with them; then, by simply brushing the water on the leaves, you may be pretty sure of successfully infecting the plant. Replace the bell-glass, and give it another douching outside with the watering-can. If sufficient material has been prepared, each alternate barberry may be infected in the same manner. The bell glass need not be kept over the infected plants more than two or three days. If the weather be very bright, the bell-glasses should be shaded by putting a piece of matting or carpet over them to prevent the foliage being scorched by the sun. In the course of eight or ten days the yellow spots on which the spermogonia are produced will appear, and in two or three weeks the perfect æcidiospores will be developed. It will then be seen that only those barberries to which the spores were applied have the acidiospores on them, while the alternate plants remain free. If an attempt be made to infect a plant in the day-time, when the sun's rays are full upon it, it will be found that the water all runs off the leaves; but by operating in the evening in the manner directed, the leaves are bedewed with a thin layer of moisture, and no difficulty will be found in applying the spore-charged water. Should it be desired to perform the converse culturethe infection of wheat plants with the barberry æcidiospores -greater care is necessary to prevent the control plants from becoming infected, because the acidiospores will not diffuse themselves in water, and are very readily carried away by currents of air. The simplest way is to plant some wheat in two flower-pots, and at once to place the pots on two plates of water and cover each with a bell-glass. As soon as the young wheat plants have made a green leaf, those in one of the flower-pots may be infected, using the same precautions as are given above. The acidiospores may be collected by brushing them into a watch-glass of water with a dry camel-hair pencil, taking care to use only those which will readily brush off. The contents of the watchglass may then be applied to the wheat plants. By this method the accidental infection of the control plants is avoided, because the bell-glass is never removed from them. Personally, I have found infection with promycelial spores more certain than with the acidiospores, because we can see that they are actually germinating at the time they are used, while with the acidiospores this cannot be done so certainly; moreover, the acidiospores being generally brought from a distance, they are apt to lose this germinative power, unless used immediately, from becoming too dry on the one hand, or on the other, if kept in too moist an atmosphere during their transit, from many of them having already germinated before they are employed. It is only by attention to these minute details that we can ensure uniform success. The Gymnosporangia are very easy to cultivate. A few seedling hawthorns can be obtained anywhere, and it is necessary only to soak the Gymnosporangium clavariæforme for twelve hours, when the golden promycelial spores will be visible to the naked eye. In producing R. cancellata on pear, it is necessary to infect two-year old plants, because if seedlings be infected the spermogonia alone will be produced, because seedling pears lose their foliage before the Roestelia has had time to develop; with these plants it is essential to success that they should be thoroughly established before they are made the subject of experiment. In working out the life-history of the allied species duplicated cultures are very valuable. Suppose we wish to produce the acidia of P. magnusiana and P. phragmitis. Having provided the proper material and a number of growing plants of Rumex obtusifoliius and Ranunculus repens, germinate a quantity of the P. magnusiana in a watch-glass, and then put half on a Rumex and the other half on a Ranunculus; in a week or ten days we shall find the Ranunculus affected and the Rumex free. Care, of course, must be taken that there is no mixture of teleutospores in the watch-glass. In like manner the P. phrag mitis may, on a subsequent occasion, be applied to the other two plants, when we shall find the Rumex become affected and the Ranunculus will remain free. The main points to be attended to in order to ensure success in performing these cultures are, first and foremost, to have ocular demonstration that your infecting material is actually germinating at the time you use it; and, secondly, to infect the young growing foliage of established plants. DESCRIPTIONS OF THE BRITISH UREDINEÆ. UREDINEÆ. Tulasne. MYCELIUM parasitic in living plants. Spores formed from the ends of erect, crowded hypha, usually of more than one kind. Teleutospores germinating by a short promycelium. Teleutospores separate, unicellular, pedicellate, produced in flat sori (spore-beds), apex perforated by a single germ-pore. Having spermogonia, æcidiospores, uredospores, and teleutospores, the latter germinating only after a period of rest. A. AUTEUUROMYCES. Having all spore-forms on the same host-plant. Uromyces fabæ. (Pers.) Ecidiospores-Pseudoperidia generally crowded upon whitish spots, which are more or less circular, short, slightly prominent, flat, with torn white edges. Spores subglobose, orange-yellow, finely echinulate, 15-25μ in diameter. Uredospores-Sori chestnut-brown, roundish, amphigenous, scattered, often confluent, soon naked. Spores subglobose or ovate, with three germ-pores, shortly echinulate, yellowish brown, 20-30 × 17-20μ. Teleutospores-Sori rounded on the leaves, more abundant and elongate on the stems, persistent, black. Spores variable in form, ovate or broadly clavate, dark brown, smooth, apex much thickened (8-10p), rounded or conical with one in fundibuliform germ-pore, 25-40 X 20-25μ. Pedicels long, persistent, pale brown. Synonyms. Uromyces orobi, Pers. Winter in Rabh., "Krypt. Flor.," 2nd edit., vol. i. p. 158, in part. Uromyces fabæ. Cooke, "Grevillea," vol. vii. p. 135. Uromyces appendiculata, Lév. "Micro. Fungi," 4th edit., p. 212. Cooke, "Hdbk.," p. 518; Uredo fabe, Pers. Romer, "New Mag.," vol. i. p. 92. Grev., "Scot. Crypt. Flor.," t. 95; "Flor. Edin.," p. 436, in part. Uredo fusca. Purton, "Midl. Flor.," vols. ii. and iii., No. 1130. p. 225. Cooke, "Micro. Fungi," 4th edit., Puccinia globosa. Grev., "Flor. Edin.," p. 368; "Scot. Crypt. Flor.," t. 29. Puccinia faba, Link. Berk., "Eng. Flor.," p. 434. Cooke, "Hdbk.," p. 508; "Micro. Fungi," 4th edit., p. 211. Exsiccati. Cooke, i. 71; ii. 52. Vize, "Micro. Fungi," 44; "Micro. Fungi Brit.," 63, 223. On Faba vulgaris, Vicia cracca, sepium, sativa, Lathyrus pratensis, Pisum sativum. Æcidiospores, April and May; uredospores, May to July; teleutospores, July to November, and lasting through the winter. on the dead stems. BIOLOGY.-There are several species of Uromyces parasitical upon the Leguminosæ. By most botanists the above is considered identical with U. ervi. As early in the year as February 8 (1884), I produced the Æcidium upon a bean plant (V. faba) from teleutospores on bean straw which had been grown for agricultural purposes. The latent period between placing the teleutospores on the host-plant and the appearance of the spermogonia was twenty-three days. The culture was repeated on March 20 in two experiments, both of which were successful, the spermogonia in each case showing on April 16. In 1886, four cultures were made with U. ervi by placing the germi |