility of different plants or different kinds of plants, then the difficulty is apparent, and the sym- biotic relation between the parasite on the one hand, and the host-plant on the other, complicates the matter. Why is the fungus able to infect certain host-plants, and not others? Why is the host-plant capable of resisting certain fungi, and not others? How is the fungus able to accommodate itself to certain plants, and not to others? ‘These and other questions may be asked, but cannot be fully answered at present. De Bary? says :—‘‘The physiological reason for these predispositions cannot, in most cases, be ex- actly stated; but it may be said in general terms to lie in the material composition of the host, and therefore to be indirectly dependent on the nature of its food.” The question has been asked, if there is any relation between liability to infection or power of resistance and the visible structural features of the leaf, and it has been answered differently by various investigators. Hennings” lays stress upon the physical characteristics of the parts of the plant on which the parasitic fungi occur. He considers that the para- site develops differently on a thin-skinned, delicate leaf, and a thick- skinned, firm, leathery leaf. Also that the venation and hairiness of the leaf may affect the result. Marshall Ward! fully investigated the structural peculiarities of the leaves of the various species of Bromus used in his infection experiments with brown rust—such as thickness of cell-wall and cuticle, ‘‘ bloom,”’ size, number, and distribution of hairs, distribution of chlorophyll-tissue and vascular bundles—and he arrived at the conclusion that ‘‘ the resistance to infection of the immune or partially immune species and varieties is not to be referred to observable anatomical or structural peculiarities, but to internal, that is, intra-protoplasmic properties beyond the reach of the microscope.”’ Salmon? comes to the same conclusion from his infection experiments with the oidium of E7ysiphe, but the physical characters of. the wheat-plant seem to have some some effect on its liability to rust, for there are certain 62 Predisposition. > typical characters associated with the quality of rust-resistance, and they would appear therefore to have a share in bringing about this result. In a rust-resistant wheat, the leaves have a tough cuticle, and the straw is well-glazed often with a glaucous bloom. The flag is narrow not broad, erect not drooping, stiff and firm, not soft and flabby. Still all these characters may be present, and yet the climatic conditions may overrule them and weaken the power of rust-resistance. It will thus be seen that a variety of causes may contribute to rendering a plant im- mune, and that not only the chemical and other properties of protoplasm come into play, but there is also the mutual reaction of the living proto- plasm of host and parasite to be considered. As far as the rust fungus is concerned, there is no such thing as a per- fectly immune wheat-plant, for, given the necessary conditions of situation, heat, moisture, and spores at the right season, and at some time or another rust will appear. We express this by saying that there are ‘‘ rust-resistant ” wheats, but not ‘‘ rust-proof.’’ Animals are sometimes rendered immune, or, at least less susceptible to disease, by repeated infections, so that they become gradually accus- tomed to the effects of the parasite, and the important question arises, Can plants also be submitted to “ protective inoculation”? Inoculation with attenuated bacteria is the simplest method with animals, and this treatment retards their vegetative development, and so lessens their injurious effects. This artificially-induced immunity only lasts a certain time, varying, in different cases. Ehrlich and Huebener! have shown, from numerous experiments upon animals, that an immunized mother can impart immunity to her offspring, but it is not lasting. In the case of plants, as in animals, there seem to be two opposing forces at work. On the one hand, the protoplasm of the fungus is endeavouring to overcome the resistance to its entrance offered by the host- plant, while on the other hand the host is more or less successfully resisting the inroads of the fungus. There are no known cases of a plant becoming ‘immune’’ or ‘‘partially immune’’ by inoculation with the parasitic fungus to protect it against further attack, but advantage has been taken of the great sensitiveness of certain spores to copper salts to protect the organism against them.—(Note 6, p. 75.) Chemotaxis is the name given by Pfeffer! to a form of sensitiveness which certain organisms possess towards certain chemical substances. This power, which certain nutritive and other substances have of attracting bacteria and other organisms towards them, is known as ositive chemotaxis, and of organic substances with a high nutritive value which are positively chemotactic, may be mentioned asparagin and peptone, while sugar, which is one of the best food stuffs and richest sources of energy, has but little attractive power. The power of other substances, on the contrary, to repel bacteria, is know as negative chemo- taxis, and free acids and alkalies, as well as alcohol, have this effect. Glycerine, as far as known, is an inactive substance. Massee® has stated that immunity is owing to the absence or small proportion of the substance chemotactic to the parasite in the plant not attacked, and if a plant can be. impregnated with some substance which is negatively chemotactic, and at the same time does not affect the utility of the plant, then immunity against parasitic fungi may be obtained in this way. Laurent!, acting on this principle, conducted a series of experiments to test the possibility of producing potatoes which would be proof against Phytophthora infestans. He grew very susceptible varieties in pots, to the soil of which sulphate of copper was added, and when the tubers were harvested, some were cut in two and their cut surface placed in contact with Predisposition. 63 the mildew of potato leaves. After four days, the tubers grown in the soil containing copper did not show any infection, while those grown in untreated soil were infected in a very decided manner from being brought into contact with a mildewed leaf. Marchal ?, following on the same lines, tried to secure immunity to lettuce against Bremia lactucae, and he found that the plants treated showed considerable resistance, and the immunity seemed to be in proportion to the strength of the solution. He also experimented with cereals for pro- tection against rusts, but without success, and the probability is that he did not use the proper substance which repelled the germ-tubes of the irust- spores when they attempted to enter the plant. Massee’ experimented with cucumber and tomato plants, watering the soil on which they were grown with a solution of sulphate of copper. The result was that “ not a single one of the treated tomato plants showed a trace of disease” after being sprayed with water containing the spores of the fungus, while the untreated check plants were badly diseased. It is important to note that tomatoes produced from plants treated with solutions of copper sulphate were found on analysis to show amounts of copper not sensibly greater than that found in the fruits obtained from un- treated plants. These experiments at least show that certain substances entering into the constitution of the host-plant render it for the time being immune to the attacks of certain fungi, even although it was naturally predisposed to that particular form of disease. 64 Wheat Rust in Australia. CHAPTER XIX. Tue PRESENT POSITION OF THE RUST IN WHEAT QUESTION IN AUSTRALIA. It will tend to clearness if we confine our attention to the rust in wheat, for the general considerations which hold in this case will apply to the rusts on the other cereals chiefly cultivated, viz., oats and barley. And the rust which is most important from the farmer’s point of view, because it does the most damage, will be chosen viz., Puccinia graminis, which is so distinct in its characters that there is no difficulty in recognising, it. There are only two kinds of rust in wheat in Australia, the positively injurious Puccinia graminis and the comparatively harmless P. ¢riticima, because it does not pinch and shrivel the grain like the other. In the early days wheat and other cereals had to be imported into Sydney, but now it is grown to such an extent in the Australian Commonwealth that in the season 1903-4 there were 5,566,340 acres under wheat, yielding a total of 74,149,634 bushels. Wheat will always form one of our staple products, and from the great extent of the industry, whatever increases the yield or tends to diminish the losses from disease, will have a corresponding far-reaching effect. Ever since attention has been given to the subject, it has been found that not a year passes without its being present on wheat to a greater or less extent, and in some years, which are commonly spoken of as rusty years, it seriously injures the grain and considerably diminishes the yield. To give some con- crete idea of the extent of the loss, it may be stated that in a particularly bad season like that of 1889, the loss was estimated to be for the whole of Australia between £2,000,000 and £3,000,000. In such favorable years for the rust, there is always an evident connexion between the weather and its epidemic nature. In 1889 it was a wet spring, and about the blooming season the weather was what was known as “ muggy,” consisting of showers with heat between, and heavy dews, so that the wheat-plant, at the time of coming into flower, was particularly susceptible, and the rust spores found a ready entrance into the tissues of the plant, with their accumulated stores of food, and thus it spread rapidly. Atmospheric conditions are often regarded as the prime factors in the production of rust, but they are only concerned in the matter in so far as they favour or hinder the development of the parasite which causes it, and this is strikingly shown in the existence of rust-resisting wheats. Owing to the importance of the subject, and the widespread losses, delegates from the various States were appointed to meet and confer periodically, and these various conferences extended from the first in 1890 to the last in 1896. The results of their labours may be seen in their voluminous reports, which practically cover the different phases of the question. But there were some Important points with which they were not then in a position to deal, such as the effects of rust on the straw and grain, and experiments in the inocu- lation of the barberry. These will be considered preliminary to the main questian. EFFECTS OF RUST ON THE STRAW AND GRAIN. The visible effects of the rust on the wheat plant is well shown in PI. XLIV., where the straw of the rust-resistant Rerraf is bright, glossy, deep yellow, and well ripened, while that of the badly rusted Queen’s Jubilee has a dirty, streaky, patchy appearance. ‘The ears of the one are full-sized and well formed, with plump, well-filled grain, and the other has poor ears with light and shrivelled grain. Wheat Rust in Australia. 65 But the effect upon the composition of the plant, and particularly its feeding value, is not known to the farmer, who cuts his crop for hay when rust threatens to ruin it. This has recently been determined by F. T. Shutt +, chemist, Dominion Experimental Farms, Canada, who analyzed two samples of wheat grown at Manitoba in the same field and of the same age, only the one was rusted and the other rust free, so that the results are strictly comparable. The analysis is as follows :— ANALYSIS OF Rusted AND RUST-FREE WHEAT-STRAW AND GRAIN, SI | | ae s 2 3 i | = 2 5 Ss) om a i jos Grams. | | | Straw fromrust-free wheat |... 7°92 2°44.) EGS |. 99g'00 39°95 | 9°04 Straw from rusted wheat |... 7°92 GaGgs. |\l et “O7 | 38°44 36°78 | 7°20 Grain from rust-free wheat | 3°0504 | 12°26 Tossa) |i 2966 | 70°55 PPM Mo vinrVE Grain from rusted wheat | 1°4944 | 10°66 13°69 | 2°35 | 68°03 3 2°24. The Strew.—lIt is pointed out that in crude protein the rusted straw is much richer, and since this includes all the nitrogenous compounds of a food that go to repair waste, form blood and build up muscle, it may safely be concluded that the rusted straw is much superior in feeding value. There is also in the rusted straw slightly more fat and somewhat less fibre. so that all this affords additional evidence of its more highly nutritious nature. The handling and feeding of rusty straw in Australia from the farmer’s point of view has received attention. The experience of one who has done a deal of threshing is to the effect that when very bad it caused an itchy sensation, and made the men about the thresher rub their skin until it was broken. As regards feeding rusty hay, another with large experience informs me that horses and cattle relish it far before ordinary hay. Of course, it was fed as chaff. The Grain.—This from the rusted wheat is only about one-half the weight of that from the rust-free wheat, but as the protein content shows, it has, weight for weight, a considerably higher nutritive value. He accounts for the higher protein content in the smaller grain in its larger pro- portion of bran, but chiefly in the partial and incomplete transference and accumulation of starch. These results likewise afford interesting evidence as to the physiological effect of the rust on the wheat plant, and agree with what has been deduced from other data. In the actively growing and feeding period of the plant’s life, it is apparently able to provide for the wants of the fungus as well as its own, and therefore its vitality is not seriously affected. But when the second period of forming and ripening the seed arrives, when feeding is gradually ceasing, and the accumulated materials are being transferred to the seed, then the fungus draws upon the plant’s capital, crippling its energies, and checking the movement of the food materials to the seed. As Shutt sum- marizes the whole process :—‘‘ The growth of the rust arrests development, and indicates premature ripeness, which, as we have seen, means a straw in which still remains the elaborated food, and a grain small, immature, rich in protein and deficient in starch.” This emphasizes what we have frequently insisted on, that the critical period, literally the turning point in the plant’s life, is reached when it 66 Wheat Rust in Australia. begins to form the grain, and if that season is favorable for the develop- ment of rust, then the fungus has to draw upon the stored-up material, and consequently the grain is not fully formed, if at all. Incidentally this investigation also throws light upon the reason why the earlier rust (P. triticina) is comparatively harmless, since its period of greatest activity is when root and leaf are busy manufacturing material sufficient to provide for the necessities of both. On account of the comparatively late appearance of P. graminis, it is by some considered to do the least damage to the grain, but, as a matter of observation, and on physiological grounds, it is known, at least in Aus- tralia, to be the most injurious. Puccinia GRAMINIS AND THE BARBERRY IN AUSTRALIA. In Europe and America the identity of P. graminis is determined, not merely from its morphological characters, but from its ability to infect the barberry and produce aecidia. But in Australia infection of the barberry has not been successful, although several attempts have been made, and some have doubted whether we have got the true P. graminis, and not a distinct biological form of it. From