326 oxxvi. SALiciNEiE (Skan). [Populus. 



in Notizbl. Kon. Bot. Gart. Berlin, ii. 217, in Sitzungsber. Preuss. 

 Akad. Wiss. 1904, 369, and in Engl. Jahrb. xxxvi. 252 ; Aschers. in 

 Ber. Deutsch. Bot. Gesellsch. xxvia. 360. 



Nile Land. British East Africa : along the Tana River, from 1500 ft. to 

 sea-level, Battiscombe, 207 ! Korokoro, Thomas ; Witu, Tliomns, 49 ! on the 

 banks of the Athi and Tsavo Rivera, Hildebrandt, 2008 ! 



Order CXXVII. CERATOPHYLLEiE. 



(By S. A. Skan.) 



Flowers monoecious. Perianth thinly herbaceous or sub mem- 

 branous, equal ; segments 6-12, subvalvate, often toothed or lace- 

 rated at the apex. Male : Stamens 10-20, crowded on a flat or 

 convex torus ; filaments very short ; anthers linear-oblong, equalling 

 the perianth ; cells 2, linear, parallel, adnate, dehiscing longitudinally ; 

 connective produced beyond the cells into a thick coloured usually 

 2- or 3-toothed appendage. Female : Ovary 1, sessile, ovoid, 1- 

 celled ; style terminal, linear-subulate, persistent ; stigma unilateral ; 

 ovule 1, pendulous, anatropous. Fruit 1-seeded, leathery, inde- 

 hiscent, ovoid or ellipsoid, somewhat compressed, tipped with the 

 hardened style, sometimes with 2-4 spreading or reflexed spines at the 

 base, wingless or surrounded by a narrow or broad leathery toothed 

 wing, smooth or tuberculate. Seed pendulous ; testa membranous ; 

 albumen ; embryo straight, with oblong rather thick equal cotyle- 

 dons ; radicle very short ; plumule large, many-leaved. — Aquatic 

 herbs with elongated leafy floating branches. Leaves verticillate, 

 2-fid or dichotomously divided ; segments linear or filiform, some- 

 what rigid, usually toothed. Flowers axillary, solitary, very small, 

 sessile, the male and female alternating at the nodes, or male at the 

 lower and female at the upper. 



Ceratophyllum, the only genus, includes 1 or 2, or, according to some 

 authorities, about a dozen species, growing in fresh water in nearly all parts 

 of the world. 



1. CERATOPHYLLUM, Linn. ; Benth. et Hook. f. Gen. Pl.iii. 415. 

 Characters and distribution of the Order. 



1. C. demersum, Linn. Sp. PI ed. i. 992. A glabrous perennial 

 herb. Stems much-branched, floating and submerged, 2-3 ft. or 



