EYDROCLEYS 
427 
Hyacinthus (Tourn.) Linn. Liliaceae (v). 30 sp. Medit., Afr. Many 
forms of hyacinth (derived from H. orientalis L.) are cultivated. 
[For the wild hyacinth of Brit., see Scilla.] 
Hydnophytum Jack. Rubiaceae (11. 15). 30 sp. E. As., New Guinea, 
Fiji, &c. Epiphytes with ant-inhabited tubers, like Myrmecodia (q.v.). 
Hydnora Thunb. Hydnoraceae. 7 sp. Afr. 
Hydnoraceae. Dicotyledons (Archichl. Aristolochiales). 2 gen. with 
7 sp., Afr., S. Am. Parasites like Rafflesiaceae. See Nat. Pfl. or 
Kerner’s Nat. Hist, of Pits. 
Hydrangea Gronov. ex Linn. Saxifragaceae (hi). 20 sp. N. Hemisph. 
Shrubs with opp. leaves, some climbing. Firs, in cymose corymbs, 
the outer (or in cultivated forms all the firs.) neuter with petaloid calyx, 
giving conspicuousness to the infl. (cf. Compositae, Umbelliferae). 
Hydrangeaceae (Warming) = Saxifragaceae (suborder ill). 
Hydrastis Ellis. Ranunculaceae (1). 2 sp., 1 in Japan, 1 in N. Am. 
{H. canadensis L., golden-seal). The latter is used as a tonic &c. 
Eydrocaryaceae. Dicotyledons (Archichl. Myrtiflorae). Only genus 
Trapa (q.v.). Often placed in Onagraceae. 
Hydrocharideae (Benth.- Hooker) = Hydrocharitaceae. 
Hydrocharis Linn. Hydrocharitaceae. 1 sp. Eur. (incl. Brit.), As., 
H. Morsus-ranae L., the frog-bit, a rootless water plant with orbicular 
floating leaves. Firs, dioecious, produced upon the surface of the 
water. During summer the plant multiplies much by horizontal 
stolons, which form new plants at the ends. In autumn large buds 
are formed on the stolons and drop off to spend the winter at the 
bottom of the pond. In spring they float up and develope into new 
plants. 
Hydrocharitaceae. Monocotyledons (Helobieae). 13 gen. with about 
55 sp. trop. and temp., all water plants, some marine (Halophila, 
Enalus, Thalassia). Most have ribbon-like submerged leaves, a 
few only have floating leaves (Hydrocharis &c.); some have leaves 
projecting above the water. In the leaf- axils are ‘squamulae intra- 
vaginales ’ (cf. Potamogetonaceae). Several buds are frequently found 
in one leaf-axil. 
Sexes usually in different firs., commonly on different plants. Infl. 
axillary, usually 1 -flowered when ? , often more than 1 if S , enclosed at 
first in a spathe of two or more (1 in Hydrocharis ? ) fused leaves. Fir. 
usually regular, 3-merous. Perianth usually in two whorls, the 
outer sepaloid, the inner petaloid; sta. in 1 — 5 whorls, the innermost 
often staminodial; cpls. (2 — 15), forming an inf. ovary, i-loc. with 
parietal placentation ; ovules 00, ortho- to ana-tropous, erect to 
pendulous; stigmas as many as cpls. Fruit irregularly dehiscent, 
containing 00 exalbuminous seeds. [Placed in Microspermae by Benth.- 
Hooker.] Chief genera: Halophila, Elodea, Vallisneria, Stratiotes, 
Hydrocharis. 
Hydrocleys Rich. Butomaceae. 1 sp. Brazil, H. 7 iymphoides Buchenau 
