CXLIl. LEMNACE^. 838 



inJourn. Bomb. Nat. v. 13 (1901) p. 428; Prain, Beng. PL p. 1117. 

 Lemna gJobosa, Roxb. Hort. Beng. (1814) p. 66; Grab. Cat., p. 252; 

 Dalz. & Gibs. p. 281. Lemna arrliiza, Linn. Mautiss. 2 (1771) p. 294 ; 

 Sjme, Eng. Bot. ed. 3, v. 9 (1869) p. 24, t. 1398. 



Tanks throughout the Presidency common, covering the water like a green scum. 



Oedee CXLIII. ALISMACE^. 



Aquatic or marsh herbs, usually erect, sometimes floating. Leaves 

 radical or clustered at the nodes of floating stems, entire, petiolate, often 

 pellucid-dotted or lineolate. Flowers pedicellate, regular, 1 -sexual or 

 hermaphrodite, in umbellate or paniculate whorls, usually white or 

 pink ; bracts 3 or more, membranous ; bracteoles small. Perianth- 

 segments 6 in 2 series, the 3 outer {sepals) herbaceous, the inner 

 whorl petaloid, rarely obsolete. Stamens 6 or more (i-arely 3), 

 hypogynous or perigyuous ; anthers erect, basifixed, 2-celled, dehiscing 

 by lateral or dorsal longitudinal slits. Carpels 3-6 or moi^e, 1-celled, 

 sessile or stipitate on a flat or raised receptacle ; ovules 1 or more in 

 each carpel ; placentas on the inner angle (rarely ovule solitary and 

 basal) ; style long or short (rarely 0) subterminal or ventral ; stigma 

 simple. Fruit of small achenes or follicles. Seeds small or minute ; 

 albumen ; embryo straight or conduplicate. — Disteib. Genera 12 ; 

 species about 60, cosmopolitan. 



Fruit indehiscent of 3 or more achenes. 



Flowers polygamous ; stamens 6 ; receptacle flat 1. Limnophyton. 



Flowers 1-sexual ; stamens usually many (rarely as few as 



6); i-eceptacle globose or oblong 2. Sagittaria. 



Flowers monoecious ; stamens 3 ; receptacle small, tumid . 3. Wisneria. 

 Fruit dehiscent of 6-7 follicles; stamens 8-12; flowers 



hermaphrodite 4. Butomopsis. 



1. LIMNOPHYTON, Miquel. 



A scapigerous stemless palustrine perennial herb with milky juice. 

 Leaves sagittate, erect. Flowers polygamous (male and hermaphrodite), 

 white, in paniculate whorls. Scapes stout. Eeceptacle flat. Sepals 3, 

 herbaceous, persistent. Petals 3, membranous, deciduous. Stamens 

 6 iu 2 series, largest in the male flowers ; filaments compressed. 

 Carpels 15-20, obsolete in the male flowers ; ovule solitary, anatropous, 

 basal ; stigma small on a ventral style. Fruit of several compressed 

 or turgid hard achenes. Seeds erect, basal ; testa membranous ; embryo 

 horseshoe-shaped. — Disteib. Asia and Tropical Africa; species 1. 



1. Limnophyton obtusifolium, 3Uq. Ft. Lid. Bat. v. 3 (1855) 

 p. 243. llootstock short, stout, with numerous long root-fibres. 

 Leaves all radical, 6-12 by 4-8 in. (sometimes as broad as long), 

 reniformly or deltoidly sagittate or triangular, acute or subobtuse, or 

 with rounded tip ; basal lobes long, tapering to a fine point, spreading, 

 as long as the rest of the blade, the sinus very broad, open ; primary 

 nerves 6-8 pairs, radiating from the top of the petiole, with irregular 

 reticulate venation between them; petiole 1-3 ft. long, stout, stiiate, 

 channelled above. Panicle with a stout angular scape 2-4 ft. long ; 

 branches long, erecto-patent, the lower branches usually in 4 whorls ; 

 'bracts whorled, broadly ovate-lanceolate, acuminate, with many parallel 



YOL. II. 3 I 