a comparison with European speci- mens and a critical examination of the sori, the uredo and teleuto spores, there is no doubt that the rusts are very much alike, only if the infection of the barberry is accepted as a diagnostic character, then the identity is not proved. ‘The relation of this rust, therefore, to the barberry in Australia became a pressing subject for experiment. The germination of the teleutospores may be easily accomplished at the proper season, either by placing them in a drop of water on a slide under a bell-jar, or, better still, if copious germination is required, by taking some of the rusty straw and placing it on a drop or two of water in a petri dish, the cover of which is lined with damp blotting-paper. It is only after a considerable rest that they will germinate, and they start on warm days about the end of September, which is the beginning of our spring. This may continue through the warmer days of October, almost or entirely ceas- ing in a cold spell, and even until November germination continues if the conditions are favorable; but although numerous trials have been made, no germination has occurred outside these months. Generally speaking, the middle of October is the height of the season for germination, and then, too, the uredospores may be multiplying rapidly on the growing wheat- plant ; so that there is no ‘‘ off ’’ season in Australia, as far as wheat is con- cerned, when the teleutospores are active and the uredospores dormant, In any case, as our wheat crops are usually harvested in November and December, even if the barberry were common, and developed rust freely, it could hardly be of much importance as a factor in spreading the wheat rust, since the aecidia would not be developed profusely before the wheat crop had passed the danger point. The barberry is not a native of Australia, and very few hedges exist, so that the question of its infection is not of great immediate practical im- portance, but it is of high scientific value to establish the fact that the rust may pass one portion of its life on one plant, say, wheat, and continue it on a very different plant as an intermediate host, say, barberry, and thus settle that the rust with which we have to deal is the P. graminis of Europe. As early as October, 1892, I succeeded in germinating the spores freely and copiously in a watch-glass with water, and infected four different species of barberry obtained from the Botanic Gardens, two of which were Wheat Rust in Australia. 67 known elsewhere to carry the aecidial stage of P. graminis. In one case the infected branch was placed under a bell-jar to preserve moist conditions, but there was no result with any of the species, since the weather was too hot and dry. In 1902, in order to give the experiment another trial under the most favorable conditions, Dr. Plowright kindly forwarded several young har- berry bushes from England, which arrived here in December in good con- dition. Rusted straw was specially kept exposed to the weather in order to inoculate the barberries. About 16th September the barberries were putting forth their young leaves, and looked very healthy. One was kept as a check, and the others were infected, either by scattering rusted straw around the plants and tying it on to them, or, in two cases, by applying germinating spores direct to the leaves. Some plants were kept under bell-jars, others exposed, and all were attended to and watered freely. The result was that not the slightest trace of any fungus appeared on any of the barberry leaves. It may be stated that the conditions for fungus growth were most favorable, as at times that muggy heat prevailed, which so quickly spreads the rust in a growing crop. In 1904 the experiments were continued in the pots, partly on the same lines with rusted straw, and partly by planting a rusty wheat beside the barberry, so that it might be naturally infected next season. Cuttings from the English barberries have also been planted at Port Fairy in a rusty spot where they have thriven, and Queen’s Jubilee wheat planted around them produced abundance of P. graminis. The rusted straw was allowed to die down on the spot, and every facility given for the inoculation of the barberry, but without result so far. Some P. graminis on wheat was sent by Dr. Plowright in March, 1903,° which was gathered in September, r902, and kept in his garden till March. On arrival here some of it was kept inside, and a portion placed outside exposed to the weather, just as was done with Australian rusted straw. It was thus . exposed during our winter months of June, July, and August, and in September it was tested, being then exactly twelve months old. While the teleutospores about six months old from the Australian wheat germinated freely, there was no change in the spores from the English wheat, and although attempts were made at different times, there was never any sign of germination. Probably they were kept too long, as they might have germinated on or about the English spring. Prior to this, I had sent rusty Australian straw for trial to Dr. Plowright, but none of the teleuto- spores showed tke slightest trace of germination. Writing in the Gardeners’ Chronicle for 15th January, 1898, he says®:—‘‘I have tried on two occasions to get the teleutospore of Puccinia graminis from Australia to germinate in England, but I have not succeeded. The first attempt was made nine years ago, when Mr. D. McAlpine was good enough to send me material ; but I was quite unsuccessful. Last year he was kind enough to send me a further supply ; but, although I kept the straw out of doors during the latter part of last winter and the spring of 1897, I was equally unsuccessful. Is it probably like the seeds of some of the higher vege- tables, the teleutospores require not only a period of rest, but also an exposure to a certain degree of cold?’ Seeing that the spores germinated freely here, the “exposure to cold” theory does not hold; and the most probable explanation is that they had been kept too long, and attempts to germinate them should have been made in the English autumn. As far as Australia is concerned, the rust which does the principal damage has apparently no intermediate stage. 68 Wheat Rust in Australia. The Australian rust has been determined as Puccinia graminis by Eriksson and other authorities; but if the ability to produce the aecidium on the barberry is taken as the final criterion, then judgment must be suspended in numerous other cases. ‘Thus Massee* has found P. graminis on Alopecurus pratensis, and Avena elatior in the Royal Gardens, _ Kew; but he significantly adds—‘‘ Notwithstanding the great quantity of Berberis and Mahonia present in the grounds, the most careful and con- tinued search has failed to reveal the presence of the aecidiospore stage.” (Note 7, p. 75.) THe PROBLEM STATED. In dealing with the rust question from a practical point of view, there were two main issues to be determined :— 1. How is the rust spread and continued from season to season ? 2. How may its injurious effects be mitigated or counteracted or prevented ? The first question is a most important one, for if we could find out where, and under what conditions, the rust is lying dormant during the time from reaping the crop to sowing it again, then we might be able to destroy it at this stage, and prevent its reappearance. Although the question may thus be simply stated, it is by no means easy to answer. The second subject of prevention or mitigation will evidently depend on our knowledge of the life-history of the rust fungus, as well as of the wheat plant itself, and how far the conditions can be controlled which render it susceptible to the fungus. How the Rust is Spread and Continued from Year to Year.—We know exactly now, thanks to the labours of Eriksson, Marshall Ward, and others, Low the rust-spores enter the plant by means of their germ-tubes, how they grow and ramify among the tissues, and drain them of their contents, until they again form a spore-layer, and reproduce the spores on the surface in great abundance. We thus know how fresh spores orginate once they have got a start; but it is the starting-point which is the difficulty. Although the rust was known, and the effects produced by it were familiar from remote antiquity, yet its true nature was not discovered until the latter half of the eighteenth century. As late as 1733, Jethro Tull, writing about it in his Horse-hoeing Husbandry, attributes it to the attacks of small insects ‘‘ brought, some think, by the East wind, which feed upon the wheat, leaving their excreta as black spots upon the straw, as is shown by the microscope.’’ In 1767, its true nature as a fungus, and therefore as a plant, was determined by Felice Fontana, and in 1797, Persoon gave it the name by which it is still known, Pxuccinia graminis. The rust then is a fungus growing inside the wheat-plant, and living at its expense, and reproducing itself by means of minute seed-like bodies or spores, which are so conspicuous on the leaves and stem of the wheat at certain seasons. For a long time there was a suspicion in the minds of many practical farmers that the barberry bush had something to do with its spread, and so firmly was this believed in, that the State of Massachusetts passed an Act compelling the inhabitants to extirpate barberry bushes. And when De Bary, in 1864, justified the farmer, and proved scientifically that there was a connexion between the fungus which appears on the barberry bush, and that which appears on the wheat, then it was thought by many that we had reached the root of the matter, and that we had simply to destroy the barberry bush in order to get rid of the rust. But it is well Wheat Rust in Australia. 69 known that here in Australia, where barberry bushes are not native, and where they are comparatively scarce, the rust is particularly bad in certain seasons, so that there must be other causes to account for the prevalence of rust. The connexion between wheat-rust and barberry has already been dis- cussed, so need not be further referred to here. There are several possible ways in which the presence of the rust year after year may be accounted for, and it may be worth while to consider some of these. 1. The uredospores produced in such immense numbers may serve to carry it on. They are very minute and light, easily distributed by the wind, and it has been shown that they exist in the air and on the ground. They might thus be readily transported and even carried to localities far removed from wheat- growing areas, in some cases by the duststorms which are very prevalent in the northern parts of Victoria. But the mere presence of spores 1s not sufficient to account for the rust being spread, since they must be capable of germination. I have often tried to germinate uredospores taken from straw that had been left on the ground, but without success. My latest attempt was with uredospores still retaining their colour from a sorus on a dead leaf of Queen’s Jubilee wheat on March 25th. The spores were kept moist under a bell-jar,- but not a single one ger- minated. But the result is difterent when spores are taken from self-sown wheat growing in the interval between the two crops.—(Note 8, p. 75.) 2. These spores are not only in the air and on the ground, but they are commonly to be found entangled in the bearded tip or ‘‘ brush ”’ of the grain. In one variety, Queen’s Jubilee, this was so common that not a single grain could be found without the uredospores. Dr. Cobb! has likewise examined the brush of a number of varieties in New South Wales, and found in about 57 per cent. of the grains examined that the spores were in the brush. This is an evident starting-point for the rust, but not the only one, since seed wheat treated with bluestone. formalin, corrosive sublimate, and other fungicides, produced rusty plants, and in fact there was little difference as regards rust between the plants from treated and untreated seed. 3. It was commonly supposed until recently that the rust could readily pass from one cereal crop to another, and thus it was passed on to the wheat at the proper season. This view was put forward as late as September, 1904, in the /ournal of Agriculture of South Australia, by A. Molineux!, who states :—‘‘I have observed for many years that when ever we have a mild autumn and summer, accompanied with occasional showers, we have complaints of red rust in the succeeding crop ; and I have been led to the belief that until the new wheat crops have started, the rust is nursed by the wild oats and other cereals that may always be found growing on the headlands and by the roadsides.’’ Of course, this is a very convenient way of accounting for the presence of rust throughout the year, but Eriksson has shown that the spores from oats will neither infect wheat nor barley, nor will the spores from the barley infect wheat or oats. It follows from this that adjacent fields of these crops will mot affect or be affected iby each other, so far as this rust is concerned. Probably, however, Molineux’s view is correct, except that it is the self-sown or volunteer wheat growing in our paddocks or on the headlands that carry it over. The system of harvesting practised in Australia with the com- bined harvester, which takes off the heads only and delivers the winnowed grain into bags, necessarily implies the scattering of a certain amount of seed on the ground, and this yerminates with the first rain, and is almost always partly rusted, and often badly so. Our hay being largely made 70 Wheat Rust in Australia. from wheat, when rains fall shortly after it has been cut, the second growth or aftermath is almost always rusted, and so a second crop of uredospores is produced. 4. Since ‘‘ intermediate hosts,’’ such as the barberry, are not concerned in carrying over the rust from season to season, it has been suggested that infection may be communicated to the wheat from other grasses which, as we have elsewhere shown, may also be attacked by Puccimia graminis. Klebahn?! (p. 230) has shown that uredospores from various grasses will infect wheat, and it remains to be determined how far the grasses occurring in our wheat-fields, and attacked by this rust, are capable of infecting it. 5. Towards the end of the growing season, a second kind of spore is produced, known as the teleutospore. It will not germinate immediately, but only after a period of rest, and it may also aid in carrying over the rust from season to season. But although it can germinate in the spring, and produce other minute spores known as sporidiola, still they have not been proved to infect the wheat-plant, and so we do not know what pur- pose they serve, if any. In other countries they are said to germinate upon barberry leaves, and produce the aecidial form of the rust—and it may be that here they are simply dying out—are becoming functionless, because the barberry bush which they normally infect is not now available for them. 6. There is stil] another way in which some rusts are propagated, and that is by means of the threads of the fungus or mycelium remaining in- side the seed and starting into life with the germination of the grain. But although hundreds of seeds have been carefully examined by the micro- scope, no trace of this has been found, and therefore for the present we must decline to regard it as a probable cause. 