164 



THE DICTIONARY OF GARDENING, 



Hydrolea continued. 



H. caroliniana (Carolina), fl. blue, one to five together, axil- 

 lary, almost sessile. Summer. .. lanceolate, very acute, lin. to 

 3in. long. h. 1ft. to 2ft. North Carolina, 1824. SYN. H. quadri- 

 valvis. 



H. corymbosa (corymbose), fl. blue, in a terminal corymbose 

 cyme; sepals linear-lanceolate, villous-hispid. Summer. .. 

 lanceolate, nearly sessile, glabrous, h. 1ft. to 2ft. South 

 Carolina to Florida. 



H. quadrivalvis (four-valved). A synonym of H. caroliniana. 

 H. spinosa (thorny), fl. pale blue, terminal, corymbose. June 

 and July. .. lanceolate, h. 1ft. South America, 1791. See 

 Fig. 251 (B. R. 566.) 



HYDRO LEJE. A tribe of Hydrophyllacece. 

 HYDROMESTUS. Now included under Aphelandra. 

 HYDROPELTIS (from hydros, water, and pelte, a 

 buckler ; the plant grows in water, and has leaves in the 

 form of a buckler). OBD. Nymphceacece. A very pretty 

 little hardy aquatic plant, which should be grown in a 

 pond or a cistern of water. Increased by offsets. 

 H. purpurea (purple), fl. purple, closing and lying down on the 

 surface of the water at night ; peduncles axillary, one-flowered. 

 Summer. I. alternate, on long petioles, oval, peltate, entire, 

 floating. North America, 1798. The correct name of this plant 

 is Brasenia peltata. (B. M. 1147.) 



HYDROPHYLLACEJE. A small order of annual 

 or perennial herbs, rarely suffrutescent, natives, for the 

 most part, of North-west America. Flowers chiefly blue or 

 white, in one-sided cymes or racemes, which are mostly 

 bractless and coiled from the apex when young, as in 

 the Borage family. Leaves usually alternate, entire, 

 dentate, or pinnate, hispid. There are sixteen genera and 

 150 species. Illustrative genera are : Emmenanthe, Hy- 

 drolea, Hydrophyllum, Nemophila, Phacelia. 



H YDROFH YLLTJM (from hydor, water, and phyllon, 

 a leaf ; leaves loaded with water in spring time). OKD. 

 Hydrophyllacece. This genus comprises about six species 

 of erect or diffuse hardy perennial herbs, natives of North 

 America. Flowers white or pale blue, in cymose clusters; 

 corolla bell-shaped, five-cleft. Leaves ample. The species 

 thrive in any ordinary border, in somewhat damp soil. 

 Propagated by divisions, or by seeds. 



H. appendiculatum (appendiculate). fl. blue; cymes rather 

 loosely-flowered. June and July. 1., stem ones palmately flye- 

 lobed, rounded, the lobes toothed and pointed ; the lowest pin- 

 nately divided, h. 9in. 1812. 



H. canadense (Canadian), fl. nearly white, crowded, on very 

 short pedicels ; calyx lobes linear-awl-shaped, nearly smooth. 

 June to August. I. palmately five to seven-lobed, rounded, heart- 

 shaped at the base, unequally toothed, h. 1ft. 1759. (B. R. 



H. virginicum (Virginian), fl. blue ; calyx lobes narrowly-linear, 

 bristly-ciliate. June to August. .. pinnately divided; divisions 

 five to seven, ovate-lanceolate or oblong, pointed, sharply cut- 

 toothed, the lowest mostly two-parted, the uppermost confluent. 

 h. 1ft. to 2ft. 1739. (B. R. 331.) 



HYDROTJENIA. A synonym of Tigridia (which see). 



HYEMALIS. Of or belonging to winter. The term 

 is usually applied to plants which flower in winter. 



HYGROMETER. For horticultural purposes, the 

 best instrument for ascertaining the degree of humidity 

 in the air is the Dry and Wet Bulb Thermometer. This 

 consists simply of a couple of fine tubes, carefully 

 graduated, containing mercury. The bulb of the one 

 should be covered with thin muslin ; and round the neck, 

 and over the muslin, should be twisted loosely, or tied 

 in a loose knot, a conducting thread of lamp wick or 

 some similar material : this must pass into a vessel of water, 

 about Sin. from the bulb, and a little on one side, so 

 that evaporation may not affect the reading of the dry 

 bulb by its too near vicinity. The Hygrometer just 

 described is less complicated and expensive than those 

 in which the dew-point is ascertained by the use of 

 ether, &c. ; and, moreover, it allows of continuous obser- 

 vations. Hygrometrical tables, adapted to the use of 

 the Dry and Wet Bulb Thermometer, have been compiled 

 by James Glaisher, F.B.S., and published in pamphlet 

 form. 



