STAURASTRUM. 



215 



This variety differs from the type in the lower portion of the angles of 



m the slight inflation of the 



produced, and also 



differ considerably from that of the type. 



angles. 



■emieells being 



features cause the verti< 1 vitw to 



In the front view the api 



i v 



of 



are alight! 



retuse, and the sinus is also more open. We think Schmidle's fig. 17a (Ost-Afrika Desm 

 somewhat oblique. Schmidle has also recorded this Desmid from the vicinity of Lake Nyaaw, but 

 the figure he gives is of a form with shorter spines (vide Schmidle, Alg. aua Nva*a-8ee, 1 i, p. 



73, t. 2, f. 8). 



Schmidle also remarks that Si. 



W 



G 



1897, p. 177, t. 36, f. 



West (Welw. Afric Frrabw. A If 



should be placed as a from of St. *ubtrif una turn, but 



it from the latter species at the time of its publication. In St. tride\ 

 at each angle of the semicells are situated vertically oter one another 

 and stouter. Moreover, the vertical view is pentagonal with acute angle*. 



Nept 



on* 



we diatinguishtd 



the three tpii * 



id are 



* 



Ik rl- r 



In the same paper Schmidle describes a "forma hi Jem" of 



been recorded from Java 



Gutwinski. It 



tri/urcatum^ and this has aince 

 the "forma btdm*" in much 



more nearly akin to St. longlspinum (Bail.) Arch, than to - 

 vertical view and the presence of only two long spines at each 

 one over the other, lend strong support to this view. 



ifurcat 



which 



Tim form of the 



rtioally 



otad 



1 



Staurasteum disparatum sp. II. (PI. XVI, fig 



St. nied 



paullo 



g 



quam 



m( 



spinis), profunda const rictum. sinu 



valde 



perto et 



rectis vel 



brectis 



apice 



gulari; semicellulse late triang 



i retuso (subrecto), 



marginibus inferiorib 



evissim 



gal 



leviter b 



lobo 



infer 



l spina va 



da 



g 



ubdivergenti instructo, lobo gupcriori spinis binii mult 



«• 



minoribus 1 



dispositis instructo; a vertice vimb triang 



1 



evissime retusis (subrectis 



£ 



spinos 



lidos longos productis 



quemque spinis binis pa 



prope basin sp 



valida? : meml> 



Long, sine spinis 33/*; lat. sine spinis 27-29/*; cum sp 



..2-5-G 



lares, litcribus 

 intra angulum 



glabra. 

 u\ lat. isthrn. 



8'6 



I* 



Hob 



Mansang, near Hsip 



24193) 



Ceyl 



This species approaches St. Trttmanii var triqudrum W. & G. S. West (Freshw. Alg 

 1902 p 177 t 21, f. 22), but is easily distinguished by the large simple aculei it eacl 

 by the ' triangular semicells, and by the rectangular sinus. The three pairs of small spines at 

 the apex of each semicell are also situated much nearer the angles; they ere sborter thr- < - 

 of St. Freemann, much less divergent, and in the vertical view they do not project beyond th. 



those 



margin 



13,* 



St. 



acutang 



Staurastrum Man 



sp 



n. 



(PI xvi fig 



parvu m 

 o et £ 



* 



circiter tam 



perto 



g 



mgum quam 

 ad apicem : 



latum, 



profunda constrict um, 



sinu 



semi 



btrapezoidcae (vel late 



pyramidal), lateribus et apice leviter convexis, 



gul 



basal i bus et super i 



bus verruca emar 



lateralis 

 apicalem 



cuj usque 



> 



praeditis, cum 

 etiam verrucis 



verruca emar e 



ad med 



marginil 



ginatis duobus juxta et infra margmem 



a vertice vi^ae triangula 



ibus leviter convexis, 



gul 



in verm cam 



emar 



em 



m subiter produ 

 unuroquemque et 



serie verrucarum 



ginatarum 4 intra marginem 



pinis minutis geminatis prope 



gulum unumq 





utrobique. 



Long. 



Hab. 



26/* ; lat. 24'5/t ; 



lat istbm. 7'5/t. 



Mansang, near 



Hsipaw (No. 24193) 



Ann. Roy. Bot. Gard. Calcutta Vol. VI 



