372 xvii. scytonemace.e (West). [Scytonema 
having parallel margins with long cells, others having firm irregular 
margins with somewhat torulose trichomes, consisting of very short 
transversely elliptic cells of irregular size. The latter filaments much 
resemble the branches of a Stigonema. The sheaths of this plant are 
altogether remarkable, being quite colourless, and often very irregular 
in the margin ; wherever they come in contact with each other they 
appear to coalesce, and this coalescence gives rise to a phenomenon 
(viz. the apparent inclusion of two parallel trichomes in the same 
sheath) which, so far as we are aware, has not been previously noticed 
in this genus. The branches are also most peculiar, the majority being 
solitary, and given off laterally from one cell of the primary filament 
precisely as in Hapalosiphoh. Taking into consideration all these 
points, there are still unmistakable characters which place the plant in 
the genus Scytotiema. 
2. TOLYPOTHRIX Kiitz. (1843). 
After examining the three following species, we cannot agree 
with Bornet and Flahault in separating the genera Ilassalia and 
Tohjpothrix. The former is said to be distinguished from the 
latter by its fragile filaments and its terrestrial habit. The three 
species referred to are all terrestrial as described for IfassaUia, but 
the sheaths (especially that of T. crassa) are very firm, persistent, 
and flexile, agreeing with those of Tohjpothrix. Under which 
genus ought these species to be placed ? The terrestrial habit 
points to Hassattia, the flexile and non-fragile filaments to 
Tohjpothrix. It appears to us that the only character left to 
separate the two supposed genera is the fragility of the sheaths, 
which in itself is certainly an insufficient generic distinction. 
1. T. crassa W. et G. S. West in Journ. Bot. 1897, p. 267. 
PuNGO ANDONGO. — Ad dextr. flum. Cuanza locis palustribus inter 
Lythraceas, etc. prope Candumba : March 1857. No. 11. 
2. T. phyllophila W. et G. S. West in Journ. Bot. 1897, p. 267. 
Golungo Alto. — Ad folia viva Rinorece (Alsodeice) spec, e Viola- 
cearum familia, in sylvis densis de Alto Queta ; Dec. 1855 (Sine mtmero). 
The nearest species to this is T. byssouka (Hass. Brit. Freshw. 
Alg. i. 233-4 ; ii. t. lxvii. f. 5), from which it differs in its much 
thicker colourless sheath, which is not fragile, and in the usually 
longer cells. 
3. T. arenophila W. et G. S. West in Journ. Bot. 1897, p. 267. 
PUNGO Axdoxgo. — Ad terram arenoso-humosam in editissimisrupi- 
bus Pnesidii, Pedra Cazella,cum Schizotriche delieatissima ; Jan. 1857. 
No. 151. 
4 T. limbata Thur. in Born, et Flah. in Ann. Sci. Nat. 7'' 
serie, Bot. v. 124 (1887) ; W. et G. 8. West, I.e. 
A smaller form with yellowish brown sheaths, which are often 
somewhat rough on the exterior. 
MOSSAMEDES. — Cum Oscillatoria tenuivn umbrosis muscosis ad ripam 
fluminis Bero, etiam in stagnis profundis post pluvias remauentibus 
pelliculas lsete virides natantes formans, prope Cavalheiros; Aug. 1859. 
No. 191. 
