484 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Growths of Moulds in Oil.* — Henri Coupin noted that if any 

 organic body were dropped to the bottom of a flask of oil, Penicillium 

 glaucum was formed on it, and produced normal conidiophores and conidia, 

 and he contrasts this with the growth of the same fungus under water : 

 in the latter case the mould produces only mycelium. He made experi- 

 ments with a series of moulds, various Mucorini, as well as with Peni- 

 cillium, Cephalothecium roseum, and Botrytis cinerea. They all grew on 

 sterilized carrot immersed in oil, but the mycelium remained short, 

 and evidently was nourished by the carrot and not by the oil. In the 

 majority of cases the mycelium remained sterile. In the cases where 

 fructifications were formed, they were deformed (Sporodinia), or they 

 were less abundant than in the air (Penicillium and Gunning hamiella). 

 No resting-spores or sclerotia were formed in the oil. On the whole, 

 the vegetation of moulds under oil is more like the growth under water 

 than aerial growth. 



Uredinese.t — 0. Morgenthaler has investigated the conditions 

 affecting the formation of teleutospores, more especially in connection 

 with Uromyces Veratri-homogynes. He finds that it depends on the 

 condition of the host-plant whether teleutospores or uredospores will be 

 formed. As a rule, uredospores were formed after infecting young 

 leaves either with uredospores or a3cidiospores ; if older leaves were 

 infected with the same spore-material, teleutospores were developed. 

 Any disturbance of nourishment induces the formation of teleutospores. 

 In another paper} he gives the results of a long series of culture 

 experiments on the same subject, viz. the connexion between the forma- 

 tion of teleutospores and the condition of the host-plant ; he found that 

 a sickly state of the host, or advanced age and approaching withering, 

 tended to restrict uredo-formation and encourage teleutospores. 



Sexuality of Rust Fungi.§— L. Kurssanow has studied to throw 

 further light on a somewhat debated subject. Olive held that there 

 was fusion in the ajcidium between two fertile cells that differed in size : 

 that on conjugation there was either a large passage through which 

 the cell-contents passed, or that only the nucleus found its way into the 

 receptive cell. L. Kurssanow chose Puccinia peckiana, a similar form to 

 those examined by Olive and Christman. Spermogonia are formed 

 below the epidermis, and are followed on the under side of the leaves by 

 the caioma, a confused tissue of hyphaj, from which arise palisade-like 

 cells with large nuclei. These palisade-cells divide into an upper sterile 

 and an under fertile cell. The fertile cells conjugate in pairs by a large 

 opening in the cell-wall ; the sterile cells disappear. Kurssanow could 

 find no difference between the fertile cells ; all of them possessed the 

 upper sterile cell. He did not attach importance to the passage of a 

 nucleus from a vegetative cell to a neighbouring fertile cell ; he con- 

 sidered that to be a result of the artificial conditions. 



From each bi-nucleate fertile cell rises a row of secidiospores, but 



* Comptes Rendus, cl. (1910) pp. 1192-3. 



t Arch. Sci. Phys. Nat. Geneve, xxviii. (1909) pp. 489-99. See also Bot. 

 Centralbl., cxiii. (1910) p. 448. 



t Centralbl. Bakt., xxvii. (1910) pp. 73-92 (18 figs.). 



§ Zeitschr. Bot., ii. (1910) pp. 81-93 (1 pi.). See also Centralbl. Bakt., xxvi. 

 (1910) pp.,G91-2. 



