83 



ON SOME NEW AND EARE DESMIBIEM. No. III. 



By W. Joshua, F.L.S.* 



(Tab. 254.) 



The following new and little-known species have recently 

 occurred in collections received from foreign correspondents. The 

 plate and description of No. 1 I take from the valuable published 

 series of Algte of Messrs. Wittrock and Nordstedt. This small 

 FAMstrwii was collected from Sphagna;, by J. Hart, Esq., in the 

 Blue Mountains, Jamaica. 



My first acquaintance with Canadian DesmidiecB, from a collection 

 forwarded in the past summer by the kindness of Mr. A. H. McKay, 

 has brought to light a very distinct and beautiful new form of an 

 old friend, Kuastnim remicosum Ehrenb. ; also Closterium Braunii 

 Reinsch, Staurastrum polytrichum Perty f. major, S. lunatum Ralfs, 

 Cosmarium TurpiniBveh, fi. LundeUii, Staurastrum orbicidare (Ehrb.) 

 Ralfs. f. 7» mo?- Nordst., Cosmarium Qnasillus Lund., C. Botrytisft. sub- 

 tumidum Witivv . , Hyalotheca dissiliens f. tridentula'^oi'dst.,Micrasterias 

 americana Ralfs. (cytioderm spinulose), Staurastrum polymorplium 

 (four-rayed), C. crenatum Ralfs. f. hicrenatum Nordst., C. Cordanum 

 Breb. = Colpopelta viridis Corda, Xanthidium antilopeum new var- 

 canadense (a stout form with side spines in centre of semi-cell). 



The new species from Rangoon are from a large collection, at 

 present under examination, received from Dr. Romanis. 



Penium spinospernuDii (Journ. Bot. 1883, 293) was collected by 

 the Rev. H. W. Lett of Ardmore, Lurgan ; these zygospores much 

 resemble those of C. glohosmn Bulnh. No. 11, with its singular 

 spore, is a somewhat rare species, new to this country. The 

 drawings are made from specimens taken by me in the neighbour- 

 hood of Cirencester. I may here mention the valuable addition to 

 our Desmid literature, entitled ' Desmids of the United States,' by 

 the Rev. F. Wolle, which has recently appeared in America, and 

 would be a decided boon to any student of this class. It is replete 

 with a large amount of original information and excellent coloured 

 plates. Among the eleven hundred species figured, a vast number 

 will be recognised as having a home in this country. 



1. Euastrum incavatum Josh, et Nordst., nov. spec; 

 Wittrock & Nordstedt, Alg» exsiccatfe 657. — E minimum incisura 

 mediana lineari angusta [intra ostium x^auUulo dilatata ; semi- 

 cellulse pyramidales e basi dilatata sensim in lobum polarem 

 attenuatfe, lateribus Ifeviter latissimae retusis, angulis inferioribus 

 oblique truncatis, lobo polari superue tantum laevissime dilatato, 

 margine superiore late rotundato medio retuso] incavato, angulis 

 subacutis ; a latere visae ovatae ; a verticte conspect® ellipticaa ; 

 anguli superiores et inferiores oblique e vertice visi obtusi utrinque 

 parvo ornati ; membrana glabra. Long. 40-43 p ; lat. 24 fx, lat. 

 apic. 12 /x ; crass. 14-16 /x. Habitu Micrasterias Integra Nordst., 

 Euastrum ansatmn Ehrb. Exi. cmieatum Jenn. lianc speciei proxima 



* See Journ. Bot. 1882, 300 ; 1883, 290. 



Journal of Botany. — Vol. 23. [February, 1885.] d 