7. There still remains another possible means of continuation from sea- son to season, which has been prominently brought forward by one who has devoted considerable attention to the study of the rusts in Sweden, Profes- sor Eriksson. Although he has not yet succeeded in giving scientific proof of his theory, he considers that while infection by spores does occur, yet the primary infection is from within, from an internal germ of disease inherited from the parent plant and latent in the seed. He grew wheat in closed chambers, where it was believed to be secure against infection from without, and still the rust appeared all the same, and he can only account for this by supposing that in the cells of the seed the protoplasm is asso- ciated with the plasma of the fungus—what he calls mycoplasm—and from this there arises, if the conditions are favourable, the mycelium of the rust fungus, quite independent of external infection. He does not seem to have considered the possibility of the spores of the fungus being attached to the seed, and until the soil and the seed are thoroughly sterilized and every precaution taken to exclude infection from without, and the disease still produced, until then we must suspend our judgment and accept the Scotch verdict of Not Proven. A very striking case, however, that the seed may be the means of continuing rusts from season to season is given by Carleton? in connexion with Euphorbia rust (Uromyces euphorbiae, Cooke and Peck). The pods of Euphorbia dentata, and even the naked seeds, were found to be affected with aecidia, and on growing the rusted seeds under a bell-jar, those that were disinfected produced plants without rust, while those not disinfected gave rise to rusted plants. Here the seeds actually bore the aecidia, and propagated the rust through the germinating seed. A similar instance is met with in Aecidium platylobii McAlp., where the aecidial cups are borne on the pods, and on opening the diseased ones, the seeds are frequently found covered with the mycelium, which, on microscopic examination, is found to penetrate them. ) Wheat Rust in Australia. 71 PREVENTION OR MITIGATION OF THE RUST. The all-important question now remains to be answered, how to pre- vent or mitigate the effects of the rust. In the various reports of the Rust-in-Wheat Intercolonial Conferences, special attention was paid to the solution of this question, and the effect on the crop of different cultural methods jreceived a large share of attention. Drainage.—It is commonly affirmed that rust is worst in hollows, where water lodges, and on general grounds it is considered that drainage by removing the surplus moisture would tend to afford the wheat the most favorable conditions for its healthy development, and thereby render the rust less injurious. But, as a matter of fact, when it was experimentally tested in Victoria, an increased yield was the result ; but as regards rust, it did not seem to affect it, for out of six areas artificially drained, five of them were rusty. In a number of our wheat-growing areas, it is not excess of moisture in the soil, but deficiency of it, which is complained of, and in such areas the rust is very severe in seasons marked by copious late spring rains. Irrigation.—At the present time irrigation is the great problem which overshadows all others in connexion with the utilization of the land in Aus- tralia, and its relation to the development of rust has not been overlooked. In irrigated areas where wheat was grown, the effect was observed, and it was seen that the judicious application of water was beneficial if done at the right time, and with due iegard to atmospheric conditions. There is only one rational method of irrigation for wheat in Victoria, and pro- bably for all Australia, and that is a thorough soaking of the ground prior to ploughing. Mr. Geo. Pagan, of Ardmona, who has successfully irrigated in the Goulburn Valley, states in the Journal of the Department of Agriculture for March, 1905, that his routine practice is to flood the land in March, unless there has been heavy rain, and then plough as soon as the horses can work without sinking. This one watering, followed by proper working of the land, will usually mature the grain. Even in 1902, when the year’s rainfall was only six inches, this was the case. The application of water later in the growing season is always risky, and often does more harm than good. It spoils the grain, making it soft, may bring on rust, and results in very uneven ripening. Seed-bed.—A relatively dry and firm seed-bed is generally considered best for wheat, and especially if there is a prospect of rain after sowing to ensure a good germination. Its effect on rust has not been definitely determined, but farmers are generally of opinion that sowing on a dry seed-bed gives the plant a better chance to escape the rust. If the seed- bed is moist, the condition will be favorable for the rust-spores on the soil, or on the grain, to infect the germinating wheat-plant, but probably it is not so much the nature of the seed-bed as the aftergrowth which will affect the result. This also applies to the mode of sowing, for it did not appear to make any difference, as regards rust, whether the wheat was sown broad-cast or drilled. Ploughing and Harrowing.—The question of deep as opposed to shallow ploughing does not seem to have much to do with the rust. In experi- mental tests, deep ploughing yielded the heavier crop, and thus indirectly favoured the development of rust; but both were about equally affected. Harrowing when the crop was about two feet high was equally incon- clusive. Rotation.—Rotation is undoubtedly good for the crop, and is a factor in clean cultivation ; but it is another question whether it is good or bad for a2 Wheat Rust in Australia. the rust. At Port Fairy, in Victoria, where rotation is regularly prac- tised, and where I have had crops grown the same season, sometimes after mangels, or potatoes, or onions, ‘there was no perceptible difference in rustiness from those crops of wheat grown in succession. From the stand-point of good farming, it is to be recommended ; but cropping year after year does not seem to affect the liability to rust further than this, that self-sown wheat is likely to appear in the interval between the two crops. Such ‘‘ volunteer’’ wheat, if not killed in cultivating, is much more forward than sown grain, and on account of its earliness may escape the rust, but on the other hand, there is a risk attending it, for it is some- times more rusty than the ordinary wheat, and appears earlier, so that it is one of the means of carrying over the rust from one season to another. All such wheat should therefore be kept down by means of sheep. Fallowing.—This practice is similar in its effects to rotation as regards rust. Professor Lowrie, speaking from a large experience in South Aus- tralia, considers that the apparent exemption which fallow-land sometimes enjoys from rust is due to the fact that it is customary to sow bare fallow- land first, and the crop ripens sufficiently early to escape the rust in some seasons. Burning Stubble-—It is sometimes recommended to burn the stubble in order to destroy any spores of rust that may be about; but as a matter of experience, this has not been found to produce any appreciable differ- ence. ‘Theoretically, the burning of the surface of the soil should destroy a number of spores, and to that extent is beneficial ; but, practically, the difference in result is not marked. As far as most wheat-soils are con- cerned here, the loss of vegetable matter is much more serious than any possible increase of rust. Soils—Soils are sometimes said to be rust-liable and rust-free, like the wheat itself; but on closer investigation, it will be found that the soil is only one of several factors that require to be taken into consideration. Rich soils are said to suffer most, and in rusty years the best crops have sometimes been raised from the poorest soils. On the rich soils the crop is naturally heavier and more luxuriant than on poor soils, and the softer and more susceptible tissues are easily invaded by the parasite. | Hence it is that the rust may sometimes be worst in the best crops. The mallee, in Victoria, is said to be particularly rust-free ; but in some seasons the crop has to be cut for hay, in order to save it from being completely destroyed by rust. The reason for general freedom from rust lies not so much in the soil as in the light rainfall and the early ripening of the crop. But if “muggy” weather should prevail when the wheat is flower- ing, then the crop is just as liable to rust here as elsewhere. At Port Fairy the low-lying black soils more readily produce a rusty crop than the sandy soils, and this may be partly due to the fact that the dark-coloured soils absorb more heat, and are more likely to preserve the spores in a fit state for germination, or because they grow a heavier crop, which often lodges and thus encourages the rust. Manures.—Perhaps no means for the prevention of rust have been more thoroughly and continuously tested than the application of different manures. In all the States, as well as in New Zealand, experiments have been conducted to this end, and the general opinion has been expressed by a late Director of Lincoln College, New Zealand :—‘‘ No manure has yet been discovered that is a preventative of rust in cereal crops.’’ The tests were carried out under varying conditions, and, as might be expected, the results of one year were often contradicted by those of the next; still, it was generally found that nitrogenous manures favoured the rust, while phosphatic ones had a tendency to diminish it. Nitrogenous manures Wheat Rust in Australia. a3 tend to increase the amount of flag, and retard ripening, by affording an excess of nitrogenous food, whereas phosphate of lime tends to induce early maturity, and thus enables the crop to escape the rust to a certain extent. Treatment of Seed.—This was thoroughly gone into, since it is so often stated that the disease is in the seed. No doubt appropriate treatment destroys the spores entangled in the “brush,” but inside the seed no mycelium has been traced. A great variety of ‘‘ steeps’’ have been used, and I have myself experimented with over twenty, including the hot-water treatment ; but they were all of no practical benefit. Last season (1904) two plots of Queen’s Jubilee wheat were sown the same day and grown alongside of each other, in one of which the seed was treated with formalin, while the other was untreated. The rust was bad on both plots, and although special attention was given to the matter in the field, I could not say that treatment of the seed with formalin gave any advantage as regards rust. Both sulphate of copper and formalin destroy the rust spores on the seed-grains, and Dr. Hollrung, as the result of a series of experi- ments, has recommended the latter as the best for this purpose. But since infection chiefly takes place when the wheat plant is above ground, it is evident that the formalin treatment does not prevent it, and the experience of numerous farmers who have used formalin successfully for the treat- ment of stinking smut (Z7lletia tritic?), bears this out. The hot-water treatment of the seed is constantly being brought forward as a remedy for rust, but in 1892 the seed for 118 plots, consisting of different varieties of wheat, was treated with hot water at 55 deg. C., and in some cases the rust was just as bad as if no treatment had been given. It was adopted as a conclusion at the last Rust-in-Wheat Conference that the treatment of the seed is valueless for rust, and Dr. Cobb? one of the representatives of New South Wales, went so far as to say :— ‘“ As for curing rust by treating the seed, the idea is ridiculous. It would be just as reasonable to expect to prevent measles among mankind by soaking babies in some sort of pickle.’’ It has not been thought necessary to refer specially to spraying as a means of combating the rust ; for although this method is practicable in an orchard, and has been found successful in treating peach and plum rust, still the mechanical difficulties to be overcome in spraying a wheat-field are so great, that it is no longer regarded as of practical importance. So far it would seem as if the rust in wheat defied treatment, and the only practical measures to be recommended for mitigating its effects were to sow early and to select early maturing varicties. In this way it is often possible to escape the rust, or the crop is too far advanced to suffer seriously. But in this, one is at the mercy of the weather, and the only hopeful remedy is to grow wheats which will be able successfully to resist the rust, even when the weather favours its development. The question has been raised as to whether a wheat which resists one kind of rust can succumb to another in a different country, and this has really been found to be the case. Professor Eriksson sent me ten varieties of Swedish wheats which had been grown in the experimental plots, and found to resist the rust which is prevalent in that part of the world, viz., Golden Rust (Puccinia glumarum). When grown here these rust-resisting Swedish wheats became rotten with rust, although of a different kind; and this, along with other experiments, points to the possibility that a wheat may resist a rust such as P. graminis in one country and succumb to it in another. Selection and Cross-breeding. — As the result of numerous experi- ments, and the trial of hundreds of varieties of wheat from all parts 74 Wheat Rust in Australia. of the world (Europe, Asia, Africa, and America), it has been proved that no wheat is absolutely rust-proof, that is to say, there is no wheat known which will be proof against the rust when grown under conditions favorable to its development. But the same experiments have shown that among a number of varieties grown in a particular district, some will resist the rust more than others, are able by their constitution—it may be by their vigour of growth or toughness of their cuticle or glaucousness, or all combined—to resist the inroads of the rust sufficiently to prevent its seriously injuring the grain, and such wheats are known as rust-resisting wheats. At present we have at least one such wheat which has been grown in various districts of different States along- side of other wheats badly rusted, and it has been able to withstand the rust. Rerraf is the wheat referred to, and perhaps it, too, in course of time, will succumb to the rust. For this great and burning rust-question the only measures I can suggest are :— 1. To produce wheats suited to our Australian conditions by crossing, as Mr. Farrer, Wheat Experimentalist of New South Wales, is now so successfully doing. 2. To select and carefully cultivate the most rust-resisting plants from these and other wheats having the necessary hardy, prolific, grain-holding, and milling qualities, keeping up the strain and constantly renewing their constitutional vigour. 3. To cultivate early maturing varieties and sow them early, combined with the best agricultural methods, such as clean cultivation, judicious rotation, suitable (phosphatic) manuring and fallowing, to insure a good crop. In judicious crossing and careful selecting lies the solution of the great rust problem, as far as our present knowledge goes, and to increase and extend this knowledge it would be desirable to follow the advice of Professor Eriksson, who has done more than any other single individual to enlighten us on the subject :—‘‘ The question of the rust of cereals being of the greatest practical importance for every country, means should be furnished to those in whose hands the direction of these investigations are placed, to meet from time to time, that is to say, at least every five years, in order to discuss, according as experience is gained, the value of any new observations, and to gain for their work the advantage of being based on a plan common in its essentials to all.’’ Rust in wheat has been known in Australia for at least 80 years. H. C. L. Anderson, Principal Librarian of the Public Library of New South Wales, informs me that the earliest record of it is given by Atkinson,! who, referring to 1825, or even earlier, says that “ rust sometimes appears, but it is not very common.” J. Montague Smith, in 1828, notes that the plains and forest lands of the Hunter district of New South Wales suffered from rust in wheat. As the wheat-growing area extended, the rust also spread with amazing rapidity, until now it is undoubtedly the most widely distributed and the most destructive of all the diseases to which cereals are subject. NOTE I. P. 4.—Eriksson}§, in his latest work on the vegetative life of Puccinia graminis, has described and figured a transition from the mycoplasm to the protomycelial stage, but it still remains to be seen how far his interpretation of the facts is borne out by other observers. Wheat Rust in Australia. a5 NOTE 2. P. 14. —Christman!, however, has clearly shown that two fertile cells or swollen hyphal branches come into contact, and at the point of contact an opening is formed by solution of the cell wall, and thus their contents mix although the nuclei do not fuse. There is thus true sexual cell fusion with- out the intervention of spermatia. NoTE 3. P. 24.—Arthur$ considers the sorus in such species as Puccinia bromina and P. ¢riticina to be compound and the modified hyphae which separate the individual sori to form a stroma, hence they are not paraphyses, strictly speaking. NOTE 4. P. 37.—The origin of the aecidiospores as shown by Christman,! from the fusion of sexual cells and the peridium from morphologically equivalent cells disposes of the view that the aecidiospores may have been derived from teleutospores. If, as Blackman suggests, the rusts originated from the red algae, then the sexual product or aecidium would represent an early stage in the history of the Rusts. NOTE 5. P. 43.—Hooker, in his classical essay On the Flora of Australia (1850), has a chapter on some of the naturalized plants, showing that even nearly half a century ago, the chick-weed, knot-weed, scarlet pimpernel, daisy, mallow, sweetbrier, and various other common plants had been introduced. The groundsel, however, is not mentioned, and no doubt as trade increased with other countries and exchange of products took place, the importation of the seeds of weeds became common. Note 6. ‘ P. 62.—Beauverie! has experimented with Botrytis cinerea, or grey rot, and obtained, in sterilised soil, an attenuated form of fungus. He infected soil liberally with this form, and grew plants therein from seeds and cuttings perfectly free from the fungus, while plants not rendered immune in this way perished. NOTE 7. P. 68.—Kirk informs me by letter what he has already stated in his Annual Reports that ‘‘ Barberries are being largely used in New Zealand for hedges, and, up to the present, I have never seen any sign of aecidia of Puccinia graminis on them, although I have examined hundreds. It would appear as if Puccinia graminis in Australia has lost the power ot forming aecidia on barberries.’’ Note 8. P. 69.—Bolley,> however, has announced that he found the uredospores of Puccinia graminis successfully surviving upon dead leaves and straw, even retaining their vitality when exposed to the drying winds of autumn, and the intense cold of winter. of , ® ara ‘ “ae naires , Lah Ts iat ak att a wat n i . ai hr iy Mie 4 ite 708. alte: rea et MAP 13 Re Ata = Wa ' ae eee fi Bets a. Eves eee Ss Sis Y ‘85 — : ; -E Aes bot, ~ aa? 7, tks WA Se gaan NK eh ron! tha ME SER avharebiany, tee Git sadtad belive wht ae Peueauon | ; arties Ce aun tsi) Wieig 260. yok TUR eon lise & used oi , : : u » oh 7 agar c AY need tart? y b aha rete sah Av Rep hon mgt aii r- yo aee f Ale i) Sa any, ce ibis aay { wk sive laaes ; 7 nen 'g' el ova 728 pyvinpeodraa Miz ape, nln git Ba ip ot lathe cee od iiayre tamale ae en fats baa th isles iat Piney cnlires ia uber fess owl augh oct 1g. eruldety Laney) eres ee Li dogo inal the ( M ay ee ca e ‘re ‘ i yeh + & cera) o@ “ y “te | u Po i a inn A} “\ AK oe Ray i ep ti Es ce . % .s Site 4 tA. } ag? lye i. ME Nie rey G. H. Robinson, Phot. , < 250. PUCCINIA. COMPOSITAE. ‘> 256 Explanation of Plates. PLATE VIIL. (Ali Figures X 250.) PUCCINIA. Fig. ait of teleutosorus of Puccinia cinerariae on Cineraria sp. cult. with teleuto- spores and mesospores. 61. Three uredospores and several teleutospores of P. cichorii on Cichorium inty 62. Uredospores and teleutospores of P. hypochoeridis on Bippathioe radicata. 63. Teleutospores of the same. 64. Two uredospores and numerous teleutospores of P. cyani on Centaurea cyanus. 65. One mesospore and several teleutospores of P. calendulae on Calendula offi 66. Mesospores and teleutospores of P. brachycomes on Brachycome ciliaris. 67. Teleutospores and mesospores of P. distincta on Bellis perennis. Puare VIII G. H. Robinson, Phot. i « 250 PUCCINIA. COMPOSITAE. 7 e ae 258 Explanation of Plates. Fig. ou 68. 69. 70. 71. 72. 75: 76. PLATE IX. (All Figures X 250 unless otherwise stated.) PUCCINIA. Three uredospores and four teleutospores of Puccinia thuemeni on Apium pros- tratum, showing thickened apex of uredospore and slight warting of teleuto- spore. Beaumaris, Victoria. Uredospores and teleutospores from same, but in greater variety. One uredospore and two teleutospores from the same, but more highly magnified, and showing more seen the eee ce a of both uredo and teleuto- spores ... : ace sa 32 OS Teleutospores of P. thuemeni on Apium graveolens, from Brighton, Victoria. Uredospore and teleutospore from the same as 71, showing roughened epispore in both forms more clearly Arie aoe Sob Ser eee X 500 . Uredospores and teleutospores of P. aii on Apium graveolens, Berlin, Ger- many. (Sydow, Uredineen, 558.) . Teleutospores as in Fig. 73, showing distinctly smooth epispore .- 2) 568 Teleutospores of P. Gullata on Aethusa es as with coarsely warted epispore. (Sydow, Uredineen, 1261.) .... : “tf =e X 500 Teleutospores of P. xanthosiae on Xanthosia pusilla. PLATE IX. PUCCINIA. UMBELLIFERAE. 260 Explanation of Plates. PLATE. &. (All Figures X 250.) PUCCINIA. Fig. 77: 78. 79: 8o. Si. Teleutospore of Puccinia oliganthae on Asperula oligantha. Teleutospores, some having germinated, of P. coprosmae, en Coprosma hirtella. Uredospores and teleutospores of P. epilobii-tetragoni on Epilobium glabellum, Murramurrangbong Ranges, Victoria. Uredospores and teleutospores of P. epilobii-tetragoni on Epilobium montanum. (Sydow, Uredineen, 1369.) Teleutospores of P. epilobii DC. on Epilobium roseum, the teleutospores having much thinner walls, and being more variable in shape than those of P. epilobii-tetragoni and also finely verrucose. (Sydow, Uredineen, 1418.) . Teleutospores of P. get on Geum renifolium. . Uredospores of P. prunt on Prunus persica. . Paraphysis and uredospores of P. pruni on Prunus persica. . Teleutospores of P. pruni on Prunus persica, rather smaller than average. . Teleutospores of P. pruni on Prunus domestica. . Uredospores and teleutospores of P. zorniae on Zornia di phylia. RiArEixe PUCCINIA. RUBIACEAE, ONAGRACEAE, ROSACEAE, anno LEGUMINOSAE. “ye e - na : . oay on i 5 rai yo 2) ee eee 7 by ate ewe wie ‘ye ia te te Semen ,) MRT ae. ee ha b ) ov Gt ; Poy i 7 .) today te ) silica) ak Wad) ‘ > | >| se Mee ee Tear 7 j ye > ot bi Bela 8 ; P ae ipa: al | By hus ’ ay r hy fh anyagh "yn ree tial, Oe j . it in wy 3 ° > 7 rit e-Pud 7. i x ‘ ee htthe Pd a lah anu: a” inal cry Ba ks | f Me, =" yi) r y> 7 i} y ‘ mie “iD VF 2 ae ; ' a 5 Mie) . i i wae, 4 < : : 4 a j i Ais Wie id ma! Ri atamngilag ena Pi har Mes fie | 262 Explanation of Plates. PLATE XI. (All Figures X 250.) PUCCINIA. Fig. . 88, 89. Teleutospores of Puccinia tetragoniae on Tetragonia implexicoma, one with 90. gl. 92. 93- 94- “D5 96. nearly vertical septum in upper cell. Teleutospores, strongly warted, of P. ludwigti on Rumex flexuosus. Teleutospores strongly warted, of P. Judwigii on Rumex brownii, one spore being Triphragmium-like. Uredospore and teleutospores of P. acetosae on Rumex arifolius, all the latter with smooth walls. (Sydow, Uredineen, 954.) Teleutospores of P. muchlenbeckiae on Muehlenbeckia adpressa. Teleutospores and mesospore of P. dielsiana on Threlkeldia sp. Uredospores of P. kochiae on Kochia sedifolia, showing the characteristic nume- rous germ pores. Teleutospores of P. kochiae on Kochia sedifolia. PLATE XI. G. U1. Robinson, Phot, x 250. PUCCINIA. FICOIDEAE, POLYGONACEAE, ano CHENOPODIACEAE. ‘+ 7" os * 4q 7 . 4 tN 2° ee . . ij 4 ned i i 7 A aay © 4 ‘ je - jut ww ’ ? ‘aj ‘ Pict kee | Th ihe ee « pre iy H > ¥ ee? i + 4 Ay 4 » “OW i , \ : F 7 % #2 “t o.” i 264 Explanation of Plates. — ; PLATE XII. (All Figures X 250.) PUCCINIA. Fig. 97. Teleutospores of Puccinia arenariae on Stellaria media. 98. Teleutospores of P. plagianthi on Plagianthus sidoides, the epispore being slightly channelled. 99. Teleutospores (stained) of ?. malvacearum on Malva rotundifolia. 100. Teleutospores and mesospore of ?. malvacearum on Lavatera plebeia. ro1. Teleutospores, mostly one-celled, of P. “eterospora on Abutilon crispum. 102. Teleutospores and mesospores of P. morrisoni on Pelargonium australe. 103. Uredospores of P. geranii-pilosi on Geranium pilosum. py a 104. Teleutospores of the same, the single germ pore being noticeable as a paler channel through the apex of the cell wall. Prats XI. G. H. Robinson, Phot. PUCCINIA. CARYOPHYLLACEAE, MALVACEAE, «no GERANIACEAE. +> 266 109. 110. Ill. II2. Explanation of Plates. PLATE XIII. (All Figures x 250 unless otherwise stated.) 6 PUCCINIA. . Teleutospores of Puccinia ertostemonis on Eriostemon myoporoides. * . Teleutospores of P. correae on Correa lawrenciana. 7. Teleutospores and mesospores of P. borontae ou Loronia spinescens. . Teleutospores and mesospores of P. fritzeliana on Tremandra stelligera, some teleutospores having germinated. Teleutospores of P. hederaceae on Viola hederacea. Teleutospores of the same, more highly magnified, to show more clearly the slightly warted epispore sec rie “a aoe PSB x 500 Teleutospore of P. aegra on Viola tricolor with smooth epispore. (W. B. Grove in Rabh. Fungi Europaei, 3113) Sis 55: nae oe X 500 Teleutospores of P. violae on Viola arenaria, wtih smooth epispore. (Sydow, Uredineen, 286) Sa? 45 ee a ins ae xX 590 G. H. Robinson, Phot PUCCINIA. RUTACEAE, TREMANDREAE, AND VIOLACEAE PLatTe XIII. x 250 and 5U0. oe i ‘ ; Pa * im Vv a 268 Fig. > TEs 114. 11S, 117. 118. 110. 120. 121. 122. Explanation of Plates. PLATE XIV. (All Figures * 250.) PUCCINIA GRAMINIS on VARIOUS GRASSES. Teleutospores and mesospores on wild oat, Avena fatua. Teleutospores on barley, Hordeum vulgare. 116. Teleutospores, mesospores, and uredospore, one of the first three-celled, on native barley, Echinopogon ovatus. Teleutospores on cocksfoot, Dactylis glomerata. Teleutospores and uredospores on silver grass, Festuca bromoides. Teleutospores and uredospores on an imported barley grass, Hordeum secalinum. Teleutospores on small canary-seed grass, Phalaris minor. Teleutospores on native wheat grass, Agropyron scabrum. Teleutospores on Amphibromus neesii. G H. Robinson, Phot. PUCCINIA GRAMINIS ON VARIOUS GRASSES. 270 Explanation of Plates. PLATE XY. (All Figures X 250 unless otherwise stated.) . GERMINATION or TELEUTOSPORES or PUCCINIA MALVACEARUM. Fig. 123. Germinating teleutospore, from each cell of which a promycelium has been pushed forth, cell contents collected towards apex of tube, and segmentation commenced. 124. Germinating teleutospore at a later stage, the promycelium having become divided into four segments, and comparatively stout tubes emitted from each seg- ment. 125. Two germinating teleutospores, in the one on the left only the two median seg- ments of the promycelium as yet bear sporidiola. 126. Germinating teleutospore with stout elongated and contorted filaments arising from the promycelial cells, those from the two median cells ultimately giving rise to abnormally small sporidiola. 127. Germinating teleutospore in which the upper two promycelial cells have produced sporidiola, while in the third from the apex the formation of the sporidiolum is just commencing. 128. Germinating teleutospore, the promycelium bearing three sporidiola on stout elongated sterigmata. The sporidiolum second from the base is already germinating and putting forth a germ tube extending across to the promy- celium. The segment second from the apex has not so far produced a sporidiolum, though a stout elongated filament has been emitted. 129. Promycelial spores a bs abe ste So Sy X 500 130. Germinating promycelial spore... =e sry Ane “ie X 500 Norre.—All the above were grown in droplets of water on slides in a moist cham- ber, and prepared for photographing by being first dried, then fixed with a saturated solution of mercuric bichloride, washed, rinsed in dilute acetic acid, washed again, and after drying stained with alcoholic Bismarck brown, again washed and mounted in glycerine and water. : PUCCINIA. TELEUTOSPORE GERMINATION OF P. MALVACEARUM. a a woe i eo ao ‘ Fel Aya no we. ae § . A I P Peay ; oe st i ‘i ite ne - ie y As sik rs Mi ae Fig e Mee aah 272 Explanation of Plates. PLATE, XVI. (All Figures X 250.) UROMYCES. 131. Group of teleutospores of U/romyces danthoniae on Danthonia semiannularis. 132. Teleutospores of U. ehrhartae on Microlaena (Ehrharta) stipoides. 133. Teleutospores of U. tenuicutis on Sporobolus indicus. 134. Two one-celled and one two-celled teleutospore of U. tricorynes on Tricoryne elatior. 135. Teleutospores of U. tricorynes on Tricoryne elatior. 136. Uredospores of U. thelymitrae on Thelymitra antennifera. 137. Teleutospores of the same. 138. Teleutospores of U. orchidearum on Chiloglottis diphylla, from original type material in National Herbarium. 139. Teleutospores of U. microtidis on Microtis porrifolia from type material from Massee. Pouate XVI G. H. Robinson, Phot. x 250 | UROMYCES GRAMINEAE, LILIACEAE AND ORCHIDACEAE. ’ may 7. Mt r 1 j ‘PF AL a TIS aah ‘ i, } 2 {ree > 1 i 4 ® » a? 4 Ast 5 < ser Vt ie aA i¢ » = a. [ ' F ry i = ie 4 “9 “Hy ir¢ ; aha ah Bian Se i. " a ae : . P s - t “ia ag hh ‘i! ; a ay t 7 tlhe sor! Sas ‘. he a) - | 7 wet ‘ A 0 im ne i Oa: = >) 7 ‘ nL 7 b) ‘ ‘ ‘ i f A iu ’ — jie wid 5 r ih Vea m i ; ‘ fi eh! k PI / ' p a 4 ’ j ait nis d 4 i bs - ‘ t .! E a P - , ‘ : SRN pi ds A masil ait ade |i i i ay « vit i é ~ | 7 RP) i 274 Fig. 140. 141. 142. 143- 144. 145. 146. 147. 148. 140. Explanation of Plates, PLATE XVII. (All Figures X 250.) UROMYCES. Group of teleutospores of Uromyces puccinioides on Selliera radicans. Teleutospores of U. asperulae on Asperula oligantha. Uredospores and teleutospores of U. ¢rifolii on Tip alae repens. Uredospores of U. hardenbergiae on Hardenbergia monophylla. Teleutospore of the same. Two uredospores of same at top and one teleutospore below. Section of teleutosorus of U. atriplicis on Atriplex semibaccata The teleuto- spores are faintly striate with one prominent germ pore at apex. Two teleutospores of same at left and four uredospores at right. Uredospores of U. betae on Beta vulgaris. Teleutospores of same with prominent hyaline apiculus. Puate XVII G. il. Robinson, Phot X 50. UROMYCES. GOODENIACEAE, RUBIACEAE, LEGUMINOSAE, AND CHENOPODIACEAE 276 Fig. 150. 15r, 152. 153- 154. P55. 156. 