88 Potamogetones novae ab Arthur Bennett descriptae. 
Habitat. Madagascar: Environs de Tananarivo, July, 8, 1810. M. 
Goudot. Envoi recu en 1840. 
„Les eaux d'Itas, ou le chaton de fleurs de cette plante vient nager 
à la surface; la tige est trés longue.“ 
In habit allied to P. praelongus Wulf. and P. decipiens Nolte, differs 
from the former by the non-cuculate leaf apex, and the nervation is lucens- 
type, not praelongus. From the latter by the stem, stipules, and leaf-bases. 
The mid-vein is excurrent at the leaf-apex. 
2. Potamogeton perfoliatus L. var. mandschuriensis Bennett, 1. c., p. 100. 
Usually differs from the ordinary Asiatic form of the species, by 
the lighter color of the foliage, the longer internodes of the lower parts, 
the elongate undulate leaves with waved margins, much like on a small 
scale those of the N. America var. Richardsonii A. Benn. This form seems 
to prevail throughout Mandschuria, near it in Soongaria (Schrenk!) while 
the Mongolian specimens Gobi; Krighig-nor! leg. Potanin, are more like 
the thin-leaved states of the ordinary plant. Spikes thicker, with more 
numerous fruits, and the central keel (carina) is decidedly winged. I have 
seen Litwinow's nos. 405, 424, 425, 474, 2480, 3348 and 3413 which re- 
present this form. 
In Siberia and Japan the specimens are much darker in color, except 
one of Turczaninow from Ircutia 1828, which is very like the Mand- 
schurian specimens. 
The typical forms of P. perfoliatus in N. America are mostly small 
leaved. I have seen no such specimens thence as var. densifolius Meyer, 
or var. macrophyllus Blytt. The distribution of P. perfoliatus is somewhat 
peculiar. With the exception of Algeria and Marocco, I know of no African 
habitats; while in N. America it extends from 629 N, Lat., south to Florida! 
St. Lucia! and in Central America in Guatemala! Absent from S. America; 
rare in Australia; and not recorded from Polynesia. In Asia it extends 
from 700 N. Lat.! to 80 N. Lat. (Ceylon). 
3. Potamogeton asiaticus Bennett, l. c., p. 108. 
Stems terete, siriate, about 15 inches high branching only at the 
leaf-insertions, at nearly a right angle, many of the branches with 3—5 
leaves only, and agglomerated at the apex into a winter-bud, or gemmae. 
Upper (floating) leaves oblong 6 lin. long attenuated into the petiole 
(petioles 3—6 lin-long); 9-nerved with numerous cross nerves, immersed 
in the chain-like areolation which completely covers the leaves, and is 
continued down the petiole on either side. Accompanaying these oblong 
leaves are others, linear-attenuate, with the structure of the lower leaves, 
an unusual occurance. 
Middle (submerged) leaves linear-lanceolate acuminate; 10—14 lin. long. 
Lower (submerged) leaves linear-setaceous 7-nerved, nerves not reach- 
ing the margins, but forming a compact central network of nerves with 
elongated interspaces; variable in length. 
Stipules evanescent, scarcely to be found except at the extreme apex 
of the stems, broad, 5 lin. long. 
