248 SUMMARY OF CURRENT RESEARCHES RELATING TO 



reach either the apex of the fertilizing ti;be or a short lateral pro- 

 tuberance ; the whole of the protoplasm contained in the apex of the 

 tube or in this protuberance then forces its way through the wall, 

 without any actual orifice being perceptible in it. In the union of 

 these with the j^rotoplasm of the oosphere he believes the act of 

 fecundation to consist. That these bodies are not parasites is shown 

 by the fact that they exhibit no trace of further development after 

 reaching the oosjihere ; that they are found in no other part of the 

 AcJilya ; and that the time of their appearance always coincides with 

 that of the maturity of the oosphere. When formed in tubes which 

 do not come into contact with an oogonium, they always perish without 

 exhibiting any indication of independent life. 



A. de Bary in reply,* admits the correctness of Pringsheim's 

 statement with regard to the entrance of these bodies into the 

 oogonium, which, indeed, he had himself previously described. But 

 he does not consider that there is at present any direct evidence that 

 they have any fertilizing function. Nor does this in any way explain 

 the phenomenon of parthenogenesis in Achlya, where fertilization 

 takes place without the presence of antheridia. De Bary supple- 

 ments his paper with diagnoses of the seven known species of 

 Sajprolegnia. 



W. Zopf contends f that the alleged " spermamoebse " of Prings- 

 heim are nothing but parasites, the occurrence of which in the 

 described situations in Achlya and Saprolegnia has long been 

 known. 



Morphology and Development of the Perithecium of Meliola.J 

 — H. Marshall Ward gives an abstract of his investigations of this 

 epiphytic fungus. The much branched mycelium consists of jointed 

 cylindrical hyphte, with hardened brown or black cell- walls, and 

 finely granular protoplasmic contents ; these are closely attached to 

 the epidermis of tropical plants by rudimentary haustoria, which are 

 closely adherent to the cuticle, but do not pierce the cells of their 

 host. 



Attached to and developed from the mycelium are setse, which 

 appear to have no special function, and are, at any rate, not tubes for 

 the passage of the spores. Other aj^pendages develope new mycelia 

 by budding, and others give rise to the perithecia, which are more or 

 less globular cases containing asci in their interior. Especial atten- 

 tion has been directed to these organs, and the " core " or contained 

 thin-walled cells is stated to be an ascogonium. The asci themselves 

 are delicate clavate sacs, containing two to eight spores ; each spore 

 developes a rudimentary haustorium, and gives rise to a mycelium. 

 The Meliolas appear to form a group, allied to the Erysipheae, &c., 

 but in which the sexual process is still more suppressed. The injury 

 caused by these fungi appears to be due to their depriving the leaves 

 of light and air, and blocking up the stomata. 



* Bot. Ztg., xli. (1883) pp. 38-46, 54-60. 



t Bot. Centralbl., xii. (1882) pp. 356-7. 



i Pioc. Roy. Soc, xxxiv. (1882-3) pp. 888-90. 



