184 Encyclopaedia of Gardening 



spring or summer. The shoots should be thinned out when they 

 become crowded. Vigorous syringing in summer will keep down 

 mealy bug. Very little water should be given in winter. We know 

 of a plant thriving for years in a sitting-room. 



Humea (hu-mea, after Lady Hume. Ord. Compositae). Humea 

 elegans is one of the most distinctive of plants, not only oh account 

 of its appearance, although that is uncommon, but because of its 

 piquant and agreeable perfume. It grows several feet high in a 

 season, and produces long plumes of red inflorescence. Two or 

 three plants will scent a large house. It is easily raised from 

 seed, which may be sown in a warm frame or greenhouse in summer, 

 the seedlings pricked off, potted singly, and repotted till they are in 

 6-in. or /-in., in which they may bloom. Loam, with a third of 

 decayed manure and some sand, makes a suitable compost. The 

 plants may be discarded after flowering. It is thus treated as a 

 biennial. 



Humulus (hu-mulus, from humus, the ground, in reference to the 

 creeping habit. Ord. Urticaceae) . This genus gives us the com- 

 mercial hop, which is used for flavouring beer. The Japanese Hop, 

 H. Japonicus, is worth planting in the garden for the pillar of a 

 pergola. It will thrive in ordinary soil, and may be increased by 

 division in spring. There is a golden-leaved variety called aureus. 



Humus. See Manure and Lime. 



Hunnemannia (hunneman-nia, after Herr Hunnemann. Ord. 

 Papaveraceae) . H. fumariaefolia is a brilliant Poppywort, with 

 yellow flowers in summer. It is a herbaceous perennial, not entirely 

 hardy, and needing a sheltered place or frame protection in winter. 

 It may be propagated by seeds sown outdoors in summer, and likes 

 light, well-drained soil. See the Botanical Magazine, t. 3061. 



Hutchinsia (hutchin-sia, after Miss Hutchins. Ord. Cruciferae). 

 The most popular species of this small genus is alpina, a pretty 

 little plant for the rockery, clinging closely to the stones and cover- 

 ing itself with white flowers in spring. It likes a sandy compost, 

 and thrives in limestone. Propagation is by seed in spring. 



Hyacinth. See Bulbs. 



Hyacinthus (see also Bulbs). H. amethystinus is the Spanish 

 Hyacinth (see the Botanical Magazine, t. 2425); H. orientalis is the 

 common Hyacinth (Bot. Mag., t. 937). The variety of orientalis 

 called albulus is the white Roman Hyacinth. H. candicans is also 

 called Galtonia candicans. It is a good plant for the herbaceous 

 border. 



Hybrid, Hybridisation. A hybrid is a cross between two species. 

 In rare cases (e.g., amongst a few kinds of Orchids) g;enera have 

 been crossed, and the offspring are called bigeneric hybrids. When 

 hybrids are crossed between themselves the offspring are called 

 varieties. When species are crossed the work is described as 

 hybridisation; when varieties are crossed it is spoken of as cross- 

 fertilisation. In both cases it consists in taking pollen from the 

 anthers of one flower and placing it on the stigma of another. This 