157. Explanation of Plates, PLATE XVIII. (All Figures X 250 unless otherwise stated.) UROMYCES. Uredospores of Uromyces polygoni on Polygonum aviculare. Teleutospores of same. Uredospores of U. caryophyllinus on Dianthus caryophylius, with prominent scattered germ pores. Teleutospores and one uredospore of same. Section through leaf of Dianthus caryephylius, showing uredosorus of U. caryo- phyllinus with two pycnidia of Darluca filum growing upon it, and two young pycnidia on opposite surface of leaf... 0 a x 50 Uredospores of U. vesiculosus on Zygophyllum glaucescens. Teleutospores of same. Two-celled teleutospore of same. PLATE XVIII G. H. Robinson, Phot X 50 & 230. UROMYCES. POLYGONACEAE, CARYOPHYLLACEAE, AND ZYGOPHYLLACEAE. Le, ee ™ - me: 6 J * ‘ey i £ : \ a 4 Hi mea ee i vate Oe Se eB ED ; : ao. Ss « bt a REY ae me th sah ? ar a i So els ee i, weal Nie Ue ; 41 a, ams Bite eon! ue win | ; ; s - Raed by airs a) enreae La y Gi: >) Nay a " ting An i ; Seer AAS ‘ a | ee oe oe pe Cente? : ee : . | ; \?7 oie Ve ia le my. Ti) res) pt Auee yo : . y us mieund ia 9 oe ; y vedi j 4 | t - 3 , | : ‘ nee. ; se "eqs teerad Wee : ik pitt jen mir . i . 4 . i oe ; a | 278 Explanation of Plates, PLATE XIX. (All Figures X 250 unless otherwise stated.) UROMYCES. Fig. 158. Teleutospores, seen from above, of Uromyces fusisporus on Acacia neriifolia. 159. Side view of same. 160. Uredospores of same, with pronounced apiculus and equatorial band of germ pores. UROMYCLADIUM. 161. Teleutospores of Uromycladium simplex on Acacia pycnantha, part of the pedicel being still attached with the remains of the vesicle. (Stained). 162. Young teleutospores of the same showing the vesicles still attached. (Stained). 163. Portion of flake of gummy material on leaf of Acacia pycnantha, in which nume- rous teleutospores of U. simplex are embedded, nearly all germinating and producing sporidiola. 164. Germinating sporidiolum of same. (Stained) vee one oh x 500 165. Uredospores of same, being very similar to those of Uromyces fusisporus, fig. 160, though somewhat shorter and broader and possessing more germ pores. G. H. Robinson, Phot. UROMYCES AND UROMYCLADIUM. LEGUMINOSAE-—ACACIA. ta te Ay Ash ON bn MY o hu ae — ma iin a 280 Explanation of Plates. PLATE XX. (All Figures X 250.) UROMYCLADIUM MARiTIMUM. Vig. 166. Section of teleutosorus of U. maritimum on Acacia longifolia, the mature teleutospores having the remains of the vesicles attached to the pedicels. 167. Group of mature teleutospores of the same. 168. Formation of teleutospore head ; a young cluster, showing the two young spores at the apex, and the lateral vesicle below the septum. (Stained.) 169, 170. Similar heads, more advanced. (Stained.) 171. Mature teleutospore head, two teleutospores above and one vesicle below. 172. Abnormal development of head of teleutospores, the lateral vesicle being re- placed by a true spore, and a septum placed in the stalk beneath it. In the normal head of two spores and a vesicle there is no septum below the vesicle. 173. Teleutospores germinating while still attached to each other; two sporidiola on one promycelium, others so far undeveloped. 174. Uredospores with prominent equatorial germ pores and serrated epispore, thickened and dentate at apex. 775. One-celled spores (mesospores ?), occasionally found intermixed with uredo- spores. 176. Immature two-celled colourless spore, of same character, from uredosorus. (Stained). ; PiGArH exeX UROMYCLADIUM MARITIMUM. LEGUMINOSAE—ACACIA LONGIFOLIA. a A iad per COTS | eS eee ie wa. Ate) HOLL: biel ts ; liiylos Wii OWT mpery NS wiaest iis bay's) 7 f i ia) dn . F j Be: ye wee fayeie nt Si. aa ley ' r TR auct 7 qin din ld iy \ ‘aes iis i 4 “ial 4, i i>! : ‘ican . j j rn +) Wipes i vee) i, i615 iA ee pwn a Ff hk een basa Beri dia li te d ty hit) a . fi i4 eg sey ci 0 ub : coang ; 4 ee he 4 : mi)" a ae ; »H aye A923) 4 ' sreté + 4 Mies “ed vt iw) m9 aie Wi) Ca wie a ibs me d yiihind bass View! wat jiu ey. ‘ rf . a lh 4 att mma F at “40% ah? ferdta} } Lat wie ne “ : . PN ae) AN Re his fi ie 4, Z ‘ My , ae ~ ee | | ; y ri ; : nt if, ° ff as ¥ H 4 ‘- | ‘ if 4 A 4 d a) , fe q AY | F ar tin) Ai i. se ae va A PT ee ee hd ed eT Oe ek | - 282 Explanation of Plates. PLATE XXI. (Adi Figures X 500.) UROMYCLADIUM MARITIMUM. Fig. 177- Two young teleutospore heads, arising from common stalk, the one on the right being younger than that on the left, and both intermediate between T2 and T3 in next figure. (Stained.) 178. Main stem, bearing teleutospore heads in various stages of development; T, filament with two septa, the upper two segments destined to become teleuto- spores, the lowermost a vesicle; T1, similar filament, somewhat more ad- vanced, the vesicle beginning to push out from the lowermost segment; T?, similar filament still more advanced, the uppermost cell distending, in the next growth is taking place at the side, and in the lowest the vesicle has attained considerable development; T3, nearly mature head, with two dark teleutospores; U, basidium of a detached uredospore. (Stained.) 17g. Abnormal teleutospore head of three teleutospores, a septum beneath the lower- most. :80. Normal teleutospore head, with two teleutospores above septum and a vesicle below, there being no septum below the vesicle. 1&1. Teleutospore head in which the vesicle is apparently at the apex, but this is probably due to displacement in mounting. 182, 183. Normal teleutospore heads. 184. Uredospores with prominent germ pores, serrated epispore thickened and dentate at apex. ie i i i PhatE XXII. UROMYCLADIUM MARITIMUM. LEGUMINOSAE—ACACIA LONGIFOLIA. s% i] 190, 7193- 104. Explanation of Plates. PLATE XE. ! {All Figures X 250 unless otherwise stated.) UROMYCLADIUM. 186. Uredospores of U. robinsoni on Acacia melanoxylon. The solitary large smooth-walled spore (?) in Fig. 186 is difficult of interpretation. 7- Young and mature teleutospores of same, with and without attached vesicles. (Stained.) . Mature teleutospores of same, with vesicles. Mature teleutospore of same germinating, the sporidiola just about to be formed. (Stained.) 191, 192. Successive stages in the development of a teleutospore head of U. tepperianum on Acacia salicina, the striated epispore being clearly shown in 192. (Stained.) se oes oF wee ee Pe X 500 Single teleutospore of same, seen from above, and showing striated mark- INGS ... cae 4g: sie ae es “i oo xX 500 Mature teleutospore head of same. (The markings are indistinct on account of poor condition of material) oe oer a ee X 500 5. Detached teleutospores of same. GATE Ne Noll G. H Robinson, Pict. : x 250 & 600. UROMYCLADIUM. LEGUMINOSAE-ACACIA. Fig. L Tyo. 200. 261, 203. 204. 205. 206. Explanation of Plates. PLATE XXIII. (All Figures X 250 unless otherwise stated.) UROMYCLADIUM. Uredospores of U. notabile on Acacia notabilis. Original type material of Uredo notabilis Ludw. (Somewhat swollen by lengthened treatment with caustic potash.) . Uredospores of the same, showing the net-like surface markings. .... X 500 . Compound stem, with basidia and uredospores of the same. - Compound structure from uredosorus of same, being probably commencement of teleutospore formation oes ae aes az as X 500 Uredospores of U. notabile on Acacia dealbata. 202. Uredospores of the same, showing the net-like surface markings... X 500 Portion of spermogonium of the same, with basidia bearing spermatia in chains. (Stained) ae As a ses a X 500 Cluster of three immature spores of the same, attached to their stalk. (Stained.) Mass of mature teleutospores of the same, separated from each other, from Acacia decurrens. Mass of scarcely mature teleutospores, separated from each other, of U. ¢#ep- perianum, on Acacia melanoxylon, from Cheltenham, showing striated mark- ings on the surface. These are considerably smaller than the average. PLATE XXIIT- G. H. Robinson, Phot. . x 259 & 500. UROMYCLADIUM. LEGUMINOSAE-—ACACIA. ‘ { ny! @ a IS 2 OM, We A: n° oe aa | yi eps ; Pr) A, tae ey Y ¢ f es TET ECU TOP (hj | re tS a Le | VA 288 Fig. 207. 208. 223; 235. 216. 217. Explanation of Plates, PLATE XXIV. (All Figures X 250 unless otherwise stated.) UROMYCLADIUM. Teleutospores of U/. bisporum, on Acacia dealbata, one cluster of two showing the common staik. Teleutospores of the same. . Uredospores of U. alpinum, on Acacia dealbata. 211. Teleutospores of the same. . Five uredospores of U/. alpinum on Acacia dallachiana, mixed with teleutospores and one mesospore (4). 214. Successive stages in the development of teleutospore clusters of the same. (Stained.} Group of teleutospores of the same. Section of leaf of Acacia longifolia attacked by U/. maritimum, the uredosori being at the margin of the inflated tubercle, and the spermogonia in the. centre ae us as es oe ae Ja 2 Deae Uredospore of U. maritimum attacked by some Hyphomycete, which has gained access to the interior of the spore and grown within it preparatory to forming the long septate threads which have pierced the wall near the germ pores. G H. Robinson, Phot UROMYCLADIUM. LEGUMINOSAE—ACACIA. PLATE XXIV. x 80 & 250. ie vy PPR ONS WS ney 7 eS, a © I Ay Skape atin gd) Tey Rw Ly Mae mPa ee: ee 4 . 3a j i F i s iis t alice. 52 a v4 Mu } ie. Ma y ea ) : ad wh e au Y, om ’ A J at = = t ‘ ; ah . i y ) i ! } ' ne jl “ite ny, , “9 (3) ad a . wd ; ‘ ‘ si ri 1 We ‘i ~ " Me Mi eM il ~ ~! ' ¢ ? ee ' i 5 290 Explanation of Plates, PLATE XXV. (All Figures X 250 unless otherwise stated.) UROMYCES PHYLLODIORUM. Fig. 218. Two uredospores of U. phyllodiorum (B. aud Br.) McAlp., on Acacia sp. from Queensland. (Type material of Melampsora phylicdiorum 8. and Br., from Herbarium of F. M. Bailey, Government Botanist, Queensland.) 21g. One of the very sparse digitate teleutospores present in the same material. 220. Uredospore from the same material ae a oe ws «=. X* 5OO (All the above from old and much faded material.) 221, 222. Uredospores of U. phyllodiorum, on Acacia sp. from Queensland. (Type material of Uromyces phyllodiae Ccoke wy Wilbta os * ee t ' aa Ea Cael Sel TY ¢ y : aT PE MMe Sra e . en 2 AVIA ZAR PLN Sos a i + 4 iV An: ei 'e4) % 7 J * = Like hie 1S SURG rs L * a I ee bi ‘ , 4 i % ‘ a ia? i i a Te ~ Po 9 ] 4 7. : a . ri? a na bhi} Fore ua IT" “he ree 318 Explanation of Plates. PLATE XXXIX. (All aecidia X 50, and aecidiospores X 300.) AECIDIUM. A. veronicae on Veronica sp. A. plantaginis-variae on Plantago varia. . lobeliae Thuem., on Lobelia pratioides, described in connexion with Puccinia aucta. The free margin ruptures irregularly, and it is sometimes difficult to detect a peridial wall, so that it partakes of the nature of a Caeoma. . cymbonoti on Cymbonotus lawsonianus. . monocystis on Abrotanella forsterioides. . vittadiniae on Vittadinia australis. A A A SA A A A solentiforme cn Goodia lotifolia. . deeringiae on Deeringia celosioides. . calthae on Caltha introloba. . ranunculacearum on Ranunculus rivularis. . Aecidium of Uromyces politus on leaves of Muehlenbeckia cunninghami—a. nat. size, 4. aecidia] tubes X 5. . Aecidiospores of same (X 300) and pseudoperidial cells (X 150). PLATE XXXIX i f | ‘ ' : : C. GC. Brittlebank, Del. x 5, 50, 150 & 300. AECiDIUM. fi DRGs cc. Aa teed inf | hid ‘pits ATA, Pe ay ed yt AW F SAN OMOMOITARIVI9IDS , re 4 ‘ 7 ve . z ; Ben \acraia Sie RMT Got wl - ‘a tea) eu wins) sls diws Bit 4 j 2 treat, Jil) b:: S07) 30) be af »j TES ee rene ai pig] AA ; Wer gt IO) lie, yiisieab jo ; lig Od pian 44) at) y piety 320 Explanation of Plates. PLATE XL. (All Figures X 500.) NORMAL sanpD ABNORMAL SPORES or PUCCINIA anp UROMYCES. - PUCCINIA DICHONDRAE. ig. 2ag. The teleutospores exhibit a great variety of shape and size, and range from one to four celled forms. In the two-celled forms the septum may either be transverse or longitudinal, and in the three-celled forms the septa may either be transverse or oblique, and the upper or lower cell may be divided longitudinally. The four-celled forms may, in addition, become somewhat spherical, and be divided longitudinally and obliquely, so as to resemble a Sphaerophragmium. The variation even in the same sorus is sometimes greater than it is between some different species. PUCCINIA LUDWIGII. 300. Teleutospores may be divided generally as in the above, although the four- celled forms are not quite so frequent. PUCCINIA GRAMINIS. 301. Teleutospores are also one to four celled, but the septa are generally transverse, while the upper cell may occasionally be longitudinally divided. PUCCINIA TRITICINA. 302. The teleutospores donot show sucha wide variation as in P. graminis, but they may be from one to three celled, and the upper cell may be longitudinally divided. UROMYCES ORCHIDEARUM. 303. This species shows very well the transition from the unicellular (Uromyces) to the bicellular (Puccinia) teleutospores. Some of the two-celled spores are equally divided by the transverse septum and constricted, se that they depart entirely from the Uromyces type. ] . ao I 328 Explanation of Plates. a 7 PLATE XLIV. i RUST-RESISTING anp RUST-LIABLE WHEATS. Fig. 320. Rerraf, a variety of wheat generally found to be rust-resisting, and the er is shown to be perfectly clean. 1. Queen’s Jubilee, a rust-liable variety, grown pene of the other, and badly , Bi ee by Puccinia graminis. Printer. Govt. d, ennrnn EOD: - 5; ln rin cntcind innate 39 prewmenne te ER, ANNO SET = RN Rees ---— enc NS o's eancincenmcareie nN ms ee a9 CMa TIN ORI Straw badly ruste CUO Cia Re SESS SS mae, ui Lu zal aa) ~ =) > ae FL Lu Lu zs) ‘OY Pn See RRR SB ete oa Br aNCENIRN ks hi aca om . sisaleitle ” SSOP ORRORHRR A pana TA opaaalaebap ina i MeN Straw perfectly clean, ELSA LL ODI MI LOO NEO -colour process, 2 7) re * t/ Host Index. 329 HOST INDEX. Abrotanella forsterioides Hook. f. Aecidium monocystis, Berk. Abutilon avicennae Gaertn. Puccinia heterospora, Berk. and Curt. Abutilon crispum Sweet. Puccinia heterospora, Berk. and Curt. Acacia L. Uromyces fusisporus, Cke. and Mass. Uromyces phyllodiorum (B. and Br.) McAlp. Acacia armata R. Br. Uromyeladium tepperianum (Sacc.) McAlp. Acacia buxifolia A. Cunn. Uromycladium alpinum, McA|lp. Acacia binervata DC. Uromycladium notabile McAlp. Acacia dallachiana F.v.M. Uromyces phyllodiorum (Berk. and Br.) McAlp. Uromycladium alpinum, McAlp. Acacia dealbata Link. Uromyces phyllodiorum (B. and Br.) McAlp. Uromycladium alpinum, McAlp. U. bisporum, McAlp. U. notabile (Ludw.) McAlp. Acacia decurrens Willd. Uromycladium notabile ( Ludw.) McAlp. Acacia diffusa Lindl. Uromycladium tepperianum (Sacc.) McAlp. Acacia elata A. Cunn. Uromyeladium notabile McAlp. Acacia erioclada Benth. Uromycladium tepperianum (Sacc.) MecAlp. (Ludw. ) ( Ludw.) Acacia fasciculifera F. v. M. Uromyces bicinctus, McAIp. Acacia glaucoptera Benth. Uromycladium tepperianum (Sacc.) McAlp. Acacia hakeoides A. Cunn. Uromycladium tepperianum (Sacc.) McAlp. j Acacia implexa Benth. Uromycladium tepperianum (Sacc.) McAIp. U. alpinum, McAlp. Acacia juniperina Willd. Uromyciadium tepperianum (Sacc.) McAlp. Acacia linifolia Willd. Uromycladium alpinum, McAlp. Acacia longifolia Willd. Uromycladium maritimum, McAlp. U. tepperianum (Sacc.) McAlp. Acacia melanoxylon R.Br. Uromycladium robinsoni, MeAlp. Uromycladium tepperianum (Sacc.) McAlp. Acacia microbotrya Benth. Uromyces phyllodiorum (B. and Br.) McAlp. Acacia myrtifolia Willd. Uromycladium tepperianum (Sacc.) MecAlp. Acacia neriifolia A. Cunn. Uromyces fusisporus, Cke. and Mass. U. phyllodiorum (B. and Br.) McAlIp. Acacia notabilis F.v.M. Uromyces phyllediorum (B. and Br.) McAlp. Uromycladium notabile McAlp. Acacia penninervis Sieber. Uromyces phyllodiorum (B. and Br.) McAlp. Acacia pruinosa A. Cunn. Uromyces phyllodiorum (B. and Br.) McAlp. Uromycladium MeAlp. Acacia pycnantha Benth. Uromycladium simplex, McAlp. U. tepperianum (Sace.) MecAlp. Acacia retinodes Schlect. = Acacia neriifolia, A. Cunn. (Ludw.) notabile (Ludw.) Acacia rigens A. Cunn. Uromycladium tepperianum (Sacc.) McAlp. Acacia salicina Lindl. Uromyces fusisporus, Cke. and Mass. Uromycladium tepperianum (Sacc.) McAlp. 