142 Rhodora [AveusT 
tenui, membranacea, aequali, hyalina; heterocysta basali globosa, 
vel superne subapplanata, 5-6 u diam., interdum solitaria, vulgo sub 
heterocysta cylindrica, apicibus rotundatis, 7-8 X 10-17 u, haud 
raro duo, raro tres seriatis super heterocystam basalem; heterocystis 
intercalaribus? sporis? 
Filaments neither thickened nor attenuate, straight or subflexuous, 
sometimes erect, usually prostrate; trichome 6-7 u diam., cells as 
long as broad or slightly more or less; lower cells cylindrical, indistinct; 
upper cells rounded, moniliform; sheath thin, membranaceous, even, 
hyaline; basal heterocyst globose, or somewhat flattened above, 
5-6. diam., sometimes solitary, commonly below a cylindrical 
heterocyst with rounded ends, 7-8 X 10-17 u, frequently two, rarely 
three such heterocysts in a series above the basal heterocyst. Inter- 
alary heterocysts and spores not observed. On leaves of Sphagnum 
and other water plants, occasionally on Oedogonium, Tarpaulin Pond, 
August, 1917, Miss J. M. Furber. Type in Collins herbarium. 
On the Sphagnum leaves the prostrate filaments usually run length- 
wise, either up or down; often two basal heterocysts will be in close 
contact, the filaments of both forming a straight line, giving the effect 
of one filament with two intercalary heterocysts. On Ocdogonium 
Borisianum the filaments wind spirally about the host filament. 
Hapalosiphon pumilus and H. hibernicus occur with it, but lack the 
purplish shade of the Microchaete, and of course are amply distinct 
in branching. 
BuLBocHAETE Furberae n. sp. Dioecia, nannandria, gynandro- 
‘spora; oogoniis depresso-globosis, sub seta terminali, patentibus 
(interdum adparenter erectis); dissepimento infimo; oosporae 
episporio scrobiculato; androsporangiis sparsis, 1—9-cellularibus, 
nannandriis ad oogonium, antheridio interiori, stipite valde curvato, 
antheridio breviore. 
Dioecious, nannandrous, gynandrosporous, oogonium depressed- 
globose, below terminal seta, patent (sometimes apparently rect); 
dissepiment very low; epispore of oospore scrobiculate; androspor- 
angia scattered, 1—9-celled nannandria on oogonium; antheridium 
interior, stipe strongly curved, shorter than the antheridium. 
Wood Pond, Woods Hole, Massachusetts, Aug., 1917. Miss J. M. 
Furber & I. F. Lewis. Type in Collins herbarium. 
Veg. cell, 10-15 u diam., 3-5 diam. long. 
Oog. 36-43 u diam., 27-34 u long. 
Andr. cell, 9-10 u diam., 8-9 uw long. 
Nann. 7-8 yw diam., 20-25 u long. 
The oogonium is occasionally on one of the lower cells of a branch, 
but more commonly on the upper cell; usually this cell bears a seta 
