222 SUMMARY OF CURRENT RESEARCHES RELATING TO 



spermatia, and that there is now only a reduced process of fertilisation, 

 which is mid-way between the normal process and that discovered in 

 the case of apogamy in ferns, where the acting male and female cells 

 are ordinary vegetative cells. He gives some notes on nuclear division 

 as observed by him in the Uredineae. A fuller account is promised at 

 an early date. 



Cultures with Rusts.* — H. Klebahn gives the results of his various 

 cultures, and notes the points of interest in connection with the infec- 

 tions. He found that Nemesia versicolor was extremely susceptible to 

 Cronartium asclqriadum, and he concludes that a fungus may suddenly 

 choose a new host. Specialisation may proceed from many hosts to 

 one (plurivore fungus), or from living on a single host (univore) the 

 rust may develop a capacity to infect several. He finds, also, that in 

 the course of several generations the power of infecting hosts other than 

 the one on which the fungus has been cultivated, gradually declines. 



Ag-aricinese on Trees.f — P. Hennings has gone carefully over the 

 species found in Germany on stumps, roots, stems and branches. He 

 notes those that are parasitic. The largest number is recorded on the 

 Alder. He does not give many that grow on Conifers, as trees of that 

 order were rare in the district examined. He found none on Ash trees. 

 Armillaria mellea causes much damage in the woodlands, and attacks a 

 large number of trees, Conifers as well as deciduous trees. 



Polyporaceae of North America.^ — "W. A. Murril continues his 

 studies of this great group, and deals in the present paper with the 

 genus Polyporus. He confines the name mostly to species of " small 

 dark-coloured plants attached to fallen branches and other decaying 

 wood on or near the ground." They are all furnished with a stipe 

 centrally or variously attached. There is the usual shifting of names 

 to establish priority. Polyporus brumaUs becomes P. polyporus Murril, 

 as it was described as Boletus Polyporus by Retz in 1760. The author 

 records twenty-three species of the genus as understood by him for 

 North America. 



Merulius lacrymans as a cause of Cancer.§ — A. Klug has given 

 much attention to this subject. He claims to have found in the secre- 

 tions from cancer a form of yeast-spores identical with some stages in 

 the development of dry-rot. He calls these cells " Meruliocyten." The 

 fungus would thus be a dangerous parasite to men and animals. 



Spore-formation in Naucoria nana.|| — L. Petri reviews the work 

 done on the basidiospore by Maire, Wager and other writers. He finds, 

 the two nuclei (the synkarion) present in the hyphae of the trama, as 

 described for other hymenomycetes ; they are of extremely minute 

 dimensions. Fusion takes place in the basidium in the spirem stage,. 



* Jahrb. Hamburg. Wiss. Anst., 1902, 3 Beiheft., 56 pp. Hamburg, 1903. See 

 also Bot. Zeit., lxi.(1903) pp. 322-4. 



t Hedwigia Beibl., xlii. (1903) pp. 233-40. 



t Bull. Torrey Bot. Club, xxxi. (1904) pp. 29-44. 



§ Freih. Johannisbad, Sebbstverlag, 139 pp. (42 figs, and 1 pi.). See also Ann. 

 Mjcol., i. (1903) pp. 4i;G-7. 



|| Nuovo Giorn. Bot. Ital. x. (1903) pp. 357-71 (1 pi.). 