33° Acacia siculiformis A. Cunn. Uromycladium tepperianum McAIp. (Sace. ) Acacia spinescens Benth. Uromycladium tepperianum McAlp. (Sacc. ) Acacia stricta Willd. Uromycladium tepperianum McAlp. Acacia verniciflua A. Cunn. Uromycladium tepperianum McAlp. (Sace. ) (Sace.) Acacia verticillata Willd. Uromyeladium tepperianum McAlp. {Sacc.) Acacia vomeriformis A. Cunn. Uromycladium tepperianum McAlp. (Sace. ) Acaena ovina A. Cunn. Phragmidium _ potentillae Karst. (Pers. ) Acaena sanguisorbae Vahl. Phragmidium __ potentillae Karst. (Pers. ) Agropyron divergens Nees. Puccinia graminis, Pers. Agropyron scabrum Beauv. Puccinia agropyri, Ell. and Ev. P. graminis, Pers. Agrostis solandri F.v.M.=Deyeuxia forsteri, Kunth. Alopecurus geniculatus L. Puccinia graminis, Pers. P. perplexans, Plow. Althaea rosea Cav. Puccinia malvacearum, Mont. Alyxia buxifolia R. Br. Puccinia alyxiae, Cke. and Mass. Amphibromus neesii Steud. Puccinia graminis, Pers. Anthoxanthum odoratum L. Puccinia anthoxanthi, Fekl. Aotus villosa Sm. Cronartium jacksoniae, P. Henn. Apium graveolens L. Puccinia thuemeni, McAlp. Apium prostratum Labill. Puccinia thuemeni, McAlp. Host Index. Asperula oligantha F.v.M. (A. scoparia, Hook. f.) Uromyces asperulae, McAlp. Puccinia oliganthae, McAlp. Atriplex semibaccata R. Br. Uromyces atriplicis, McAlp. Avena fatua L. Puccinia graminis, Pers. P. lolii avenae. Avena sativa L. Puccinia graminis, Pers. P. lolii avenae. Beckmannia erucaeformis Host. Puccinia beckmanniae, McAlp. P. graminis, Pers. Bellis perennis L. Puccinia distincta, McAlp. Beta vulgaris L. Uromyces hetae (Pers.) Kuehn. Bidens pilosa L. Uredo bidentis, P. Henn. Boronia spinescens Benth. Puccinia boroniae, P. Henn. Bossiaea cinerea R. Br. Aecidium eburneum, MecAlp. Cronartium jacksoniae, P. Henn. Bossiaea heterophylla Vent. Aecidium eburneum, McAlp. Bossiaea linophylla R. Br. Aecidium eburneum, McAlp. Bossiaea microphylla Sm. Aecidium eburneum, McAlp. Bossiaea prostrata R. Br. Uredo bossiaeae, McAlp. Bossiaea rhombifolia Sieber. Aecidium eburneum, McAlp. Brachycome ciliaris Less. Puecinia brachycomes, McAlp. Brachycome diversifolia Fisch. Mey. Puccinia brachyeomes, McAlp. Brachycome pachyptera Turez. Puccinia brachyeomes, MeAlp. Brachycome scapiformis DC. Puccinia brachycomes, McAlp. Briza minor L. Puccinia graminis, Pers Bromus arenarius Labill. Puccinia bromina, Eriks. and Host Index. Bromus mollis L. Puccinia bromina, Eriks. Bromus racemosus L. Puecinia graminis, Pers. Bromus secalinus L. Puccinia graminis, Pers. Bromus sterilis L. Puccinia graminis, Pers. Brunonia australis Sm. Puccinia brunoniae, McAlp. Bulbine bulbosa Haw. Uromyces bulbinis, Thuem. Burchardia umbellata Rk. Br. Puccinia burchardiae, Sace. Calendula officinalis L. Puccinia calendulae, McAlp. Calocephalus drummondii Benth. Puccinia calocephali, McAlp. Calocephalus lacteus Less. Puccinia calocephali, McAlp. Calotis R. Br. Puccinia calotidis, McAlp Calotis cuneifolia R. Br. Puccinia calotidis, McAlp. Caltha introloba F.v.M. Aecidium calthae, Grev. Candollea serrulata Labill. =Sty- lidium graminifolium, Sw. Canthium (Plectronia) coprosmoides Fv. M. Aecidium plectroniae, Cooke. Carex L. Puccinia longispora, McAlp. Carex alsophila F.v.M. Puccinia caricis (Schum.) Reb. Carex breviculmis, R. Br. Puccinia caricis (Schum.) Reb. Carex caespitosa L. Puccinia longispora, McAlp. Carex gunniana Boott. Puccinia caricis (Schum.) Reb. Carex inversa R. br. Puccinia caricis (Schum.) Reb. Carex paniculata L. Puceinia caricis (Schum.) Reb. Carex pedunculata Muhl. Puccinia caricis (Schum.) Reb. Carex vulgaris Fr. Puccinia longispora, McAlp. Carissa ovata R.Br. Puccinia carissae, Cke. and Mass. Cassia Tourn. Uredo pallidula, Cke. and Mass. Centaurea cyanus L. Puccinia cyani (Schleich.) Pass. Chiloglottis diphylla R.Br Uromyces orchidearum, Cke, Mass. Chiloglottis gunnii Lindl. Uromyces Mass. Chrysanthemum indicum L. Puccinia chrysanthemi, Roze. Cichorium intybus L. Puccinia cichorii (DC.) Bell. Cineraria L. Puccinia cinerariae, McAlp. Clematis aristata R.Br. Caeoma clematidis, Thuem. orchidearum, Cke. 331 and and Puccinia agropyri, Ell. and Kv. I. (Aecidium clematidis DC.). Clematis microphylla DC. Caeoma clematidis, Thuem. Coprosma billardieri Hook. Puecinia coprosmae, Cke. Coprosma hirtella Labill. Puccinia coprosmae, Cke. Correa lawrenciana Hook. Puccinia correae, McAlp. Crepis japonica Benth. Uredo crepidis-japonicae, Lindr, Cruciferae. Puccinia cruciferae, McAlp. Cryptandra hookeri F.v.M. =Spyridium parvifolium, F.v. M. Cymbonotus lawsonianus Gaudich. Aecidium cymbonoti, Thuem. Cynodon dactylon Pers. Puccinia cynodontis, Desm. Cyperus rotundus L. Puccinia cyperi, Arth. Dactylis glomerata L. Puccinia graminis, Pers. Dampiera alata Lindl. Puccinia dampierae, Syd. 332 Host Index. Dampiera stricta R. Br. Puccinia dampierae, Syd. Danthonia DC. Uromyces danthoniae, McAlp. I. Danthonia semiannularis R.Br. Uromyces danthoniae, Mc Alp. II., II. Deeringia celosioides R.Br. Aecidium deeringiae, Cke. and Mass. Deyeuxia forsteri Kunth. (Agrostis solandri F. v. M.) Puccina agrostidis, Plow. Deyeuxia quadriseta Benth. Puccinia graminis, Pers. Dianthus caryophyllus L. Uromyces caryophyllinus (Schrank) Schroet. Dianthus chinensis L. Uromyces caryophyllinus (Schrank) Schroet. Dichondra repens Forst. Puccinia dichondrae, Mont. Diploglottis cunninghamii Hook. f. Uromyces diploglottidis, Cke. and Mass. Distichlis maritima Rafin. Puccinia subnitens, Diet. Echinopogon ovatus Beauv. Puccinia graminis, Pers. Ehrharta stipoides Labill. = Micro- laena stipoides, R.Br. Elymus condensatus Presl. Puccinia impatientis (Schw.) Arth. Elymus striatus Willd. Puccinia graminis, Pers. Elymus virginicus L. Puccinia graminis, Pers. Enchylaena tomentosa R.Br. Puccinia kochiae, Mass. Epilobium Dill. Puecinia _epilobii-tetragoni (DC.) Wint. Epilobium billardierianum Ser. Puccinia _epilobii-tetragoni (DC.) Wint. Epilobium glabellum Forst. Puccinia —_epilobii-tetragoni (DC.) Wint. Erechtites Ratfin. Puccinia erechtitis, McAlp. Erechtites arguta DC. Puccinia erechtitis, McAlp. Erechtites prenanthoides DC. Puccinia erechtitis, Mc Alp. Erechtites quadridentata DC. Puccinia erechtitis, McAlp. Eriostemon myoporoides DC. Puccinia eriostemonis, McAlp. Festuca bromoides L. Puccinia graminis, Pers. Festuca ovina L. Puccinia festucae, Plow. Festuca rigida Kunth. Puccinia festucae, Plow. Geitonoplesium cymosum A. Cunn. Uredo geitonoplesii, McAlp. Geranium pilosum Sol. Puccinia geranii-pilosi, McAlp. Geum renifolium F. v. M. Puccinia gei, McAlp. Glyceria dives F.v. M. Puccinia graminis, Pers. Glyceria stricta Hook. f. Puccinia graminis, Pers. Gnaphalium japonicum Thunb. Puccinia gnaphalii (Speg.) P. Henn. Gnaphalium purpureum L. Puccinia gnaphalii (Speg.) P. Henn. Gompholobium latifolium Sm. Cronartium jacksoniae, P. Henn. Goodenia albiflora Schlecht. Puccinia saccardoi, Ludw. Goodenia geniculata R. Br. Puccinia saccardoi, Ludw. Goodenia glauca F. v. M. Puccinia saccardoi, Ludw. Goodenia hederacea Sm. Puccinia saccardoi, Ludw. Goodenia ovata Sm. Puccinia saccardoi, Ludw. F Goodenia pinnatifida Schlecht. Puccinia saceardoi, Ludw. Goodia lotifolia Salisb. Aecidium soleniiforme, Berk. Haemodorum Sm. : Puccinia haemodori, P. Henn. Host Tvedex. Hakea Schrad. Uredo angiosperma, Thuem. Hardenbergia monophylla Benth. (Kennedya monophylla Vent.) Uromyces hardenbergiae, McAlp. Helianthus annuus L. Puccina helianthi, Schw. Helianthus tuberosus L. Puccinia helianthi, Schw. Helichrysum Vaill. Puccivia kalchbrenneri, De Toni. Hibbertia sericea Benth. Puecinia hibbertiae, McAlp. Hibiscus L. Puccinia heterospora, B. and C. Hordeum murinum L. Puceinia graminis, Pers. Hordeum secalinum Schreb. Puccinia graminis, Pers. Hordeum vulgare L. Puccinia graminis, Pers. P. simplex (Koern.) Eriks. and Henn. Hypericum japonicum Thunb. Melampsora hypericorum (DC.) Schroet. Aecidium disseminatum, Berk. Hypochoeris glabra L. Puceinia hypochoeridis, Oud. Hypochoeris radicata L. Puecinia hypochoeridis, Oud. Hypoxis glabella R. Br. Puccinia hypoxidis, McAlIp. Jacksonia scoparia R. Br. Cronartium jacksoniae, P. Henn. Juncus effusus L. Pueccinia juncophila, Cke and Mass. Juncus maritimus Lam. . Puccinia juncophila, Cke and Mass. Juncus pallidus R. Br. Puccinia juncophila, Cke and Mass. Juncus paucifiora R. Br. Puccinia juncophila, Cke and Mass. Kennedya monophylla, Vent. = Har- denbergia monophylla, Benth. Kochia sedifolia F. v. M. Puccinia kochiae, Mass. Kochia villosa Lindl. Puccinia kochiae, Mass. Lactuca L. Puccinia prenanthis (Pers.) Lindr. 333 Lagenophora billardieri Cass. Puccinia lagenophorae, Cke. Lagenophora huegelii Benth. Puccinia lagenophorae, Cke. Lavatera plebeia Sims. Puccinia malvacearum, Mont. Leschenaultia linarioides DC. Puccinia gilgiana, P. Henn. Limnanthemum indicum Thw. Aecidium nymphoidis, DC. Limosella aquatica L. Uromyces limosellae, Ludw. Linum marginale A. Cunn. Melampsora lini (Pers.) Tul. Linum usitatissimum L. Melampsora lini (Pers.) Tul. Lobelia anceps L. Puccinia aucta, Berk. and F. v. M. Lobelia pratioides Benth. Puccinia aucta, Berk. and F. v. M. Lobelia purpurascens R. Br. Puccinia aucta, Berk. and f. v. M. Lolium perenne L. Puccinia lolii, Niels. Loranthus celastroides Sieber. Puccinia loranthicola, McAlp. Luzula campestris DC. Puccinia tenuispora, McAlp. Luzula oldfieldii Hook. f. Puccinia tenuispora, McAlp. Malva rotundifolia L. Puccinia malvacearum, Mont. Malva sylvestris L. Puccinia malvacearum, Mont. Mentha laxiflora Benth. Puccinia menthae, Pers. Mentha pulegium L. Puccinia menthae, Pers. Microtis porrifolia R.Br. Uromyces microtidis, Cke. Microlaena stipoides R.Br. (Hhrharta stipotdes Labill.) ‘Uromyces ehrhartae, McAlp. Muehlenbeckia adpressa Meissn. Puccinia muehlenbeckiae (Cke.) Syd. Muehlenbeckia cunninghami Fv. M. Uromyces politus (B. and Br.) McAlp. 334 Host Index. Muehlenbeckia gracillima Meissn. Puccinia muehlenbeckiae (Cke.) Syd. Olearia argophylla F. v. M. (Aster). Puccinia oleariae, McAlp. Olearia axillaris F.v.M. Aecidium oleariae, McAlp. Opercularia aspera Gaertn. Puccinia operculariae (Morr.) Syd. Opercularia varia Hook f. Puccinia operculariae (Morr.) Syd. Pelargonium australe Jacq. Puccinia morrisoni, McAlp. Phalaris canariensis L. Puccinia graminis, Pers. Phalaris minor Retz. Puccinia graminis, Pers. Phragmites communis Trin. Puccinia magnusiana, Koern. P. tepperi, Ludw. Plagianthus sidoides Hook. Puccinia plagianthi, McAlp. Plagianthus spicatus Benth. Puccinia malvacearum, Mont. Plantago varia R. Br. Aecidium plantaginis-variae, McAlp. Platylobium formosum Sm. Aecidium platylobii, McAlp. Cronartium jacksoniae, P. Henn. Plectronia coprosmoides = Canthium coprosmoides, F. v. \ Poa annua L. Puccinia poarum, Niels. Poa caespitosa Forst. Puccinia poarum, Niels. Poa pratensis L. Puccinia poarum, Niels. Podolepis longipedata A. Cunn. Puccinia podolepidis, McAlp. Polygonum aviculare L. Uromyces polygoni, Fckl. Pomaderris apetala Labill. Uredo spyridii, Cke. and Mass. Pratia erecta Gaudich. Puccinia aucta, Berk. and F. v. M. Pratia pedunculata Benth. Puccinia aucta, Berk. and F. v. M. Pratia platycalyx Benth. Puccinia aucta, Berk. and F. v. M. Prunus amygdalus Stokes. Puccinia pruni, Pers. Prunus armeniaca L. Puccinia pruni, Pers. Prunus domestica L. Puccinia pruni, Pers. Prunus persica Stokes. Puccinia pruni, Pers. Ranunculus L. Aecidium ranunculacearum, DC. Ranunculus gunnianus Hook. Aecidium ranunculacearum, DC. Ranunculus lappaceus Sm. Aecidium ranunculacearum, DC. Ranunculus parviflorus L. Aecidium ranunculacearum, DC. Ranunculus rivularis Banks and Sol. Aecidium ranunculacearum, DC. Rhagodia billardieri R.Br. Uredo rhagodiae, Cke. and Mass. Rosa canina L. Phragmidium subcorticium (Schrank) Wint. Rosa laxa Retz. Phragmidium subcorticium (Schrank) Wint. Rosa rubiginosa L. Phragmidium subcorticium (Schrank ) Wint. Rottboellia compressa L. Puccinia cacao, McAlp. Rubus moluccanus L. Phragmidium longissimum, Thuem. Rubus parvifolius L. Phragmidium barnardi, Plow. and Wint. Ruellia australis Cav. Puccinia mussoni, McAlp. Rumex brownii Campd. Puccinia ludwigii, Tepp. Host Index. Rumex fiexuosus Sol. Puccinia ludwigii, Tepp. Saccharum officinarum L. Uredo kuehnii, Krueg. Scaevola L. Uromyces puccinioides, Berk. and F. v. M. Schelhammera undulata R. Br. Uredo schelhammerae, McAlp. Scirpus nodosus Rottb. Uredo scirpi-nodosi, McAlp. Scleranthus diander BR. Br. Uromyces scleranthi, Rostr, Scorzonera angustifolia L. Puccinia angustifoliae, McAlp. Secale cereale L. Puccinia graminis, Pers. Selliera radicans Cav. Uromyces puccinioides, Berk. and F. v. M. Senecio brachyglossus F. v. M. Puccinia tasmanica, Diet. Senecio pectinatus DC. Puccinia tasmanica, Diet. Senecio velleioides A. Cunn. Puccinia tasmanica, Diet. Senecio vulgaris L. Puccinia tasmanica, Diet. Sorghum halepense Pers. Puccinia purpurea, Cke. Sorghum vulgare Pers. Puccinia purpurea, Cke. Sporobolus indicus R. Br. Uromyces tenuicutis, McAlp. Spyridium parvifolium F. v. M. (Cryptandra hookeri F. v. M.) Uredo spyridii, Cke and Mass. Stellaria media Cyrill. Puccinia arenariae (Schum.) Schroet. Stipa flavescens Labill. Puccinia flavescentis, McAlp. Stipa semibarbata R. Br. Puecinia flavescentis, McAlp. Stylidium graminifolium Sm. (Can- dollea serrulata Labill.) Puccinia stylidii, McAlp. Tabernaemontana orientalis R. Br. Caeoma apocyni, McAlp. Tetragonia implexicoma Hook. f. Puccinia tetragoniae, McAlp. Thelymitra antennifera Hook. f. Uromyces thelymitrae, McAlp. Thelymitra flexuosa Endl. Uromyces thelymitrae, Mc Alp. Threlkeldia drupata Diels. Puccinia dielsiana, P. Henn. Tillaea sieberiana Schult. Uredo tillaeae, McAlp. Tremandra stelligera R. Br. Puccinia pritzeliana, P. Henn. Tricoryne elatior R. Br. Uromyces tricorynes, McAlp. Trifolium repens L. Uromyces trifolii (Alb. and Schw.) Winter. Triticum polonicum L. Puccinia graminis, Pers. P. triticina, Eriks. Triticum vulgare Vill. Puccinia graminis, Pers. P. triticina, Eriks Urtica dioica L. Puccinia caricis (Schum. ) (decidium urticae Schum.) Reb. Velleia macrocalyx De Vriese. Puccinia saccardoi, Ludw. Velleia paradoxa R. Br. Puccinia saccardoi, Ludw. Veronica L. Aecidium veronicae, Berk. Veronica calycina R. Br. Aecidium dise.forme, McAlp. Veronica gracilis R. Br. Aecidium disciforme, McAlp. Vicia faba L. Uromyces fabae (Pers.) De Bary. Vigna catjang Walp. Uromyces appendiculatus (Pers.) Link. Viola betonicifolia Sm. Puccinia hederaceae, McAlp. 335 Me 336 Host Index. Viola hederacea Labill. Zea mays L. Puccinia hederaceae, McAlp. Puccinia maydis, Bereng. Vittadinia anetrale aie Zornia diphylla Pers. ncn es Ae mates Ee Puccinia zorniae (Diet.) McAlp. Wurmbea dioica F.v.M. : 98 Puccinia wurmbeae, Cke. and Mass. Zygophyllum billardieri si Uredo anguillariae, Cooke. Uromyces vesiculosus, Wint. Xanthosia pusilla Bunge. Zygophyllum glaucescens F.v.M. Puccinia xanthosiae, McAlp. Uromyces vesiculosus, Wint. Fungus Index. 337 FUNGUS INDEX. Synonyms in italics ;, * Species excluded from Australia ; + Doubtful species. PAGE. Aecidium Pers. ... at & =o = Ri he ... 194 *apovyni, Schwein. (See Caeoma apocyni, McAlp., p. 193) et so. 209 *barbareae, DC. (See Puccinia cruciferae, McAlp., p. 184) one wae 209 *bellidis, Thuem. (See Puccinia distincta, McAlp., p. 156) a Rape 2 bossiaeae, P. Henn. = Aecidium eburneum, McAlp. 455 Sa sen LOS calendulae, McAlp.=Puccinia calendulae, McAlp. Pe me soeeelen calthae, Grev.—Caltha introloba ae ee . 2ZOL clematidis, DC. = Puccinia agropyri, Ell. & Ey. I. ee sa) TS *compositarum, Mart. (See Puccinia tasmanica, Diet., p. G3) cee sos) 209 eymbonoti, Thuem.--Cymbonotus lawsonianus ... Ges oe LOG cystoseiroides, Berk. = Puccinia operculariae (Morr.) Syd. I. np soe GG deeringiae, Cke. and Mass.—Deeringia celosioides ae ae » 200 disciforme, McAlp.—Veronica calycina, V. gracilis 5A Bae x. le disseminatum, Berk.