270 MR. W. WEST OlS SOME TEESHWATEK 



ference being in the branclies not being aggregate. The hetero- 

 cysts vary from subquadrate to subrotund, and are rather 

 numerous. 



19. SCTTONEMA AMPLUM, nOV. Sp. (PI. XVI. figS. 14-16.) 



S. strato parvo, pannoso, 3-5 mm. lato, fusco ; filis dense iii- 

 tricatis ; pseud oramis sparsis plerumque gemiuatis sed interdum 

 singulis, filo priraario tenuioribus ; vaginis amplissimis stralis 

 parallelis formatis, in parte exteriore gelatinoso-achrois vel sub- 

 luteolis, in parte interiore abrupte luteo-fuscis ; trichomatibus 

 angustis, luteo-viridibus, ad apicem pseudo-ramulorum crassior- 

 ibus et articulis brevioribus ; articulis diametro S^-Gplo (ple- 

 rumque 4plo) longioribus ; heterocyatis oblongis, diametro 3-3|plo 

 (rarius 2plo) longioribus. 



Crass, fil. prim. 19-24 /z ; crass, ramul. 13*5-16 /j. ; crass, trich. 

 3-5-4 /x. 



Hab. On trees, summit of Trois Pitons (4500 ft.), Dominica. 

 Nos. 903 and 901-. Growing about and upon the surface of 

 Symploca cuspidata, n. sp. 



The nearest species to this with regard to the comparative 

 length and breadth of the cells is S. ambigimm, Kuetz., from 

 which it differs in its much larger size, stouter habit, compa- 

 ratively broader sheath, and in the more unfrequent branches. 

 The branches are usually geminate though not unfrequently 

 single, and they are always thinner than the primary filament. 

 The trichomes at the apices of the branches become almost 

 twice as thick, the cells becoming very much shorter. S. mijo- 

 chrous, Ag., is somewhat similar though larger, and has not 

 such a comparatively broad sheath, and the latter is ocreate. 



20, S. AMBIGUUM, Kuetz. {Species Algaruin, p. 894 ; Tabulcs 



phjcolog. ii. p. 7, t. 26. f ii.) (PL XY. figs. 11-15.) 



Crass, fil. 9'5-11'5/Lt; crass, trich. 2-2*5 /i. 



Hab. On trees, summit of Trois Pitons (4500 ft.), Dominica. 

 No. 903. On the ground, mostly in old Diablotia holes, Morne 

 Anglais (2300 ft.) (15-7-92.) No. 493. AmoT\^&t Symploca. 



The figure given by Kuetzing (/. c.) is very indistinct ; but the 

 specimens agreed well with the description given by Bornet and 

 riahault (Eevis. des Nostoc. Ilcterocyst. p. 100), excepting that 

 the filaments were a little thicker (9"5-ll*5 ^i against 6-9^/). 

 The trichomes were, however, the same. One of its chief 

 characters is its long and narrow cells, which get shorter 

 and thicker (up to 3-8 /u) towards the apices of the young 



