335 
Alliance V. HYDRALES. 
Essential Character. — Calyx calycine. Petals petaline. Stamens more numerous 
than 6. Albumen always absent. 
Order CCXLII. HYDROCHARACE^. The Frog-Bit Tribe. 
Hydrocharides, Juss. Gen. 67. (1789). — Hydrocharide.®, DC. FI. Fr. 3. 265. (1815) ; 
R. Brown Prodr. 344. (1810) ; Richard in Mem. Mus.\o\. 1. 365. (1815) ; Agardh 
Aph. 127. (1822); Lindley’s Synopsis. 254. (1&29). — VALLisNERiACEiE anrf Stra- 
TiOTEiE, Link Handb. 1. 281. (1829). 
Essential Character. — Flowers hermaphrodite or unisexual. Sepals 3, herbaceous. 
Petals 3, petaloid. Stamens definite or indefinite. Ovary single, inferior, 1- or many- 
celled ; stigmas 3-6 ; ovules indefinite, often parietal. Fruit dry or succulent, indehis- 
cent, with 1 or more cells. Seeds without albumen ; embryo undivided, antitropous. — 
Floating or water-plants. Leaves with parallel veins, sometimes spiny. Flowers spa- 
thaceous. 
Affinities. These water-plants are readily distinguished from all other 
monocotyledons by their tripetaloideous flowers, with an inferior ovary ; by 
this they are separated from Alismacese, with which they agree in habit and 
want of albumen, but from which they also differ, as Pomese and Ranun- 
culacese, in the carpels being definite, not indefinite. Commelinaceae are at 
once recognised by their superior trilocular ovary. Agardh refers here Trapa 
(see p. 37) ; Linnseus placed Hydrocharaceae along with Palms ! in his natu- 
ral arrangement. 
Link defines his Hydrocharideae, Stratioteae, and V allisneriaceae, thus : — 
Hydrocharidece. Aquatic herbs. Leaves with parallel veins connected 
with lateral ones ; sheath separate. Calyx divided to the base. Corolla po- 
lypetalous. Pericarpium. Albumen none, unless the thickened part of the 
embryo. Hydrocharis. 
Stratiotece. Aquatic herbs. Leaves sheathing with parallel veins. Flowers 
spathaceous. Calyx tubular. Corolla polypetalous, inserted on the calyx. A 
berry. Stratiotes. 
VallisneriacecB. Aquatic herbs. Dioecious, diclinous. Males; Flowers 
in a spadix, from which they finally separate. Corolla monopetalous. Fe- 
males ; Spathe 1 -flowered. Peduncles spiral. Calyx 1 -leafed. Corolla 
polypetalous. Capsules 1 -celled, many-seeded. Seeds parietal. Vallis- 
neria. 
Geography. Natives of Europe, North America, and the East Indies. 
One species is found in Egypt (Damasonium indicum), and two Vallisnerias in 
New Holland. 
Properties. Nothing known, unless that the fruit of Euhalus is eatable, 
and its fibres capable of being woven, according to Agardh {Aph. 128). The 
Janji of Hindostan, called Vallisneria alteraifolia by Roxburgh, Hydrilla by 
Hamilton, is one of the plants used in India for supplying water mechanically 
to sugar in the process of refining it. Brewster y 1. 34. 
GENERA. 
Hydrocharis, L. Stratiotes, L. 
Limnobium, Rich. Euhalus, Rich. 
Damasonium, Schreb. Blyxa, Pet. Thou. 
Ottelia, Pers. Valisneria, L. 
Physcium, Lour. 
Anacharis, Rich. Boottia, Wall. 
Elodea, Rich. Saivala, Wall. cat. 
Udora, Nutt. 
Serpicula, Roxb 
Hydrilla, Rich. 
