362 MR. JAMES GROVES : 
Plants minute, diameter of whorls usually not exceeding 
10 mm, Stem and branchlets extremely slender and 
flexuous. — Branchlets usually 8 in a whorl, twice 
and occasionally 3 times forked. Daetyls very long 
and slender, lower cell tapering to the apex. Gamet- 
angia produced at the first and occasionally at the 
second forking. Oospores 225-300 y long, showing 
6-8 broadly-flanged ridges ou... nn. 
Gametangia not produced at first fork of the branchlets, 
Plant small, slender. Whorls distant, branchlets 
usually 6, short and rather rigid. Oospores c. 200-250 u 
long, showing 7-8 low ridges. Membrane with con- 
spicuous beaded large-meshed reticulation .............., 
Dactyls (at least some of them) very short and divergent, 
and arising from a sterile node. 
Coronula short, the upper cell not much longer than the 
lower. 
Oogonia solitary. 
Daetyls varying much in length, some not abbreviated 
and divergent. Oospores e. 250-400 a long......... 
Dactyls extremely short, the lower cell often not much 
longer than broad.  Oospores c. 200—220 u long ... 
Oogonia clustered. Dactyls mostly short and divergent. 
Oospores usually e. 250 p long en. 
Coronula elongate, some or all of the upper cells prolonged 
into a sharp point 
EE TEM 
Dactyls 2-3-celled, ultimate cell allantoid. Dicecious.  Fruitin 
y 8 
heads enveloped in a mucous cloud 
Ce ee ses soa oe 
Branchlets in each whorl in 3 series, those of the central series much 
longer and more compound than those of the upper and lower 
Moneeeious. Young fertile whorls enveloped in a mucous cloud 
2, TOLYPELLA, 
Ultimate cells of branchlets conical .............. ec 
Stem stout. Sterile branchlets simple, much elongated. Oospore mem- 
brane very thin, Antheridia e. 300 x in diameter 
Ultimate cells of branchlets allantoid .........0000 00 nn. 
Diecious. [Oospores e. 250-300 x long]. Antheridia e. 700 u in 
diameter 
Monecious. Oospores e, 300-375 u long. Antheridia c. 325-375 u in 
diameter... . 
3. NITELLOPSIS, 
Diæcious. Plant very large. Branchlets > 10 em. long, of 2-3 segments: 
ultimate segment elongated. Oogonium c. 1200-1400 u long, 1000- 
1200 y thick ; coronula small, Nitella-like. Antheridium c. 1000 a in 
diameter. Producing large star-like bulbils 
LIP donnes ssssst nn nesss 
4. LYCHNOTHAMNUS, 
Moneecious. Stem imperfectly corticate. Stipulodes in a single cirele, 
very long. Oogonium produced usually between two antheridia 
m 
e 
> 
l. bratrachosperma. 
9. N. tenuissima. 
11. N. oligospire. 
12. N. mieroglochin. 
13. N. microcarpa., 
14. N. furcata. 
15. N. sp. (N. myrio- 
iricha prox.). 
Heteroclemæ. 
16. N. hyalina. 
Conoidez. 
l. T. prolifera. 
Allantoideæ. 
2. T. hispanica. 
3. T. glomerata. 
l. N. obtusa. 
l. L, barbatus. 
