104 Rhodora [JUNE 
vey); Kittery, common! N. H.: North Woodstock! Noone’s Station! 
Mass.: Near Salem (Bailey); Amherst (W. West); Reading! Plain- 
ville! Carver's Pond, Bridgewater! Long Pond, Tewksbury! Nan- 
tucket! 
P. 'TRABECULA forma GRANULATUM G. S. West, Jour. Bot., Vol. 
XXXVII, 1899, p. 113, Pl. CCCXCVI, fig. 6. “Cell wall distinctly 
and irregularly granulate.” Length 505 p; breadth at base of semi- 
cells 34 x; apex 28 y.— N. H.: Mt. Moosilauke! 
P. 'TRABECULA forma CLAVATUM (Kütz.) W. & G. S. West, Bot. 
Trans. Yorks. Nat. Union, Vol. V, 1902, p. 58.  Docidium clavatum 
Kütz. in Ralfs, Brit. Desm., 1848, p. 156, Pl. XXVI, fig. 3; Wolle, 
Desm. U. S., 1884, p. 48, PL IX, fig. 8. “Cells about 12 times longer 
than their diameter; semicells slightly tumid and subclavate." Length 
360 u; breadth at base, 31 x; apex 25 j.— Mass.: West Bridgewater! 
P. ''RABECULA var. RECTUM (Delp.) W. & G. S. West, Brit. Desm. 
Vol. I, 1904, p. 212, Pl. XXX, figs. 9-10.  Pleurotaenium rectum 
Delp., Mem. R. Accad. Scienze di Torino, ser. 2, Vol. XXX, 1877, 
p. 129, Pl. XX, figs. 8-11. Cells smaller than the typical, 12-15 times 
as long as wide. Length 250 4; breadth at base of semicells 18.5 p; 
apex 15 j.— N. H.: North Woodstock! Mass.: North Eastham (F. 
S. Collins)! 
P. suBGEOoRGICUM Cushman, Ruoponma, Vol. VII, 1905, p. 117, 
Pl. LXI, fig. 4. Cells large, 12-15 times as long as wide, semicells 
widest at a point more than midway from the isthmus, thence taper- 
ing gradually to either end; basal portion with several inflations, 
remaining portion of the sides smooth; apex truncated, with a crown 
of 10 bluntly rounded tubercles. Length 600-700 u; breadth at base 
30-35 u; at middle of semicells 45-58 «u; apex 25-30 j.— N. H.: 
North Woodstock! 
P. Maximum (Reinsch) Lund., Nova Acta Reg. Soc. Scient. Upsala, 
ser. 3, Vol. VIII, 1871, p. 89. Docidium maximum Reinsch, Spec. 
Gen. Alg., 1867, p. 140, Pl. XX. C, figs. 1-2. D. Archeri Wolle, 
Desm. U. S., ed. II, 1892, p. 51, Pl. XII, fig. 2. Cells large, 14-18 
times as long as wide; apices truncate with rounded angles; promi- 
nent basal inflation. Length 600-850 4; breadth at base 40-55 pn; 
apex 22-30 4.— Me.: Orono (W. West). Mass.: Amherst (W. West). 
P. inpicum (Grun.) Lund., Nova Acta Reg. Soc. Scient. Upsala, 
ser. 3, Vol. VIII, 1871, p. 90. Docidium indicum Grun., Desmid. 
Banka, 1865, p. 13, Pl. II, fig. 18. Length 630 u; breadth at base 
