REVISION OP THE GENUS NAJAS. 419 



with 10 to 22 marginal teeth, consisting of a sharp ascendinc^ spine on a shallowly 

 triane^ular base. Intravai?inal scales '5 mm. loner. Flowers on very short shoots on the 

 branchlets, each with a few flowers ; male and female occur on the same shoot, Male 

 1"8 mm. long, anther dehiscing in the iisiial way ; pollen-grains oblong. Female 

 probably about the same length before pollination, characterized by the stout cylindrical 

 style and short, generally unequal, stigmas. Fruits usually in pairs on the reduced 

 fertile shoots, about 1 mm. long, the thin pericarp, in the dry state, closely conforming 

 to the testa and showing about 20 rows of well-marked squarish pits. 

 India — Assam [Jenkins, in Herb. Kew.) ; Calcutta (Herb. Hook. 1867). 



24. Najas tenuifolia, E. Br. (PI. XLII. figs. 158-162.) 

 N^tefiuifolia, R. Br. Prodr. 345 (1810) ; Kunth, Enura. iii. 114 (1841) ; Benth. Fl. Austral, vii. 181 



(1878). 

 N. graminea var. tenuifolia, A. Br. in Journ. Bot. ii. (18(54) 278. 



Planta caulibus s^pe erectis vel basi repentibus, ramis brevioribus ascendentibus, saepe 



magis elongatis et laxius foliatis ; foliis planis ascendentibus, anguste linearibus, 



acutis, vel, setaceis, margine denticulis numerosis ascendentibus instructa ; vagina 



angusta longe auriculata ; sqiiamulis intravaginalibus subulato-filiformibus ; jlorihus 



solitariis, masculis breviter pedicellatis, spatha ovoidea in collum breve ore longe 



spiniferum desinente, anthera quadriloculari ; ovario nudo, stylo cylindrico in 



duo stigmata diviso ; pericarpio ad semen oblongum vel ellipsoideo-oblongum arete 



applicito ; testa in areolis minutis quadratis regulariter lineata. 



Plants often between 11 cm. and 24 cm. high, apparently erect from the base or 



creeping and rooting at the lower nodes, the ascending branches shorter than the main 



stem, and giving the w'hole a spreading tree-like habit, more or less dense above ; the 



lower internodes 2 cm. long by '75 mm. broad, becoming gradually shorter to 1'5 cm. in 



the upper part, and filiform. Often, however, the shoots are longer (to 32 cm.), spreading 



laxly and flexuose, with internodes 4 to 5'5 cm. long, diminishing to 25 to 1*5 cm. a few 



centimetres below the apex, with a width of from "7 mm. below to '5 mm. or less 



above. Leaves weak, thin, flexuose, tapering to an acute apex, often setaceous above, 



2'5 to 3'5 cm. long by 5 to '75, or nearly 1 mm. greatest breadth. There is a row of 



long, slender, colourless fibres beneath the epidermis at the margin, which bears on each 



side generally 18 to 20 slightly projecting teeth. Sheaths small and narrow (3 mm. 



long), bearing large triangular auricles more than a third of the whole length, with 



numerous subprominent suberect teeth, chiefly on their outer margin. Intravaginal 



scales "75 to '8 mm. long. 



Male floicers very rare (only one found after repeated search) ; spathe close-fitting, 

 neck with several long sharp spines at the mouth ; anther apparently four-celled. 

 Female flowers 2 mm. long, the short ellipsoid ovary passing into a tapering cylindrical 

 style. Fruit, when dry, consisting of a membranous pericarp bearing the withered style. 

 Seed 2*3 mm. long by '5 in diameter; raphe prominent in the lower half; testa with 

 about 30 rows of small quadrate areolae with thick separating walls, arranged in regular 

 longitudinal series ; near the tip and the raphe they become polyhedral and less 

 regular in shape. 



SECOND SERIES. — BOTANY, VOL. V. 3 S 



