388 CXXIX. NAIADER. 
Z. palustris is a small, much-branched, submerged plant. Leaves scat- 
tered, narrow-linear, flat. Stipules broad, amplexicaul.—Found in ponds, 
ete., in various parts of the colony; and in most parts of the world in 
similar situations. 
4. ZOSTERA, Linn. 
Flowers moneecious. Spathe longitudinally splitting from 
the lower part of the leaf, produced into a lamina above. 
Spadix plano-compressed, membranous, nude at back, in front 
covered with alternately 2-seriate stamens and ovaries. An- 
thers oblong, subsessile, 1-celled; pollen confervoid. Carpels 
fewer than the anthers, 1-celled; style subulate, persistent ; 
stigmas 2, capillary. Utricles membranous.—Kwnth, l.c. p. 
115; Hndl. Gen. n. 1659. 
Z. marina (Sea-Grass) grows in the sea, on sandy shores all over the 
world. Root creeping. Leaves linear, obtuse. - 
Orper CXXX. AROIDER. 
Flowers unisexual, rarely bisexual, sessile on or sunk in a 
spadix, which is either nude or invested with a petaloid spathe ; 
when (in Lemna) the flowers are subsolitary, the spadix is ob- 
solete. Perianth 0 or 8-4—6-parted, scale-like. Stamens defi- 
nite and opposite the lobes of the perianth or indefinite or 
solitary, hypogynous; anthers 1—2- or many-celled, opening 
outwards. Ovary single, free, 1- rarely 3-celled; ovules soli- 
tary or several, ascending or pendulous. Fruit mostly succu- 
lent, rarely dry, indehiscent, 1-many-seeded. Embryo in the 
centre of fleshy or floury albumen; plumule 2-3-leaved.— 
Mostly herbaceous plants, with acrid juices, and creeping or 
tuberous rootstocks. Leaves usually petioled, with expanded, 
ovate, sagittate or pedate-nerved leaves, and simple scapes 
bearing undivided spadices. The more reduced forms of the 
Order (as Lemna and Pistia) are small floaters. 
Tall herbs. Spathes white, convolute at base. . . . 1. RICHARDIA. 
Terrestrial herbs. Spathes green, tubular at base . . 2. STYLOCHITON. 
Floating herbs, with sessile, rosulate leaves . . . . 3. PISTIA. ° 
Minute floating green scales . . . . .. . . . 4 LEMNA. 
1. RICHARDIA, Kth. 
Spathe convolute at base; limb expanded, marcescent. 
Spadix cylindrical, everywhere very densely covered with 
flowers, the lower part pistilliferous, with imtermixed club- 
-shaped staminodia, the rest altogether staminiferous. Anthers 
many, free, sessile, 2-celled ; the cells attached to a broadly 
