412 
HIPPOMANE 
Hippomane Linn. Euphorbiaceae (A. II. 7). 1 sp. Cent. Am., W. Ind., 
Columbia (the manchineel). The latex is highly poisonous. 
Hippophae Linn. Elaeagnaceae. 2 sp., one Himal., the other, H '. 
rhamnoides L., the sea buckthorn, from Brit, to Altai Mts. In the 
$ fir. the bracteoles form a hood over the sta. in wet weather; when 
the air is drier, they separate at the sides, and the pollen may be 
blown away by wind. 
Hippuris Linn. Haloragidaceae. 1 sp., H. vulgaris L. the mare’s-tail, 
Eur. (incl. Brit.), As., Austr., Am. A water plant, with creeping 
rhizome and erect shoots, whose upper parts usually project above the 
water. Leaves linear, in whorls, the submerged ones longer and 
more flaccid than the aerial. Fir. sessile in axil of leaf, $ (or some- 
times ? on some stocks; cf. Labiatae), consisting of 1 epigynous sta. 
and 1 cpl., with a slight seam representing the calyx ; wind fertilised. 
Hiraea Jacq. (Mascagnia Bert.). Malpighiaceae (1). 40 sp. trop. Am. 
Hirtella Linn. Rosaceae (vi. 13). 40 sp. S. and Cent. Am., 1 Madag. 
Fir. zygomorphic. The axis is deeply hollowed on one side, but the 
sta. and cpl. are not in the hollow, but on the other side of the surface 
of the axis. 
Hodgsonia Hook. f. et Thoms. Cucurbitaceae (ill). 1 sp. Indo-mal. 
Hoffmannia Sw. Rubiaceae (1. 8). 20 sp. trop. Am. 
Holboellia Wall. Lardizabalaceae. 2 sp. Himal. 
Holcus Linn. Gramineae (ix). 8 sp. Eur., N. and S. Afr. 2 in Brit., 
H. mollis L., and H \ lanatus L., Yorkshire fog or soft-grass, a 
common weed. 
Holosteum Dill, ex Linn. Caryophyllaceae (n. 1). 6 sp. N. temp. 
(1 Brit.). 
Homalium Jacq. Flacourtiaceae. 35 sp. trop. After fertilisation the 
sepals or petals, or both, grow large and form wings (often hairy) to 
the fruit. (Samydaceae Benth. -Hooker.) 
Homalomena Schott. Araceae (v). 20 sp. trop. As. and S. Am. 
Homogyne Cass. Compositae (vm). 3 sp. Mts. of Eur. 
Honckenya Ehrh. = Arenaria Rupp, (same spec. name). 
Hordeum (Tourn.) Linn. Gramineae (xu). 16 sp. temp. Eur., As., 
N. Afr., Am. 4 in Brit, (barley-grass). The spikelets are arranged 
in groups of 3 on the main axis, forming a dense spike. Each is 
1 -flowered when perfect, but commonly either the central or the two 
lateral firs, are aborted. Glumes awned. The cultivated barley is H. 
vulgare L. (P. sativum Pers.). The most common form is the var. 
distichufn or 2-rowed barley, where the central flr. of each group is 
fertile, but 6-rowed barley (var. hexastichum), and 4-rowed barley or 
bere, are also grown. The last is the most hardy and is cultivated 
as far as 70° N. (in Norway). 
Horminum (Tourn.) Linn. Labiatae (vi. 9). 1 sp. Mts. of S. Eur. 
Hosackia Dougl. Leguminosae (in. 4). 30 sp. west N. Am. 
Hosta Tratt. =Funkia Spreng. 