HYGROMETRICAL. Indicating the approach of 

 moisture. 



HYMEN2EA (from Hymen, the god of marriage ; 

 referring to the twin leaflets). Locust-tree. OKD. 

 Leguminosoe. A genus comprising eight species of orna- 

 mental stove evergreen trees, natives of tropical America. 

 Flowers white, large or medium. Leaves bifoliolate ; 

 leaflets coriaceous. Hymena_as will thrive in a compost of 

 peat and rich loam. Firm cuttings will root, during spring, 

 in sand, in bottom heat. The only species yet cultivated 

 is the one here described. 



H. Courbaril (Courbaril). Anime Resin. /. yellow, striped 

 with purple. I. oblong-ovate, unequal-sided, and unequal at the 

 base, ending in a long acumen, h. 40ft. to 60ft. South America, 

 1688. This tree furnishes a valuable resin, and its timber is of a 

 fine brown colour, hard, and cloae-grained ; it is used for building 

 and other purposes in its native country. 



HYMENANDRA (from hymen, a membrane, and 

 aner, andros, a man ; the anthers are connected by a 

 membrane). OKD. Myrsineoe. A monotypic genus, the 

 species being a stout evergreen shrub, often cultivated 

 in stoves for the sake of its handsome foliage. For 

 culture, see Ardisia (to which the genus is allied). 



H. Wallichii (Wallich's). fl. pink, disposed in compound lateral 

 umbels ; corollas wheel-shaped, five-parted. I. large, leathery, 

 glossy, dentate, pellucid-dotted, h. 2ft. to 4ft. Western Bengal 

 and Assam. 



HYMENANTHERA (from hymen, a membrane, and 

 anther ; anthers terminated by a membrane). SYN. Solen- 

 antha. OKD. Violariew. A genus comprising about four 

 species of greenhouse or half-hardy evergreen rigid shrubs 

 or small trees, natives of Australia and New Zealand. 

 Flowers small, axillary, frequently polygamous. Leaves 

 alternate, often clustered, small, entire or toothed, without 

 stipules. The species thrive in two parts sandy peat, 

 and one of fibry loam. Young cuttings root readily in 

 sand, under a bell glass. 



H. crass-folia (thick-leaved), fl. yellowish, small; pedicels 

 solitary, axillary. Berries white, iin. long, oblong-obtuse, very 

 ornamental. I. alternate or tufted, linear-spathulate, entire. 

 h. 2ft. to 4ft. New Zealand, 1875. Hardy in the South of 

 England. (G. C. n. s., iii. 237.) 



H. dentata (toothed). /. yellow, small, axillary ; peduncles soli- 

 tary, one-flowered. April. I. from oblong-elliptical to linear, 

 obtuse or acute, coriaceous, sessile or narrowed into a short 

 petiole, h. 6ft. New South Wales, 1824. (B. M. 3163.) 



HYMENOCALLIS (from hymen, a membrane, and 

 kallos, beauty ; referring to the membranous cup in- 

 side the flower). Including Choretis and Ismene. OKD. 

 Amaryllidece. A genus containing about a score species 

 of stove or greenhouse bulbous-rooted plants, from North 

 and South America and the West Indies. Flowers white, 

 in umbels, very fragrant ; perianth tube straight, elon- 

 gated, scarcely widened at the throat. Leaves usually 

 persistent, lorate. Many species usually classed in gar- 

 dens under this genus are Pancratiums. The stove 

 species require a strong, loamy Boil, well drained, 

 and a liberal allowance of pot-room. The bulbs should 

 be buried just below the surface of the soil, and they 

 must always be kept moist, more especially during 

 the summer. The best of the stove kinds is if. macro- 

 stephana, which is as useful and beautiful as the 

 Eucharis. The greenhouse species thrive under the 

 above treatment, except that during their resting period 

 (winter) they should be kept dry. A few kinds, which 

 are known in gardens as Ismenes, may be grown in 

 the open border, if sheltered from cold winds, and 

 well drained ; but it is only in very favoured situations, 

 in England, that these plants prove satisfactory when 

 grown altogether out of doors. They may, however, 

 be planted out during the summer, and be taken up, 

 and placed in sand, in a shed or frame, for the winter. 



H. adnata (adhering -leaved). /. white, with narrow perianth 

 segments, and a deep wavy corona ; disposed in umbels. May. 

 I. rather broad, h. 1ft. South America, 1758. The variety 

 litttiralix is a handsome greenhouse plant, with pure white flowers 



