113 



WELWITSCH'S AFRICAN FRESHWATER ALG^E. 



By W. West, F.L.S., and G. S. West, A.R.C.S. 



(Plates 365-369.) 

 (Continued from p. 89.) 



12. CosMARiuM Corda (1834). 



1. C. centrotaphridium, sp.n. (tab. 367, figs. 3-6). C. sub- 

 mediocre, paullo longius quam latins, profande constvictum, sinu 

 angusto-lineari ; semicellulte subtrapeziformes, angulis iuferioribus 

 late rotundatis, lateribus leviter divergeutibus ad basin et subretusis 

 apicem versus, angulis superioribus rotundatis et leviter productis, 

 apice subtruncato cum elevatione Itevi lata ad medium, seriebus 

 transversis duabus scrobiculorum trans centrum semiceliularum 

 (in serie unaquaque 4, srepe snbirregulariter ordinatis) ; a vertice 

 visfe oblougre apicibus obtuse acutis, scrobiculis 4 in medio utro- 

 bique ; a latere visa) subrotunda3 elevationibus latis tribus ad apicem ; 

 membrana minute punctata, pra^sertim ad angulos. Long. 44-46 /x ; 

 lat. 34-5-40 [j.; lat. apic. 25-28 /* ; lat. istbm. ll'5-12-5 //. ; crass. 

 21-23-5 [X. 



Huilla. In uliginosis editioribus prope Humpata, Empalanca 

 et Lopollo, plagas spongiosas unacum Eriocauloneis, Xyridibus et 

 Utriculariis constituens ; May 1860. No. 15. 



The apex is subrectangular with a broad elevation at each angle 

 and another elevation in the centre, the latter not being as high as 

 those at the angles. The four pairs of scrobiculations are somewhat 

 variable (cfr. t. 367, f. 4-6) ; sometimes there are three in place of 

 either or both of the two central pairs. 



2. C. suBLOBATUM (Breb.) Arch, in Pritch. In/us. 731 (1861). 

 E. ? suhlobatum Breb. in Ralfs, Brit. Desm. 91, t. xxxii. f. 4 (1848). 



Var. CRispuLUM (Nordst.) DeToui, Syll. Ahj. 1042. Enastrwu. 

 mhlohalum Breb. ft. crispulum Nordst. in Acta Univ. Lund. ix. 10, t. i. 

 f. 9 (1873). Long. 25-29 /x ; lat. 16-17 /x; lat. isthm. 4-4-5 [i ; 

 crass. 9-5 /x. This variety is probably a Euastrum. 



Huilla. Inter Utricnlariam, Morro de Lopollo ; April 1860. 

 No. 179. In paludibus exsiccandis; April 1860. No. 176. 



8. C. EETUSiFORME (Willo) Gutw. in Bot. Centmlbl. xliii. 69 

 (1890). C. Hammeri Reinsch, var. retusiforme Wille in Vid.-SeUl;. 

 Forhandl., Christiania, no. 11, 32, 1. 1, f. 16 (1880). Long. 15-16 /x ; 

 lat. 11-12 /a; lat. isthm. 3-3-5 //.; crass. 8 /x. 



Huilla. In paludibus exsiccandis ; April 1860. No. 176. 



4. C. RETusuM (Perty) Rabenh. Fl. Enrop. AUj. iii. 167 (1868). 

 Euafitrwn retusum Perty in Mittheil. Natiirforsch. Gencllsch., Bern, 

 173 (1849); non Kiitz. P/ujc. Germ. 136 (1845). Long. 30 /i; lat. 

 24 /x ; lat. isthm. 9 /x ; crass. 13-5 /x. 



Libongo. Ad margines Hum. Lifune ; Sept. 1858. No. 204. 



5. C. GRANATUM Breb. in Ralfs, Brit. Desm. 96, t. xxxii. f. 6 

 (1848). Long. 36-5-38-5 /x ; lat. 21-23 /x ; lat. isthm. 7-5 /x. 



Libongo. Ad margines flum. Lifune ; Sept. 1858. No. 204. 

 Journal of Botany. — Vol. 35. [April, 1897.] i 



