ix, c, i Merrill: Plants of Guam 49 
Guam Experiment Station 197, Pago road, January 1912, locally known 
as flaniti; Costenoble 1200, in U. S. National Museum. 
A species very similar to the Philippine Freycinetia maxima Merr., and 
manifestly closely allied to that species. The fully matured leaves, how- 
ever, were not collected, but the upper inner ones differ much in shape 
from those of F. maxima Merr., being gradually narrowed upward to the 
slenderly acuminate apex, not abruptly acuminate, nor are they inflated 
at the base and with broad thin margins in the basal part as in the 
Philippine species. The fruits are somewhat smaller. 
POTAMOGETONACEAE 
DIPLANTHERA Thouars 
DIPLANTHERA UNINERVIS (Forsk.) Aschers. in Engl. & Prantl. Nat. 
Pflanzenfam. Nachtr. 1 (1897) 37; Graebner in Engl. Pflanzenreich 
31 (1907) 152. 
Zostera uninervis Forsk. FI. Aeg. Arab. (1776) 159. 
Halodule uninervis Aschers. in Boiss. FI. Orient. 5 (1884) 24; Safford 
290. 
Diplanthera tridentata Steinh. in Ann. Sci. Nat. II 9 (1838), t. 4, /. B. 
McGregor 448. 
In shallow salt water, from the Red Sea and tropical East Africa to 
Polynesia. 
POTAMOGETON Linnaeus 
POTAMOGETON MARIAN NENSIS Cham. & Schlecht. in Linnaea 2 (1827) 
228. 
Potamogeton natans Linn. var. mariannensis Nolte in K. Schum. & 
Lauterb. FI. Deutsch. Schutzgeb. Siidsee (1901) 162; Graebner in Engl. 
Pflenzenreich 31 (1907) 45; Safford 360. 
G. E. S. 231, Agana River, January, 1912. 
Duplicates of this number have been examined by both A. W. Bennett 
and C. H. Ostenfeld, who agree on the identification. The status of the 
species, however, is doubtful. Dr. Ostenfeld writes that it is certainly 
not a variety of natans where it was placed by Nolte and by Grabner and 
expresses the opinion that it probably belongs to the fluitans group in the 
neighborhood of Potamogeton nodosus Poir. (P. fluitans subsp. americanus 
C. & S.), and provisionally suggests that its proper place should be as a 
variety of Potamogeton fluitans Roth. 
POTAMOGETON LUCENS Linn. Sp. PI. (1763) 126, var. 
Potamogeton gaudichaudii Cham. & Schlecht. in Linnaea 2 (1827) 199. 
Potamogeton zizii W. F. Wight ex Safford in Contr. U. S. Nat. Herb. 9 
(1905) 260, non Koch. 
McGregor 424, in fresh water, Agana River, October, 1911, sterile. 
Duplicates of this number have been examined by both A. W. Bennett 
and C. H. Ostenfeld, who agree on the identity of the specimen with 
Potamogeton gaudichaudii Cham. & Schlecht. I have, however, reported 
the species under Potamogeton lucens Linn., following Mr. Bennett” who 
20 Ann. Conserv Jard. Bot. Geneve 9 (1905) 93. 
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