PLEUROT.ENIUM. 



195 



The specimens agreed exactly with those observed from Ceylon and from several parts of the 

 United States. Whether PL trochiscwn is identical with PI. testatum (Josh.) Lagerh. or not 

 appears to beji question which can only be decided by an examination of the original specimens 



tetsehtum: Judging from the experience we have already obtained of the 



of Joshua's l D 



inaccuracy of many of Joshua's figures and descriptions, 



probable. Both species 



are also very possibly synonymous with Bailey's < Docidium rerruco&um,' but again the published 

 accounts of this species are not sufficiently reliable to admit of a critical comparison. 



56. Pleurot^nium cristatum (Turn.) Borge, Trop. u. subtrop. Sussw. Chlor. 



1899, p. 15. 



Doeidium cristatum Turn. Freshw. Alg. E. India, 1893, p. 32, t. 4, f. 7. 



Forma marginibus semicellularum non undulatis; tuberculia 84-36 ad apioem 

 (18-19 visis). 



Long. 680-1130/*; lat. bas. semicell. 36-66/*; lat. ad mod. senncell. 29-5 <V ; 

 lat. ad apic. 33*5-59/*. (PI. xm, fig. 11). 



Hah. — Mansang near Hsipaw (No. 24193). 



This Pleurotcenium occurred abundantly and was very variable in size, the largeit specimeni 

 being double the size of the original Indian plants. The semicells in all cases had one slight basal 

 inflation, parallel or subparallel sides without any trace of undulations, and a very slight inflation 

 under the apex, which was slightly contracted immediately below the crown of tubercles. Th« 

 number of tubercles on the apex was 34, or sometimes 36, whereas Turner gives 30 as the number 

 on his Indian specimens. Turner also states "margine leviter undulatum," but his figure indicate! 

 almost parallel sides. The figure given by Borge (I.e. t. 1, f. 11) of a form from Cuba bas not 

 more than 18 or 20 tubercles at the apex of the semicell and in this character it differs consider, 

 ably from Loth the Indian and Burmese forms. 



Two other species described by Turner must be considered as forms of PI. rrhlatum. These 

 are 'Docidium orientate Turn.' and 'Docidium cylindricum Turn.' The former is dottitute of the 

 slight inflation below the crown of tubercles, and the number of tubercles is 36-44. The latter is 

 a shorter form with 38-40 apical tubercles. 



but 



The plants in question might be considered as follows: 



Pleurotcenium cristatum (Turn.) Borge. PI. magnum, cellulis diametro 17-19-plo 



fere rectum vel leviter curvatum ; semicellulse cylindrical, ad basin leviter inflate, lateribus 

 parallelis (vel levissime undulatis?), apice leviter inflate, tuberculis parvit 30-36 (visit 



16-19) ornato. 

 Forma orientalis (Turn.) nob. Apice semicellularum noa inflate sed paullo expanse, taberculit 



36-44 (visis 18-22) omato. 

 Forma cylmdrica (Turn.) nob. Cellulis diametro 10-plo longioribus, ad apices cum tuberculit 



38-40 (visis 20). 



57. Pleurot^nium Cuyabense Borge, Alg. erst. Regnell. Exped. ii. Desmid 



1903, p. 84, t. 2, f. 8. 

 Forma inornata. (PL xm, fig. 10). 

 Forma paullo major, apicibus semicellularum sine 



berculit 



i- 



Long. 600/*; lat. ad bas. semicell. 54/*; lat. ad apic. 81** 

 Hah— Kyauktaga, Pegu district (No. 22124). 





