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1925] Setchell-Gwrdner: Melanophyceae 473
7. Compsonema Kuek.
Fronds forming small cushions more or less circular in outline.
composed of a prostrate creeping, primary portion, giving rise to
numerous erect unbranched or branched filaments, with or without
hairs; prostrate portion monostromatic, composed of filaments quite
regularly radiating from a common center and usually with sub-
terminal branching, closely crowded ; reproduction by unilocular
zoosporangia and plurilocular gametangia with mostly pluriseriate
loculi.
Kuckuck, Beitriige zur Kennt. Meeresalg., 1899, pp. 56-58 (90-92
inrepr.),pl. VI (12), figs. 6-9.
The type species of Compsonema is C. gracile and the type locality
is Rovigno, on the east coast of the Adriatic Sea, where it was found
growing on stones in water 1-2 meters deep.
The genus Compsonema was established by Kuckuck. We have
accepted the genus to include forms which, like Myrioncma, start from
a single cell that, by divisions, soon originates a series of closely
crowded, radiating filaments, forming a monostromatic basal layer
more or less circular in outline; and which, unlike Myrionema, pro-
duce on erect filaments numerous gametangia that develop pluriseriate
loculi. The genus is very closely related to the genus Myrionema on
one side and to Hecatom ma on the other.
Key to the Species
1. Erect sterile filaments branched 2
1. Erect sterile filaments simple 5
2. Creeping filaments with few subulate rhizoids 7. C. fasciculatum (p. 478)
2. Creeping filaments without rhizoids 3
3. Sterile branches short, high up, secund 4
3. Sterile branches long, low down, not secund 13. C. intricatum (p. 482)
4. Erect filaments piliferous in part 17. C. ramulosum (p. 484)
4. Erect filaments not piliferous 12. C. sporangiiferum (p. 481)
5. Gametangia all terminal 6
5. Gametangia terminal and lateral or intercalary 14
6. Gametangia all sessile 7
6. Gametangia pedicellate or in part sessile 8
7. All erect filaments completely transformed into gametangia. ...2. C. sessile (p. 474)
7. Gametangia intermixed with sterile filaments 6. C. tenue (p. 478)
8. Prostrate filaments producing penetrating rhizoids 9
8. Prostrate filaments not producing rhizoids 10
9. Rhizoids abundant, straight, penetrating deeply into the host
11. C. streblonematoides (p. 481)
9. Rhizoids contorted, not penetrating deeply 5. C. pusillum (p. 477)
10. Gametangia very abundant, of uniform height .4. C. fructuosum (p. 476)
10. Gametangia with pedicels very variable in height 11