1897.] Proceedings of Irish Societies* 327 



figure). Dr. Spruce writes : " of all South American Lejeunect, gathered 

 by myself or known to me from other regions, L. Holtii sQ^ms to stand 

 nearest a small group of which I have described three species under the 

 name Potamolejewiea. These all grow in North Brazil, almost on the 

 actual equator." 



Rev. H. W. Lett sent for exhibition specimens of Fossombronia cristata^ 

 This hepatic, which does not appear to have been recorded from Ireland, 

 was found by him in October, 1890, growing abundantly on the shore of 

 Lough Bricland, Co. Down, and was mentioned in a paper he read shortly 

 afterwards before the Belfast Naturalists' Field Club, which, however, 

 was not published in their Proceedings. The habitat was a bed or flat 

 bank of a whitish stiff clay, which is usually covered by water, but had 

 that season been dry for several months. The tufts were from half an 

 inch to two inches in diameter, in the form of little rosettes of a vivid 

 green colour. The individual plants were densely tufted and taller than 

 F, pxisilla, which abounds in a wet autumn in all the clover-fields in the 

 neighbourhood. The spores are covered with ridges or crests. 



Mr. AivivAN Swan sent for exhibition Olpidiopsis Saprolegnicv (Cornu), one 

 of the Chytridiacae group of aquatic Phj-comycetes, cultivated from 

 Spirogyra collected at the Bofinna lake, in the mountains near Bantr}'. 

 This plant is of special interest since its life-history was worked out by 

 Cornu. The exhibitor is not aware of it having been previously recorded 

 in Ireland. It lives as a parasite which develops in the filaments of the 

 Saprolegniaceae, living on the protoplasm of its host. The filaments in 

 which it grows assumes a short clavate shape, and the zoosporangia of 

 the parasite are produced in their enlarged extremities. These zoospo- 

 rangia are generally oval, but vary somewhat in shape and greatly in 

 size, while their number — as was shown in photographs — may mount to 

 over a dozen, or, as is more general, be restricted to a single one of 

 greater dimensions. The zoospores which are contained, to the number 

 of several hundreds, in each sporangium, are active swarmers, with a single 

 cilium, and unusually small (^^ of a millemfetre— say ^J^ of an inch). 

 Their movement begins before they escape into the surrounding liquid, 

 an outgrowing tube from the zoosporangium serving for their liberation. 

 They are said to have the power of penetrating the walls of the plants 

 in which they live as parasites. Some of these zoospores are, however, 

 liberated into the empty filament of their host, and, with their j" active 

 movement, can from there easily reach its mycelia, whence they may be 

 able to penetrate to other growing filaments. In the photographs were 

 to be seen zoosporangia in several stages of maturity. Many with their 

 zoospores ready to escape, others empty, after the liberation of the zoo- 

 spores ; the outgrowing tube could also be seen through which they escape 

 from the sporangium. One example of the second mode of reproduc- 

 tion—by means of resting spores which have short outgrowing spines- 

 was also shown. 



