382 FLOWERS OF GARDEN AND GREENHOUSE 



H. GLOBULOSA (globular). Leaves leathery, hairy, oblong. Flowers 

 creamy with pink centre, in globose umbels ; April. Introduced from 

 India, 1880. 



H. iMPERiALis (imperial). Leaves slightly woolly, 6 to 9 inches 

 long. Flowers waxy, 3 inches across, reddish brown, in large umbels ; 

 June. Introduced from Borneo, 1847. 



Cultivation. ^ warm greenhouse or stove is the best situation for 



growing Hoyas. They like a fairly humid, though not too 

 close an atmosphere, and a little shade in bright weather— but only a 

 little. A perfectly-drained peaty soil is best suited to their wants, and 

 they will do well if trained against a wall, where they will obtain more 

 moisture than against woodwork of any kind. In such a position they 

 will send out rootlets from the branches which render them independent 

 of the true roots below. In large houses they may be trained round elm 

 posts, to the bark of which their aerial roots cling and find nourishment. 

 The plants dislike much water at the roots. H. hella requires more 

 warmth than H. carnosa, and is often grafted upon a stouter species; 

 owing to its habit this species does best where it can grow down— as 

 over the trunk of a tree-fern. Hoijas are propagated by cuttings or 

 layers. Cuttings are made from the previous year's growth, and are 

 struck in sandy peat-soil under a bell-glass, on bottom heat. 



Natural Order Gentiane^. Genus Gentiana 



Gentiana (from Gentius, the name of a king of lUyricum, who is said 

 to have discovered the medicinal virtues of these plants). A genus 

 comprising about one hundred and eighty hardy species of annual or 

 perennial herbs with opposite leaves, and mostly solitary flowers. The 

 calyx is four- or five-lobed; the corolla funnel-shaped or salver-shaped 

 four- or five-lobed. Stamens, four or five, attached to the corolla-tube '; 

 ovary one-celled, with two stigmas. The species are distributed chiefly 

 throughout the Temperate and Alpine Regions of the world, and are 

 rare in the Arctic Regions. Five species occur in Britain. 



History. Gentians are mostly plants of mountainous or hilly 



districts, and every visitor to the European Alps is struck 



by the beauty of form and intensity of colour of the species commonly 



found there in profusion, surrounded by ice and snow. Though blue is 



the prevailing hue of their flowers, purple, lilac, yellow, and white are 



