314 



PONTEDERIACEiE. 



Heteranthera. 



Stem much branched, varying in length with the depth of the water, rooting at the lower 

 joints. Leaves 2-8 inches or more in length, and 1-3 lines wide. Spathe about an inch 

 long, acuminate. Perianth with a very long slender tube, which is somewhat curved : segments 

 of the border equal, lanceolate-linear, pale yellow. Stamens more than half the length of the 

 perianth, usually 3 but sometimes 4, a little unequal : filaments somewhat dilated : anthers 

 yellow, narrowly oblong, sagittate at the base. Ovary incompletely 3-celled, conical-lanceolate, 

 tapering into a long slender style, which, above the tube of the flower, is thickened and some- 

 what clavate : stigma small, consisting of 3 hairy spreading lobes. Ovules numerous, erect. 



Flowing waters : frequent. Fl. July - August. Fr. September. This species differs 

 so much from the preceding in character and habit, that I should have adopted the genus 

 Schollera of Willdenow, were it not that Het. zosterifolia of Martius connects it with the 

 present genus. 



Order CXIX. MELANTHACEvE. R. Brown. The Colchicum Tribe. 



Flowers often polygamous or dioecious. Perianth more or less colored, 6-leaved 

 or deeply G-parted, regular, mostly persistent; the aestivation often involute. 

 Stamens 6 (in Pleea 9 - 12): anthers extrorse, or very rarely introrse. Ovaries 

 3, more or less united : styles distinct, stigmatose on the inside, or with a simple 

 stigma at the summit. Ovules in a double series, ascending, anatropous. 

 Capsule membranaceous or coriaceous, more or less completely separable into 

 3 carpels, and dehiscing at the ventral suture, sometimes loculicidal. Seeds 

 5 - 20 (rarely 2) in each carpel, angular or compressed : testa membranaceous, 

 often winged or margined. Embryo small, in fleshy albumen; the radicle next 

 the hilum. — Perennial herbs, with simple stems or scapes arising from corms, 

 bulbs, or a horizontal rhizoma. Leaves sessile, linear or dilated, more or less 

 clasping or sheathing at the base. Flowers mostly in racemes, panicles or 

 spikes, sometimes solitary or fasciculate. 



CONSPECTUS OF THE GENERA. 



1. Anthers spuriously one-celled, shield-form after dehiscence. 



* Leaflets of the perianth bearing 2 glands, which are sometimes connate. 



1. Zygadenus. Flowers perfect. Leaflets of the perianth without claws. Filaments free. 



2. MEf.ANTHiUM. Flowers mostly polygamous. Filaments inserted on the claws of the perianth. 



** Leaflets of the perianth without glands or claws. 



3. Veratrdm. Flowers polygamous, in compound racemes. Stamens shorter than the perianth. 



2. Anthers 2-celled. 



4. Helonias, § Chamjeliritjm. Flowers dioecious. Filaments not dilated. Capsule ovoid, many-seeded. 



