DUBLIN MICROSCOPICAL CLUB. 301 



resembles Tsuga Hookeriana at first sight, but is very different, 

 and most closely approaching the plant cultivated in Glasnevia 

 Botanic Garden, Dublin, as Picea Alcockiana, from Japan. It 

 has a single fibro-vascular bundle in the leaf and two resin-canals, 

 and, like Tsuga and Picea, the leaves are placed on a large cushion. 

 The upper side of the leaf is white with stomata, and the two 

 resin-canals, like those of P. Alcockiana, are situated close to the 

 under surface, and about midway between the fibro-vascular 

 bundle and the margin of the leaf. 



The hypoderm is largely developed, more than in P. Alcockiana, 

 and the leaf is more tetrapronal than in the Japanese neighbour. 

 An examination of the Vancouver's Island form shows that 

 Abies Williamsonii is probably a distinct species, closely related 

 to the Japanese one, and that all the specimens cultivated as A. 

 Williamsonii are to be referred to the section Tsuga. The rela- 

 tion of a species from Vancouver's Island to the Japanese one 

 is too interesting to be overlooked. 



On a minute species of Cosmarium with smooth dark hrown 

 zygospores. (See ' Club Minutes' of Nov., 1876) ; the same also 

 occurred in Italy. — Mr. Archer showed a preparation by Herr 

 Nordstedt of Lund of a desmidian form, with zygospore, marked 

 as Sphcerozosma excavatum, cum zygosp , and collected by that 

 observer in Italy. This was seemingly in every way. as regards 

 the zygospore and otherwise, both in form and tint, quite iden- 

 tical with that Mr. Archer had exhibited at last November Club- 

 meeting as a new species of Cosmarium, which he had proposed to 

 name Cosmarium minutissiinum. He had since then forwarded 

 conjugated Irish examples to Mr. Roy, who completely agreed 

 with him that the form belonged to Cosmarium, wanting, as it 

 did, all trace of the minute connecting processes or papillae apper- 

 taining to Spha^rozosma ; it was also (by comparison) consider- 

 ably more minute than the joints of Sph. excavatum, besides 

 being likewise of a diffisrent form. In Sph. excavatum the con- 

 struction forms a rounded sinus on each i-ide — in the form under 

 consideration a minute acute incision ; in the former the zygo- 

 spore is colourless, in the latter very dark brown. There are 

 some three or four of these excessively minute smooth forms of 

 Cosmarium extremely like one another and but slightly differing 

 in their dimensions (rather degree of minuteness!), but their dif- 

 ferences, slight as they are and difficult to successfully pourtray 

 on paper, are there, and seem constant, whilst not less so and 

 more striking are their different zygospores. Cosvi. minutissimum 

 (here so-called), is quite a distinct thing from any of these. 



Lejeunia patens, eocliihited. — Dr. Moore showed a pretty and 

 minute form of Lejeunia, L. patens, Lindl., which he had col- 

 lected at Cromaglown (Killarney), and considered it an exactly 

 similar form of that species to one collected by Dr. Spruce at a 

 great elevation on the Peruvian Andes and named L. patens, var. 

 cochleata. Like all the minute Hepaticse, this formed a very 

 pretty object viewed under a moderate power. 



