INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC, 599 



cells of Pinics amerkana, as many as twenty or thirty of the para- 

 sites being found in a single grain. The escape of zoospores 

 from these may occasionally be observed. Chytrklia were also ob- 

 served in the pollen-grains of Typha latifolia, Lilium lancifolium, and 

 Cannabis sativa. Chjtrklium luxurians, also endophytic in the pollen 

 of Pinus sylvestris, is distinguished by the fact that it never leaves the 

 pollen-grain, but, when mature, emits a tube which projects outside 

 the pollen-grain, through which the zoospores are ejected. The de- 

 velopment of these truly endophytic fungi is often obscured by the 

 growth of other fungi among the pollen-grains, the germs of which 

 have been floating in the air, &c. ; especially of Apisporium pinophilum 

 Fuckel, which first appears as a torula, and then develops dark 

 brown, club-shaped perithecia. 



Rate of Germination of Fungus-spores and Growth of My- 

 celium.* — Dr. G. Winter has made a series of experiments on this 

 subject, extending over a considerable number of species belonging 

 to several diiferent orders of fungi. 



The germination of the spores he found to be dependent on 

 a variety of circumstances, such as sufficient access of oxygon and 

 a sufficient supply of moisture, some germinating in moist air, 

 others only when swimming on or actually submerged in water. 

 In some species the development of the germinating filaments takes 

 place at the expense of the food-materials stored up in the spore ; 

 others require an external supjily. For the germination of most 

 fungus-spores a temperature of from 12 to 20^ C. is necessary. Of a 

 large number of fungus-spores which were subjected to experiment, 

 the most rapid germination was exhibited by Nectria cinnabarina, 

 viz. in 2^ hours ; the least rapid by Actrostalagmus cinnabariniis, 

 viz. in 65i hours. The slowest development of the germinating 

 filament was manifested hj Mucor Mucedo, viz. at the rate of 2' 5 

 mmm. (micro-millimetres) per minute in a nutritive fluid, | mmm. 

 per minute in water ; the most rapid by Pilobolus crystallinus, viz. 

 at the rate of 36 mmm. per minute. 



New parasitic Phycomycete.f — In the ' Sitzungsberichte des hot. 

 Vereins der Prov. Brandenburg' W. Zopf describes a new fungus 

 allied to the Saprolegniete, which is parasitic on Spirogyra and other 

 filamentous Conjugatte, and which he names Lagenidmm RabenJiorstii. 

 The biciliated swarmspores attach themselves to a cell of the host, 

 invest themselves with a cell-wall, perforate the wall of the infected 

 cell by means of a filament, and develop into a unicellular mycelium. 

 The hyplias afterwards become septated, and each cell is a zoosporan- 

 gium, containing from two to thirteen zoospores. The sexual plants 

 are produced from zoospores which penetrate a cell of the host in 

 pairs, one giving rise to a male, the other to a female plant. The 

 male plant becomes divided into a number of cells, all but one of 

 which produce zoospoi*es, the other becoming an antheridium ; it 

 does not give birth to antherozoids, but pierces the female cell, into 



* ' Hedwigia,' xviii. (1879) p. 49. 



t Sec ' Bot. Zeit.,' xxxvii. (1879) p. 351. 