—Hypericum japonicum .. zs 200) eburneum, McAlp. —Bossiaea cinerea, B. heterophylla, B. linophylla, B. microphylla, B. rhombifolia e 198 goodeniacearum, Berk. = Uromyces puccinioides, Berk. & F. v.M. Ls and Puccinia saccardoi, Ludw. I. "p ae 91, 147 impatientis, Schw. = Puccinia impatientis (Schw. ) Arth. 2 ee 2 2s. lobeliae, Thuem.= Puccinia aucta, Berk. & F.v.M. J. ... ae a. | SS microstomum, Berk. = Puccinia aucta, F.v.M. I. Bas aoe seo) AS monocystis, Berk.-—Abrotanella forsterioides ... or ers veo LO nymphoidis, DC.—Limnanthemum indicum _... eae eee se, LOG oleariae, McAlp.—Olearia axillaris “iss sis iis ae sees oa perkinsiae, P. Henn.=P. gilgiana, P. Henn. I. i aes note LeeGs *plantaginis, Ces. (See A. plantaginis-variae, McAlp., b- 195) tee goo PAU plantaginis-variae, McAlp.—Plantago varia __... , ass ic. ato platylobii, McAlp.—Platylobium formosum _... bo ass aes) 199 plectroniae, Cke.—Canthium (Plectronia) coprosmoides a races HOS ranunculacearum, DC.—Ranunculus sp., R. guunianus, R. lappaceus, R. parviflorus, R. rivularis ... 5 pony UT *senecionis, Desm. (See Puccinia tasmanica, Diet., sap: 163), i ... 209 soleniiforme, Berk.—Goodia lotifolia . , ae Sore urticae, DC.=Puccinia caricis (Schum.) Reb. iia Geis Re 560 USB veronicae, Berk.—Veronica sp. Bee wa IGE *violae, Schum. (See Puccinia hederaceae, Me Alp., p. 183) ah a», 209 vittadiniae, McAlp. = Puccinia vittadiniae, McAlp. ‘ Ae << GS Caeoma Link ... RS: a we ¥ st BEN saat kOe apoeyni, McAlp.—T Senate orientalis He ae sant LOS ciematidis, Thuem. - Clempasis aristata, C. microphylla ... aa sop n Oe Cronartium Fr. ... Ze Se aes at) SO *asclepiadeum ( Willd.) pee (See C. eee P. Henn., p. 190) a 20S jacksoniae, P. Henn.—Jacksonia scoparia, Aotus villosa, Bossiaea cinerea, Gompholobium latifolium, Platylobium formosum ... oe Pepe AW) Hamaspora Koern. longissima, Koern.=Phragmidium longissimum, Thuem. ia cg 7 Melampsora Cast Bi i ove me ca ray a9) hypericorum (DC.) Schroet. anne ceva japonicum was Ser PO lini (Pers.) T'u).—Linum marginale, L. usitatissimum. (Introduced.) bev, 292 +nesodaphnes, Berk. and Br. Probably a Hyphomycete ... a .. 208 phyllodiorum, Berk. and Br. eral ea a (B. and Br.) McAlp. one =) ex ee To ae 338 Fungus Index. PAGE. Phragmidium Link bes oe us Ae ef oh a barnardi, Plow. and Wint.—Rubus parvifolius aes ae oe 186 longissimum, Thuem.—Rubus moluccanus Ss oe ue aod potentillae (Pers.) Karst.—Acaena ovina, A. sanpuisorba oe we subcorticium (Schrank) Wint.—Rosa canina, R laxa, R. rubiginosa. (Introduced). at are oe a aise oe jon Puccinia Pers. 2 vis oe PY a” ae te 12 “acetosae (Schum.) eile. (See P. ludwigii, Tepp. p. 174) Bh dis, scene *aegra, Grove. (See P. hederaceae, McAlp., p. 183) .. 208 agropyri, Ell and Ev.—Axgropyron scabrum Diy Lele Clematis aristatal. 113 agrostidis, Plow. —Deyeuxia forsteri ... se pmb altera, McAlp.=P. cynodontis, Desm. ... Ae ae Biss in. 1S alyxiae, Cke. and Mass.—Alyxia buxifolia ... ¥y sa dist (Eas angustifoliae, McAlp.—Scorzonera augustifolia as aa ay Loe anthoxanthi, Fckl.—Anthoxanthum odoratum, (Introduced.) ... “wet LED *apii, Desm. (See Puccinia thuemeni, McAlp., p. 168) .. a ace 208 arenarise (Schum.) Schroet.—Stellaria media. Gridecaseaas | em ee 177 aucta, Berk. and F.v.M.—Lobelia anceps, L. pratioides, L. purpurascens, Pratia erecta, P. pedunculata, P. platycalyx 148 beckmanniae, McAlp.—Beckmannia erucaeformis. (Introduce ) nob Lae berkeleyana, De Toni= P. dichondrae, Mont. ... : See a! VL boroniae, P. Henn.—Boronia spinescens 181 brachycomes, McAlp.—Brachycome sai: B. div ersifoli, B pachyptera, B. scapiformis ... or 150 bromina, Eriks.—Bromus arenarius, . mollis ba eae Bi 1&2 7LIG brunoniae, McAlp.—Brunonia Seen a Ane Pe ois, oe bucchardiae, Sace.—Burchardia umbellata see ea ae «. 13s cacao, McAlp.—Rottboellia compressa af “pt eat xo vt SAD calendulae, McAlp.—Calendula officinalis oes con VLG calocephali, McAlp.—Calocephalus drummondii, C. lacteus a aot ER colotidis, McAlp.—Calotis sp.,C cuneifolia — ... ep wih SH earicis (Schum.) Reb. —Carex alsophila, C. brev iculmis, C. gunniana, C. inversa, C. paniculata, C. pedunculata, II., III. ; Urtica dioical. ... 138 carissae, Cke. and Mass.—Carissa ovata ue ate .. 144 castagnei, Thuem. =P. thuemeni (Thuem.) McAlp. Fa a ecu LGR *caulincola, Cda. (See P. hypochoeridis, Oud., p. 159.)... .-- 208 chrysanthemi, Roze—Chrysanthemum indicum. (Intr oduced. 2 Jee!) Ceo cichorii (DC.) Bell.—Cichorium intybus. (Introduced.)... oa .. 154 cinerariae, McAlp.—Cineraria sp. cult. sie BAS 20) Lee coprosmae, Cke. — Coprosma billardieri, C. hirtella ... pee .. 165 coprosmatis, Morr. = P. coprosmae, Cke. “Se ee Hep Hee wi hil coronifera, Kleb. =P. lolii, Niels. pep ae si Pes: ee ie correae, McAlp.—Correa lawrenciana Aas ous “fae = SoG cruciferae, Mealp. — Crucifer unknown are ~ a oe eyani (Schleich.) Pass. —Centaurea cyanus. (Introduced.) ... cae ene cynodontis, Desm.-—Cynodon dactylon Sot fi nee --a) RES cyperi, Arth.—Cyperus rotundus “6 ee ee sie xan dampierae, Syd.—Dampiera alata, D. stricta... a a ses dichondrae, Mont.—Dichondra repens, oe eb ine ee dielsiana, P. Henn.—Threlkeldia drupata, Diels. ~~ ae *dispersa Eriks. (See P. bromina, Eriks. and P. triticina, Eriks.)... 116, 132 distincta, Mc Alp.—Bellis perennis oe epilobii-tetragoni (DC.) Wint —- Epilobiuin sp., EK. billardieranuim, E. glabellum 170 erechtitis, McAlp.— Erechtites Sp. BE. ar guta, E. prenanthoides, 'E. quad- ridentata : ee aa ea eriostemonis, MeAlp. —E riostemon my roporoides we nee tis | festucae, Plow.—-Festuca ov ina, F. rigida. (Introduced, ) ws a. flay rescentis, McAlp.—Stipa flavescens, S. semibarbata ges 195). gel, McAlp.—Geum renifolium << =e ce SO “geranii, Corda —(See P. morrisoni, ‘McAlp., p. 180 a wis [ii pee geranii-pilosi, McAlp.—Geranium pilosum “4 os sc VAD gilgiana, P. Henn.— Leschenaultia linar ioides. oo oa gnaphalii, (Speg.) P. Henn.—Gnaphalium japonicum, G. ‘purpureum ie gnaphaliicola, P. Henn. =P. gnaphalii (Speg.) P. Henn. Pz .. 158 Fungus Index. 339 , PAGE, Puccinia Pers.—continued. graminis, Pers.—Agropyron divergens, A. scabrum, Alopecurus geniculatus, Amphibromus neesii, Avena fatua, A. sativa, Beckmannia erucae- formis, Briza minor, Bromus racemosus, B. secalinus, B. sterilis, Dactylis glomerata, Deyeuxia quadriseta, Echinopogon ovatus, Elymus striatus, K. virginicus, Festuca bromoides, Glyceria dives, G. stricta, Hordeum murinum, H. secalinum, H. vulgare, Phalaris canariensis, P. minor, Secale cereale, Triticum polonicum, T. vulgare. (Introduced.) see, DLZO haemodori, P. Henn.—Haemodorum sp. age ae fon UG hederaceae, McAlp.—Viola betonicifolia, V. hederacea a =e Me cs: helianthi, Schwein.—Helianthus annuus, H. tuberosus. (Introduced.) ... 158 heterospora, Berk. and Curt. —Abutilon avicennae, A. crispum, Hibis- cus sp. .. oe ae a8 sss ee ey hibbertiae, McAlp. —Hibbertia s sericea : ae 50) PLSD hypochoeridis, Oud.—Hypochoeris glabra, H. radicata. (Introduced. ers, AUR! hypochoeridis, McAlp.—(P.macalpini, Syd.) =P. lagenophorae, Cke. so7 GH hypoxidis, McAlp.—Hypoxis glabella ... me RD impatientis, (Schw.) Arth.—Elymus condensatus. (Introduced. ei apn) IB: *investita, Schw.—(See P.gnaphalii (Speg.) P. Henn. sc eocelas juncophila, Cke. and Mass.—Juncus effusus, J. mar itimus, J. pallidus Be ae kalchbrenneri, De Toni —Helichrysum sp... 5.) LGD kochiae, Mass. —Enchylaena tomentosa, Kochia sedifolia, K. villosa <1 G lagenophorae, Cke.—Lagenophora billardieri, L. huegelii oo LOL lolii, Niels.—Avena fatua, A. sativa, Lolium perenne. (Introduced. ) 123 longispora, McAlp.—Carex sp., C. caespitosa, C. vulgaris occ sean lide loranthicola, McAlp.—Loranthus celastroides ... SS os Bra / ludwigii, Tepp.—Rumex brownii, R. flexuosus... a -5- snes LAE macalpini, Syd. =P. lagenophorae, Cke. ae 5 soe magnusiana, Koern.—Phragmites communis... 125 malvacearum, Mont. —Althaea rosea, Lavatera a Malv a ratindiiolia: Plagianthus spicatus. ( Introduced.) = . es ae C198 maydis, Bereng.—Zea mays. (Introduced.) ... Soo = AP menthae, Pers.—Mentha laxiflora, M. pulegium. (Introduced.)... -- 140 microseris, McAlp.=P. hypochoeridis, Oud. _... sc ae sog GE) morrisoni, McAlp.—Pelargonium australe .-- 180 muehlenbeckiae (Cke.) Syd.— Muehlenbeckia adpressa, \ M. [. gracillima Sao munita, Ludw.=P. dichondrae, Mont. a5 ics JAZ mussoni, McAlp.—Ruellia australis... ea aes isi ves, 24 nigricaulis McAlp. =P. saccardoi, Ludw. i an soc S, elaT oleariac, McAlp.—Olearia argophylla ... se se ae se, M205 oliganthae, McAlp.—Asperula oligantha <6 : Be wn ¥lGs operculariae (Morr.) Syd.—Opercularia aspera, O. varia mae a. L6G perplexans, Plow.—Alopecurus geniculatus ... a LET *phragmitis (Schum.) Koern.—(See P. magnusiana, Koern, p- 125) ... 208 plagianthi, McAlp.—Plagianthus sidoides cae AS poarum, Niels.—Poa annua, P. caespitosa, P. pratensis. “Introduced. ) ui ZS podolepidis, McAlp. —Podolepis longipedata ... me ssc ae Loe prenanthis (Pers.) Lindr.—Lactuca sp. (Introduced.) ... eae GZ pritzeliana, P. Henn.—Tremandra stelligera _... 182 pruni, Pers.—Prunus amygdalus, P. armeniaca, P. domestica, P. persica, (Introduced.) ... son, ial purpurea, Cke.—Sorghum halepense, | iS vulgare. (Introduced.) eee 129 *rimosa, Link.—(See Uredo scirpi-nodosi, McAlp., p. 203) aoe 20s *rumicis, Lasch.—(See P. ludwigii, Tepp., p. 174) ... 208 rumicis-scutati var. muehlenbeckiae, Cke. a mueblenbeckiae (Cke. ) Sydiwe-se lao saccardoi, Ludw. — Goodenia albiflora, G. geniculata, G. glauca, G. hederacea, G. ovata, G. pinnatifida, Velleia macrocalyx, V. paradoxa ... 147 simplex (Koern. ) Eriks. and Henn.—Hordeum vulgare. (Introduced) ... 130 sorghi Schw. =P. maydis, Bereng., and P. purpurea, “Cke. spear: - 127, 129 stylidii, MeAlp.---Stylidium graminifolium cae ae sean 204: subnitens, Diet.—Distichlis maritima ... Se etlsiil tasmanica, Diet. — Senecio brachyglossus, S. " pectinatus, S. velleioides, S. vulgaris a sat .- 163 eaaienira. McAlp. —Luzula campestris, L. oldfieldii ... ae Peeks 7 tepperi, Ludw.—Phragmites commuuis.. : x i: soo lis tetragoniae, McAlp.—Tetragonia implexicoma pes LTS thuemeni, McAlp.—Apium graveolens. A. prostratum. ‘Introduced. )ios.. 168 triticina, Eriks.—Triticum vulgare. (Introduced.) ie ome ema (37 340 Fungus Index. pee ; PAGE, Puccinia Pers.—continued. *violae, (Schum.) DC.—(See P. hederaceae, sad het aches ue ale oo + Se vittadiniae, McAlp.—Vittadinia australis oa bes, ee hee wurmbeae, Cke. and Mass. —Wurmbea dioica... ae aad . 138 xanthosiae, McAlp.—Xanthosia pusilla sie ads sg anaes zorniae (Diet.) McAlp.—Zornia diphylla ae. a Hes pclganiies Uredo Pers. #3 as ef Fe Ad ivi) SO angiosperma, Thuem. Sette o sp. apt B= ee anguillariae, Cke.—Wurmbea dioica : 5 «-- 203 armillata, Ludw. = Puccinia juncophila, Cke. and Mass. aoe BO. bidentis, P. Henn.—Bidens pilosa Re re Jt eae! bossiaeae, McAlp.—Bossiaea prostrata se: ~~. 20e *cichoracearum, DC.—(See Uredo bidentis, P. Hens p. 204) ih fe clematidis, Berk. =Caeoma clematidis, Thuem. Bis i. shee crepidis-japonicae, Lindr.—Crepis japonica ’ Aas Se. 43. Doe chrhartae, McAlp. = Uromyces ehrhartae, McAlp. ae aoe 54°! be geitonoplesii, McAlp —Geitonoplesium cymosum ae oe ss OS gnaphalii Speg. = Puccinia gnaphalii (Speg.) P. Henn. ... yess am oo «xuehnii, Krueg.—Saccharum officinarum. (Introduced.) die ... 202 *Jeguminum, Desm.—Acacia sp. ies i. 20D notabilis, Ludw. = Uromycladium notabile (Ludw. ) Mealp, ee 5-5 108 pallidula, Cke. and Mass —Cassia sp. .. “a -» 206 rhagodiae, Cke. and Mass.—Rhagodia billardieri =r ee peo ae rottboelliae, Diet. = Puccinia cacao, McAlp. oe we i sor ghaal schelhammerae, McAlp.—Schelhammera undulata me goo. lee scirpi-nodosi, McAlp.—Scirpus nodosus as oe bes 5. mae sorghi, Fckl. = Puccinia purpurea, Cooke. soe --. 129 spyridii, Cke. and Mass.—Pomaderris apetala, Spyridium parvifolium ... 204 tillaeae, McAlp.—Tillaea sieberiana ... : oc Bat ... 206 Uromyces Link ... ay ras ve a2) *amygdali, Pass. (See Budeininh pruni, —_ p- 171) ve Cte 7 appendiculatus, (Pers.) Link —Vigna catjang. _ (Introduced. NS th by asperulae, McAlp — Asperula oligantha + we asteris, MeAlp. = Uredo dubia, McAlp... ae eis wd tea, OO atriplicis, Mc Alp. —Airiplex semibaccatum —... eae zi L<. 200 betae (Pers.) Kuehn.—Beta vulgaris. yee Ti ) a Se hos OD bicinctus, McAlp.—Acacia fasciculifera mae we ey: (>. bulbinis, Thuem.—Bulbine bulbosa we aT Site a7! car yophyllinus (Schrank) Schroet.—Dianthus caryophyllus, D_ chinensis. (Introduced.) DHE. wet i foc, A danthoniae, McAlp. —Danthonia sp., D. semiannularis ... é, bats digitatus, Wint. = Ur omyces phyllodiorum (B. and Br. ) McAlp. . 2 wan diploglottidis, Cke. and Mass.—Diploglottis cunninghamii uP Pe OL ehrhartae, McAlp —Microlaena (Hhrharta) stipoides ... iA tii 386 fabae (Pers. ) De Bary.—Vicia faba, (Introduced.) “A ae &. “38 fusisporus, Cke. aod Mass.—Acacia neriifolia, A. salicina By Ser AOE hardenbergiae, McAlp — Hardenbergia (Kennedya) monophylla _.. .. 94 *junci (Desm.) Tul.—(See Puccinia juncophila, Cke. and Mass. i 136. 3. ae kuehnii, Krueg =Uredo kuehnii, Krueg. E --. 202 limosellae, Ludw.—Limosella aquatica... See Nis oe a: ins _ 88 microtidis, Cke —Microtis porrifolia — a8 fin SSS orchidearum, Cke. and Mass —Chiloglottis diphylla, C. gunnii ae t.. 189 phaseoli (Pers.) Wint.=Uromyces appeadiculatus (Pers.) Link. ... =. $92 phyllodiae, Cke. and Mass. = Uromyces phyllodiorum (B. and Br.) McAlp. 95 phyllodiorum (B. and Br.) McAlp.—Aecacia sp., A. dallachiana, A. micro- botrya, A. neriifolia, A notabilis, A. penninervis, A. pruinosa a. We politus (Berk) McAlp.—Muehlenbeckia cunninghami _... ad a. polyenemi, McAlp.—Polycnemum pentandrum ... a ie ty: polygoni (Pers.) Fckl.—Polygonum aviculare. (introduced. ) oe = 9 puccinioides, Berk. and F. v. M.—Selliera radicans, Scaevola sp. bus scleranthi, Rostr.—Scleranthus diander a ia as co es tenuicutis, McAlp.—Sporobolus indicus a ws Or tepperianus, Sace. = Uromycladium tepperianum (Sace. ) McAlp. ie ws | AOD thelymitrae, McAlp —Thelymitra antennifera, T, flexuosa ive Cw tricorynes, McAlp.—Tricoryne elatior ... Xe sae awe OD trifolii (Alb. and Schw.) Wint.—Trifolium repens. (Introduced. ) tos vesiculosus, Wint.—Zygophyllum billardieri, Z. glaucescens i < ee Fungus Index. peeecladiam McAlp. alpinum, McAlp.—Acacia panitolia, A. datlachiang A. dealbata, a imple, A. linifolia ee “e . : bisporum, McAlp. —Acacia dealbata ay: 8 ax maritimum, McAlp.—Acacia longifolia notabile (Ludw.) McAlp.—Acacia binervata, A. ‘dealbata, A. decurrens, A elata, A. notabilis, A. pruinosa ae vas Ser # robinsoni, McAlp.—--Acacia melanoxylon simplex, McAlp.—Acacia pyenantha ... ws Bae — oe tepperianum (Sacc.) McAlp.—Acacia armata A. diffusa, A. erioclada, A. glaucoptera, A. hakeoides, A. implexa, A. juniperina, A. longifolia, A. melanoxylon, A. myrtifolia, A. pycnantha, A. rigens, A. salicina, A. siculiformis, A. spinescens, A. stricta, A. verniciflua, A. verticillata, A. vomeriformis ... Eee 111 oii yO isa) si os Awe oe 7. f | Os ule a ot a La My cf a is ‘ ( Bi rs a ‘ x 4 a oa? é : ‘ iin Wigan Pai #4 lah vygd re ce soli marty 24 Pion vent ' Mwy Syste! " , : ' se 7 ¥ j ig “he ao ae Cmgsl Mi) nae ied Gol Big a, ¥ via i bid Mogeien Ligaeyt ainaeds s(t ah i ‘ pA ia vain we sd wa ee Ae souevrds ie thin ¢ '; Salk hae Aanmtayyrels niidadiwe ry nl hit Pea wr iv “ailgatinetomt whver) he ath a mite vac seal aitinentey sich — pf Aull rT Dt A Abin ag “aie Ins G von 100 ee : A Lali ant oH . 438 My rte Oe me A Mero mys wa det rinse an ah als a 4) Sa Whi i { elma Y ai , j ‘ a v 7 i ig Aah . . ‘ ‘ % 7; yl , ; } z a: ’ é ee | 4 /* \ b j ‘] i ha u wh ; 2 vo fe ae f + Y bs os oe Jue i ; th “ P why iid lif A dey a 1 ea ape O a | i aie, 2s clyat Wing 7 Dee || } i] 4 aig uy ee Ly. 5 ' a “ iP ry ib 4 + a i Ww a 7 S re i a ; t 4 Dae ‘ a : x ; eel A 7 ‘ ‘ ‘a J ar Ly it i ‘git Anta tel iwy w wy ~ j a ' note Iwigo (AP ” ae Me Aly ye as rh Yh. aetbe a et eh A J (rah West , » ia i he {ue Cortada (eriyal aay, Vit eet, es) Oe al ! i - » General Index. GENERAL INDEX. PAGE. Acacia, gall fungi 5 Kangaroo 6 Acacia armata 6 dealbata 6 decurrens 6 implexa 6 pycnantha 6 salicina : 6 Aecidiospores, binucleate ft 14 coloured membrane in Gymno- sporangium se 16 colouring matter 16 development athe 17 distinction from uredospores 36 germination in Puccinia tasmanica 16 infection af 16 origin 5 ain atsel CFS Ic1D partaking ‘of character of teleutospores 37 repeated formation.. 