23S 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
its pedicel perforating the wall of the cell. They ultimately attack and 
deform the nucleus of the host-cell. 
Pseudo-fecundation in the Uredineae.* * * § — M. Sappin-Trouffy describes 
the three stages of this process in the case of Gymnosporangium Sabinde , 
viz. the formation of the teleutospore, the fusion of the nuclei, and the 
germination of the spore. The teleutospore is formed on a hymenial 
layer differing perceptibly from the subjacent hymenial stroma, and each 
cell of this layer may produce two or three spores. All the cells of the 
hymene are bi-nucleated ; the nuclei of those which are to produce 
teleutospores are especially large, and contain nucleoles ; the two nuclei 
of the spore may eventually be separated by a septum or not. The 
process of pseudo-fecundation consists in the fusion of these nuclei. 
The teleutospore has four pores, whether it be unicellular or bicellular. 
The promycele resulting from the germination of the teleutospore con- 
sists of four cells, each with a single nucleus. Each of these cells gives 
birth to a slender tube, which swells up at the apex to form a conid. 
Fertilization of the Pucciniese.t — M. P. Vuillemin describes the 
process of the formation of the secidiospores in Peridermiurn Pini (the 
cecidio-form of Coleosporium Senecionis ) termed by Dangeard pseudo- 
fecundation, which he regards as a true process of fertilization, the 
aecidiospore being the generator of a new plant. The two nuclei of the 
fertile cell which conjugate are gametes identical in their origin and in 
their morphological value. The process may be compared to the fusion, 
in the embryo-sac of Angiosperms, of the two nuclei, the result of whose 
union is the formation of the thallus known as the endosperm. The 
previous separation of an abortive cell is analogous physiologically to 
the throwing off of a polar cell. 
Puccinias Parasitic oil Compositae.t — Herr P. Magnus describes in 
detail the various forms of Puccinia belonging to the type P. Hieracii , 
parasitic on different species of Compositae. They belong to four 
sections, viz. : — (1) Auteupuccinia ; these develope spermogones, aecidia, 
stylospores, and teleutospores on the host ; (2) Brachy puccinia ; develope 
spermogones, stylospores and teleutospores in the first generation ; from 
the stylospores small masses are formed, which again develope stylo- 
spores and teleutospores ; (3) Pucciniopsis ; only spermogones and 
aecidia are produced in the first generation, only teleutospores in the 
second ; (4) Micropuccinia ; only teleutospores are produced, and only 
one generation in a year ; the teleutospores fall off readily, and germinate 
in the next spring. Forms of the second and fourth types occur, 
especially at high altitudes, where the period of vegetation is short. 
Puccinia Paridis and interstitialis. — Dr. C. B. Plowright and 
Mr. W. Thomson § have established the genetic connection between the 
rare aecidium found on Paris quadrifolia and a Puccinia parasitic on 
Phalaris arundinacea. Four other species of Puccinia are already 
known to be parasitic on this grass, viz. P. sessilis, Phalaridis , Digra- 
phidis, and coronata. The aecidia of these species occur on four different 
* Le Botaniste (Dangeard), iii. (1893) pp. 205-8. Cf. this Journal, 1893, p. 666. 
f Comptes Rendus, cxvi. (1893) pp. 1464-7. 
X Ber. Deutsch. Bot. Gesell., xi. (1893) pp. 453-64 (1 pi.). 
§ Journ. Linn. Soc. (Bot.), xxx. (1893) pp. 43-4. 
