MONANDRIA. DIGYNIA. = 3 
lantica, p. 2. observes also that there are 1 or 2 stamens 
_ in this genus. ; 
4. HIPPURIS. ZL. (Mare’s-tail.) = 
Calix obsolete, entire, above the seed. Corol- 
_ la 0, Style received in a groove of the anther! 
(stamen seated upon the style?) Stigma simple. 
Seed 1. 
‘Hasitvs. Stem cylindric, simple; leaves verticillate, 
entire; flowers around the axill. 
Specres. 1. H. vulgaris? but the leaves are mostly by 
sixes in the European plant, not by eights (in fresh water 
ponds and ditches; rare). The H. maritima of Sweden and 
_ Finland grows on the sea-coast. 
‘Oxs. The Hippuris appears to be the simplest phzno- 
_ §amous plant in nature; and stands without any distinct — 
"affinities to other genera. : 
Order 2.—DiGyn1A. 
5. CALLITRICHE. L. (Water-star.)- : 
_ Calix inferior. 2-leaved. Corolla 0. Seeds 4, _ 
naked, compressed. 3 Seeds 
ie opposite, flowers axillary, (in C. verna monoi- 
8. 
_ Species. 1. C. verna.2. autumnalis? The C. vernais re- ~ 
-markably polymorphous, the leaves vary from the places 
where they grow; sometimes it produces 2 stamens, and 
fee Be in some instances the flowers are hermaphrodite. The _ 
leaves of the calix are described by Desfontaines as be- 
~ ing concave, and lunate, with the filament as long as the 
- calyx; in the American plant, ( C. heterophilla of Pursh,) - 
- the stem is compressed, and _bifistulous, fur floating; the \ 
_ lower branches with narrower and often emarginated 
_ leaves, producing only male or female flowers, the central 
~ branches with retuse, spathulate oval, 3-nerved leaves, 
uring those which are hermaphrodite, with the stamens 
much exserted. | goer? 
CORISPERMUM. L. (Tick-seed.) 
Calix 2-parted. Corolla 0. Sced 1, plano-con- _ 
= 
VOX, oval, and naked, with an acute circular 
margin, ne eee 