18 retention of germinating power . ss 16 Aecidium, colour 16 development one 17 invigorating power 17 in heteroecious Ec 58 on grass... i . 18, 57 on seeds 4 4 70 origin oe as sod fe ZAE paraphyses 22, 36 peridium ... 17 primary and secondary 18 pseudoperidial cells + 17 repeated formation 18 sterile cells an bee 16 sexuality 145175, 75 Aecidium abietinum ... = 56 bellidis 209 berberidis, spore g germination 16 importatum 61 platylobii, mycelium in peed 70 Algae 40 Alopecurus pratensis with Puc- cinia graminis 68 Amphispore ... 25 germination : ots 25 Anagallis arvensis, importation 43 Anchusa 08s 90 Anthomyces . 84. Apium, graveolens (Puccinia) 42 prostratum (Puccinia) 42 Appressorium 3 Asclepiateae, Cr onartium 53 Ascomycetes ash 40 Asparagus rust (Puceinia aspar- agi), distributed by wind 7 water relation 9 Atmospheric influences on spore germination 10 Auriculariaceae fal 32 Australian rusts, number aes 50 distribution 51 438, M 343 PAGE. Autoecious species -- LO, 55 most numerous 45 repetition of aecidia chic 18 Avena elatior with Puccinia graminis 68 Baeodromus ... 33 Barberry, connexion ie witeat rust 5, 58 in Australia Es 66 infection experiments, local. 66 in Kew gardens 68 Barberry rust (Aecidium ber- beridis) .. : 16 absent in Australia. 66 connexion with wheat rust . 55 increasing vigor of wheat rust 58 local attempts at inoculation 66 Barclayella «+. sor ee 33 Basidia in aecidia oe eee 16 Basidiomycetes 40 Bean rust (Uromyces fabae) 20 ” Beckmanniaerucaeformis, importa- tion of rust on seed — 43 Beet rust (Uromyces betae) 84 Binucleate spores aoe 14 Biologic forms, and classification 79 evolution of Bae see 54 Bismarck brown 12 Black wattle gall fungus (Uro- mycladium notabile) eit 6 Brachypuccinia 11 Bremia lactuea, effect of copper salts sce rr 63 Bridging species soe aes 53 Brome rust (Puceinia bromina) ... 3 infection by uredospores 3 starvation of host . 60 uninfluenced by structural peculiarities of leaf 61 Brown Rust (Puccinia dispersa) ... 79 Burning stubble, effect on wheat iavisin "Sao ts nich 72 Caeoma Bae 1 eeaG Caeomospores .. 36 Carnation rust (Uromyces car yo- phyllinus) 85 Caustic potash for softening tissues 12 Cecidomyia, eating rust spores fi Cedar apples osc 6 Celery rust (Puccinia thuement) .. 42 Cereal rusts not liable to affect other. cereals indiscrimin- ately ... ses 53 Cvcactanie parasitism. due to positive and negative _... 52, 62 Chickweed rust (Puceinia aren- ariae) dak 42 Chicory rust (Puccinia cichorii) . 42 Chrysanthemum rust (Puccinia chrysanthemi) bbs adh 21 germination of uredospores 21 importation oe nee 45 344 PAGE. Chrysomyxa, absence of fir trees 58 germination of teleutospore 34 origin of species in Alps... 56 uredospores in chains 19 Chrysomyxa, abietis ... ase 56 ledi eee oe 56 rhododendri 56 Ohrysopsora, teleutospore of ex- ceptional form 32 Classification and biologic forms of Uredines ; si 79 Clover rust (Uromyces trifolii) ««- 18, 84 Cluster cups are bn 16 Coleosporiaceae 82 Coleosporium, function of paraphyses 30 teleutospore in 32 uredospores in chains 19 Colecsporium senecionis, and fir trees 58 ae fertilisation in 37 Compositae, native rusts on 45 Compound teleutospores 24 Copper salts, influence on fungi... 62 Cronartiaceae . 82 Cronartium jasclepiadewm on varied hosts... 53 jacksoniwe produeing witches’ brooms . 5 Crossbreeding wheats for rust- resistance 74 Crown or coronate rusts | 56 Cucumber diseases and copper salts 63 Cycle of development, in heteroe- cious species 3 58 in rusts... 2, 10 Cyperaceae, number of native rusts on Bc oes 45 Dactylis glomerata F eae 53 Daisy rust (Puccinia distincta) 10 introduced on seed... 209 Danthonia aecidium 18, 57 Darluca filum, a common parasite 22 mistaken forspermogonia 22, 158, oe Development of fungi ... af Dew necessary for infection 10 Diorchidium ... ie 83 doubtful genus * : 82 Distribution of Australian species 50 Distribution of spores... ae 7 Doubtful species - PR PRUANY| Drainage, effect on rust aa 71 Dry atmosphere and Late ger- mination “2 10 Karly maturing wheat escaping rust 74 Kehinulate uredospores... 19 Effect of rust on straw and grain 64 Elymus condensatus, importation of rust on seed ... aoe 43 Endcchrome 17 Endophyllum, teleutospores 2: Endospore, in aecidiospores 16 in teleutospores ... ecg 23 Enzymes in leaf cells... ae 54 Epispore of teleutospore 4 23 Epiteospores .., ste one 20 Erysiphaceae, specialisation of parasitism A 54 Erysiphe graminis, biologic forms 54 Bucalyptus globulus, supposed rust 49 General Index. PAGE. Euphorbia, aecidium of Pea rust 55 dentata «ws rae 70 rust (Uromyces euphorbiae) . - 70 Hupuccina ... ea a 1l Excluded species oon ave Fallowing, effect on rust one 72 Fertilisation, in aecidium 17, 75 in Uredineae 14, 75 Fir trees and rust ae 58 Flax rust (Melampsora lini) first record in Australia Formalin treatment of seed wheat 73 Frangula_alnus vee 53 Fungi, origin and development . 40 Fusion of nuclei ; , 75 Gall formation... 5 Gall fungi, on wattles (Acacias) .. ae 6 Genera, Australian, and number of species ... ae iy 50 General parasites ae dni 53 Germinating power, duration, in aecidiospores... aes 16 in teleutospores.... ish 8 in uredospores 8, 21 Germinating spores, methods for aecidiospores and _ uredo- spores ... wee ch 7 teleutospores : 66 Germination, of aecidiospores of Puccinia tasmanica es 16 of amphispores nF P 25 of teleutospores, factors in- fluencing 8 of Puccinia g graminis 8, 24, 66 of P. malvacearum ... 24, of Phragmidium rubi abnor- MOL. can va 35 of uredospores, of Puceiies bromina ‘ Lis udy iO of P. chr ysanthemi af 21 of P. dispersa ... Px 3 of P. graminis ... a7 21 of P. rubigovera... ae 8 of P triticina ... sits 21 Germ-pores, demonstrating me 12 in aecidiospores... inlay 2 in teleutospores_ ... 0 of Puccinia podolepidis ... 35 in uredospores +s a we solitary in Puccinia mono- pora ... rE des 19 Glycerine, and water... eo 12 jelly a 12 Golden rust (Puc cinia glumarum) 73 Golden wattle galls... ‘ 6 Gradations of specific variation ... 79 Gramineae, native rusts on os 45 Grass aecidium ae ewe 38 sy Grasses, and heteroecious rusts ... 57 and wheat rust... mr 69 Groundsel rust (Puccinia tas- manica) aa .. 16, 49 tymnoconia, characters... 83 Gymnosporangium, aecidiospores colored membrane re 6 galls - 6 insects conveying sporidiola 28 sculpturing of peridial cells ... 17 General Index. PAGE. Gymnosporangium clavariaeforme, direct infection by teleuto- spores ... cue a 35 confusum, promycelial cells separating ace ses 35 teleutospores, thickness of cell wall : 35 Hapalophragmium : 83 Hard tissues, softening... 12 Harvesting methods and rust 69 Haustoria 3 Hawthorn 28 Helianthus annuus, aecidia 18 Hemibasidii 40 Hemileia Ac 83 Hemipuccinia... at we 11 Heteroecious species... na 53 indigenous 45 regular development 57 Heteroecism oe 55 beneficial . 58 causing increased vigor 58 discovery .. 5 55 origin 55 when possible 55 Mreracium, Puccinia 80 Hollyhock rust (Puccinia malvace- arum) 8 wate 11 wide distribution ... 43 Holobasidii 40 Honeydew of spermogonia 13 Host and parasite, relation 60 Host-plants, imported, and new rusts 3 42 indigenous, and rusts 45 starved 60 Hot-water treatment of mead 73 Hypertrophy of nettle 6 Hyphae ser Hf 3 Immunity acquired 60 and predisposition .. Bs 60 attempts to secure . a62) 75 due to physiological peculiari- ties - 61 factors influencing ... xa 60 Importation of rusts as 42 on cuttings . ae so 43 on seed ... .. 43, 44 on straw ... 43 Incubation period er u) Indigenous species, tableof ... 46 and hosts .. Es 45 heteroecious 45 Infection, aided by i injury xf 61 and age of parts attacked ... 9, 60 by aecidiospores 9 by internal germ of disease .. 4 by sporidiola 9 germ tubes entering stomata 10 by teleutospores “ 35 by uredospores 9 germ tubes piercing epider- mal cells ; ant 10 dew necessary for ... 10 experiments, with parberry it in Australia 66 with foreign host plants | 4 factors influencing . 9 345 PAGE, Injuries, influence on infection 61 Inoculation, protective... e 62 Insects attracted, by colour of spores ... sad “i 38 by honeydew aes 13 by scent of spermogonia ... 15 conveying sporidiola : 28 eating spores : b-+ 7 Intermediate hosts of wheat rust 70 Internal developmental tendencies 53 Introduced species 42 how introduced 43 on native hosts... «.» 42, 49 Investigation of spores... a 11 Irrigation and wheat rust 71 Kangaroo thorn, gali fungus... 6 Knot-weed rust (Uromyces polygoni) 43 Lactic acid showing up germ ae = 12 Ledum palustre 5 56 Leguminosae, native rusts on 45 Leptopuccinia . A 11 one species with warted epipspore 23 Lettuce, attempt to confer immu- nity from disease “te 63 Liability a disease i : 60 influenced or not by structural characters sic Soc 61 Lichen-furgi ... Ane ae 37 Life-cycles of rusts “o¢ soe yO heteroecious aes ; 58 Life-history of rusts... aa i Liliaceae, native rusts on Adc 45 Linum marginale 43 usitatissimum : 43 rust-resisting variety 60 Lolium perenne, crown rust 53 with introduced rust 42 Mahonia in Kew gardens, rust free 68 Maize rust (Puccinia maydis) ... 42 Mallow rust (Puccinia malvacearum) 438 Manures and wheat rust 12 Marigold rust (Puccinia calendulae) 10, 42 Measuring spores by photography 12 Melampsora, eon of teleu- tospore 5 34 Melampsora eucalypti, “merely ¢ a name : BSc 49 hypericorum sor 22 lini 22, 49 introduced 44 paraphyses 22 Melampsoraceae , 82 Mesospores, in Puccinia 25, 26 in Uromycladium 25 Micropuccinia... Si Sa ll Mint, native, rust (Puccinia menthae) ; 42 Mounting spores 5a “a 12 Mycelium, development of vee 3 in seed of annuals ... Pr h, TAY investigation 3 localized, causing hypertrophy 6 perennial causing galls 5 no evidence in wheat grain 70 of Puccinia arrhenatheri ... 58 of Uromyces euphorbiae 70 General Index. 346 PAGE. Mycoplasm theory 4,74 bearing on rust in wheat 70 Native celery .. afr ae 42 flax ace ag ... 42, 44 mint die se 42 rusts, and native hosts 45 on imported hosts i 49 Nettle rust (Aecidium urticae) ... 6 Nuclear cycle... “- aa 14 Nuclei, fusion of i wars) Oat, wild, and wheat rust 69 Obligate parasites 52 Ochropsora ane 32 Odour of spermogonia ... 13 Omission of spore-forms 10 Origin of heteroecism 55 of parasitism §2 of spore-forms ae 31 Paraphyses, function ... os 29 in aecidia aed Pr Shy) in spermogonia... peraliaswee in teleutosori a 22, 24, 75 in uredosori ; ae 22 Australian species “with 22 Parasitism, origin ee 52 specialisation se 52 Pea rust (Uromyces pisi) 55 Peach or prune rust (Puecinia pruni) , 44 Pedicel of teleutospore .. He ame 23 Peltandra virginica is des 61 Perennial mycelium cee 5 Peridermium ..- ee eae lly/ Peridial cells ... oes 17 Peridium, = Pseudoperidium 16 often wanting eae 17 varied forms : out 7 Phalaris, Puccinia aa Sas 55 Photography in measuring spores 12 Phragmidiun barnardt, germ pores 24 paraphyses Ase ee 22 longissumum awe . 4 potentillac... ee 44 rubi, teleutospore ger mination 35 subcorticium 5, 36 paraphyses, in aecidi a 22 in uredosori Be 22 perennial mycelium a 5 Phragmites communis, Puccinia ... 29, 42 Phragmopyxis ace 84 Phycomycetes «.. 40 Phytopthora infestans, and copper salts ... ae 62 Picea excelsa 56 morinda 33 Ploughing, influence on wheat rust 71 Plum or prune rust (Puccinia pruni) ... sie hen 44 Poa annua 22 pratensis ... ae 22 Podisoma tex eee 28 Polygonum aviculare .. 43 Potash, caustic, for softening tissues ... Aas 0 12 Predisposition... pct 60 Primordia ; x ee it Promycelial spor es (see Spori- diola) Promycelium eee bat abnormal .. ee Ane cells of, separating ee elongated .. in various genera ied septa i“ Protective inoculation . Protobasidii ... ees Protomycelium ae Pseudoparenchyma Pseudoperidial cells (see Peridialce cells) Pseudoperidium (see Peridium) Puccinia, introduced species 42 variation in teleutospores 39 Puccinia agropyri, heteroecious ... 45 agropyrina ae 53 agrostidis . 45 anthoxanthi ; af 42 arenariae, introduced Seo: ge bee sporidiola germ-tubes enter- ing by stomata 10 arrhenathert, perennial myce- lium 58 asparagi, influence ‘of wind .. 7 water relation 9 beckmanniae. imported = 42 bromina contrasted with P. triticina.. 80 paraphyses i in teleutosori .. "24, 75 uredospore, duration of germinating power ... 8 germination and infection 3, 8 calendulae, marigold rust 10 Australian species a 49 short cycle AA ees 10 caricis, heteroecious et 45 COSULID aie ae tne 25 chrysanthemi, germination of uredospores ... As 21 introduced . rer 42 two-celled uredospores ... 19 cichorii, introduced eae 42 CINCTATUME... oor “oy 49 coronata ... a 53 cyani, intr oduced . ace) oe dianthi, sporidiola germ- -tubes entering stomata Sa 10 diehondrae, variation in teleutospores 39 dispersa, biologic forms .. 79 subdivision : one 53 distincta, daisy rust, Aus- tralian species ta 49 introduced on seed 209 short cycle Rr 10 festucae, introduced | ed 42 glumarum, mycoplasm theory + pense ie with aecidium on grass wee 18 graminis, biologic forms 79 carried over from year to year. a & in ‘Australia «as 215 G8 collective species ae 79 cycle of development... 58 forms on special hosts . 53 het eroecism increasin; g vigor ves tue General Index. PAGE, Puccinia graminis, ute hce on straw 43 injurious rust in n Australia 64 no aecidia in Australia ... 58 on grasses, wheat, &c. ... 70 repeated formation of uredospores 19 reproduced by uredo- spores in Australia 19 specialisation of forms ... 53 teleutospores,from Australia not germinating in Eng- land, and wee versd ... 67 germinating power 8 germination, exposure to cold not necessary ... 67 in Australia... coe 24. 67 in water... 36 time for 8 variation ac 39 uredospores, germinating power eee a 8 on old straw 69 germination ... 21 persist through winter . 8 graminis and barberry rust, connexion first discovered 55 in Australia bas .. 58, 66 in Kew Gardens ... 56 68 helianthi, germination of teleutospore .. 9 heterospora, one - -celled teleuto- spores most common 26 transition form 83 hieracti, spermogonia with uredo... sad “ce 13 subdivision of : 80 impatientis, introduced 43 liliacearum, spermogonia with . teleuto 13, 37 lolii, introduced 2 paraphyses in uredosori 22 magnusiana, heteroecious 45 paraphyses, in teleutosori and uredosori 22 malvacearum, causing ‘‘ shot- hole” 6 germination of teleutospores 24, 27 importation and were istribution A 43 suppression of spermogonia 14 maydis, introduced... ss 42 menthae, introduced 42 obtegens, peormncasas with uredo.. . 37 perplexans, on native host ... 49 paraphyses in uredosori 29 plagianthi, epispore 23 poarum, introduced Ae 42 paraphyses in uredosori ... 22, 29 uredo withstanding cold ... 22 podolepidis, two germ pores in upper cell of teleutospores 35 prainiana, abnormal teleuto- spore germination 36 prenanthis, introduced 42 peridium often wanting.... 17 347 PAGE. Puccinia pruni, causing ‘‘shot-hole” 6 first record in Australia ... Ay producing uredospores within fruits ... ad 19 supposed spermogonia 22 purpurea, introduced 42 rubigovera Sabet 28 of uredospores 8 paraphyses in teleutosori .. 24 subdivision ; 79 senecionis, repetition of aecidia 18 simplex, aecidia unknown ... 58 introduced fans aes 42 mesospores = ao 26 suaveolens, scent of sper- mogonia sie en (ures 5 is od ; ¥ hh wh 4 ; ae | in Pye nore eda EAS. a! ‘ ; , rf p iy W ° am Sag peek ey . 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