52 ENGLISH BOTANY. 
and has a distinct tooth on the upper margin, and is much more 
convex on the lower, and in all the specimens I have seen is more — 
or less crenulated or subtuberculated on the back; the beak forms a 
continuation of the upper margin, instead of being in the middle of 
the apex. 
I am indebted to the Rev. Kirby Trimmer for fresh specimens o 
this plant. 
Hair-leaved Pondweed. 
French, Potamot a feuilles capillaires. German, Haarfirmiges Samleraut. 
Section [V.—PECTINATI. 
Leaves all similar, alternate, the uppermost ones opposite, sheathin, 
at the base, linear or setaceous, with flat vernation, 1- to 3-ribbed 
Stipules adhering to the petiole of the leaf to form the sheath 
Peduncles terminal or pseudo-lateral. Spikes few-flowered, often 
_ elongated, interrupted. 
SPECIES XXIL—POTAMOGETON PECTINATUS. 
Pirates MCCCCXXI. MCCCCXXII. MCCCCXXIII. 
Billot, F\. Gall. et Germ. Exsice. No. 3250. 
Stem cylindrical or subcompressed, slender, dichotomous or trichoto- 
mous. Leaves all similar and subtranslucent, with sheathing petioles, 
the earlier ones linear or broadly linear, the upper narrowly “Tinear | rr 
setaceous, acute, with only 1 longitudinal rib, or the lower ones W 
3 to 5 ribs, many of the leaves with 1 or 2 branches in their axi 
Stipules rather long and narrow, subscarious, united to the sheathing 
petiole of the leaf, with only the apex free. Peduncles terminal 
pseudo-lateral, longer than the spike, generally 3 to 5 times as long, 
filiform, not thickened upwards. Sepals with their lamina suborbie 
es naaes Fruiting-spike rather bats ently, interrupted, ‘ 
from ae others ; the terminal ones pe PSI Fruit large, 0 
tinged with ean a scarcely oa aha straight or slightly 
tinuation of the upper meceae Plant dull olive-green, becomi 
darker when dried. 
