■ 



NOTES ON POTAMOGETONS. 227 



" Sagina Boydii, n. sp. — Perennial, quite glabrous, densely 

 tufted, the internodes so shortened as to be scarcely visible ; leaves 

 crowded, regularly recurved ; terminal rosette barren, lateral 

 branches very short, crowded, producing flowers in the axils of 

 the leaves ; peduncles erect, about as long as the leaves ; flowers 

 pentamerous or tetramerous ; sepals always more or less erect ; 

 petals none ; styles very short, widely separated at the base ; 

 capsule globose, shorter than the sepals. 



11 Forming dense cushions. Subterranean stem much branched, 

 rooting. The aerial portion of the stem erect, about half an inch 

 high, below which the stem is clothed with decaying leaves. Apex 

 of the stem forming a barren rosette, surrounded by very short 

 lateral branches. Leaves so closely imbricated that the internodes 

 are invisible, about a quarter of an inch long, rather fleshy, rigid, 

 widely and shallowly channelled above ; midrib rather prominent 

 below, tip with a short ruuero, strongly and regularly recurved, 

 dark shining green. Peduncle one- flowered, and with the flower 

 about as long as the leaves, narrowed upwards, quite glabrous. 

 Flowers erect, or nearly so. Flowers pentamerous or tetramerous. 

 Sepals rather unequal, widely ovate, blunt, concave on the inner 

 side, never spreading, scarcely veined, of a paler green than the 

 leaves, margin very narrowly paler and submembranous. Petals 

 none. Stamens opposite the sepals, longer than and incurved over 

 the ovary ; anthers oval, the cells a little divergent at the apex. 

 Ovary globose, flattened at the apex, which is covered by a cluster 

 of about 11 or 12 semiglobular shining pale yellow papillae, round 

 which cluster is a slightly thickened rim (with 5 or 4 points and 

 5 or 4 angles) to the flattened apex of the ovary. Styles 5 or 4, 

 situated within the points of the thickened rim, their bases separated 

 by the cluster of papillae, very short, flattened; all the upper surface 

 stigmatic, projecting horizontally. Capsule globose, shorter, and 

 covered by the sepals ; valves 5 or 4, opposite to the sepals, valves 

 entire at the tip. When the capsule opens, the flattened top falls 

 away. Seeds few, minute, dark brown, formed like others of the 

 genus, and covered with flattened tubercles." 



NOTES ON POTAMOGETONS. 

 By Arthur Bennett, F.L.S. 



(Continued from Jouru. Bot- 1891, 307.) 



Potamogeton serotinus " Schrad. in liit," ap, Koch, Syn. Fl. 

 Germ. ed. 2, p. 775 (1844), P, natans j3. prolixus Koch, L c. P. 



uj u$t if olios 



I Fr. Nov, Fl. Snec. ed, 2, p. 28 (1828). P. natans 

 Meyer, Chi, Hann. p. 519 (1836). P. natans /}. 

 antfustifolius Led. Fl, Ross, vol. iv. p. 23 (1853), P f spathnlatus 

 Nolte/Nov. Fl. Hols, p, 17 (1826), fide Prahl. — According to an 

 authentic specimen, u assentiente eel, Nolte," this seems to belong 

 to natans, but I have seen no specimens in fruit, Material i3 

 wanting to prove whether it is more thau a state of natans, 



q2 



