670 ARBORETUM AND FRUTICETUM. PART III. 



probably be their ultimate height, or whether they can be kept within bounds 

 bv pruning, without injury or total prevention of flowering. This point re- 

 quires consideration, or the plants are likely to become nuisances. 



Omphalobium, Yirgilitf, Sophora, several Psoralea? and 6'ytisi, form a distinct 

 stem : Schotta, Indigofera, Psoralea, Jspalathus, Podalyria, Liparia, and 

 Borbonm, as well as Cyclopia, Sarcophyllum, and Rafm'a, form branching 

 shrubs from the collar. In the three last-mentioned genera, this habit should 

 be encouraged as much as possible, by cutting them down to the ground ; 

 which occasions the larger growth of the collar: and, in old plants, the ap- 

 pearance of nakedness would be but temporary; while the quick growth of 

 numerous shoots would soon form them into dense bushes, and stronger and 

 more characteristic masses of flowers. Omphalobium and Schotia are of slow 

 growth : planting them under the shade of others will draw them up to a re- 

 quisite height without injury. 



Mr. Bowie gives the following list of the average height which several 

 species attain in their native habitations, as a guide to the cultivator in 

 planting : — 



Ft In. Ft. In. 



Virgilia intrusa and capensis 25 Indigofera cytisoides - 8 



If Virgil/a is deeply in- Podalyria styracifolia 9 



jured in the old wood, ^spalathus - 6 in. to 4 



a gum exudes, which is Rafma (annual growth) 2 ft. to 3 



used as gum Arabic. Sarcophyllum (annual growth) 1 6 



Omphalobium - - 12 Liparia sphse'rica - 3 



Sophora sylvatica - - 16 Acacia capensis, or nilotica 20 



Psoralea pinnata - - 15 Jcacia cafra - - - 12 



Cyclopia - 4 ft. to 10 



The latter thrives best by being cut down, and confined as a shrub to 6 ft. 

 They both yield the gum Arabic. 



Erythrina cafra attains the height of 60 ft., but flowers at the height of 

 15 ft. Erythrina nana, introduced by Mr. Bowie into England in 1823, 

 flowers at 2 ft. ; and may be considered as half-shrubby, as it scarcely ever 

 attains a permanent stem : it is a desirable plant. 



A portable house, for the protection of half-hardy Leguminaceae during win- 

 ter, may be made in various forms, at very little expense. Two parallel walls, 

 6 ft. or 8 ft. high, and 15 ft. or 20 ft. apart, in the direction of north and south, 

 will leave a space between, which may be covered every autumn with tem- 

 porary rafters, on which may be placed the sashes of hot-beds not in use, alter- 

 nating with boards. If moisture has been withdrawn from the soil, by drain- 

 age, and by covering with boards or with glass, or even by thatching the soil 

 during heavy rains in autumn, so as to facilitate the ripening of the wood, 

 there will be no difficulty in keeping the plants alive ; and when they are cut 

 in, in spring, they will push vigorously, and soon have a clothed appearance. 



CHAP. XLII. 



OF THE LIGNEOUS PLANTS BELONGING TO THE ORDER 7?OSA v CEiE. 



The term Rosacea has been applied to this order, because all the species 

 belonging to it agree more or less with the genus Tfosa, in essential charac- 

 ters. It includes many genera belonging to the Linnacan class Icosondria. 



Distinctive Characteristics. Flowers regular. Calyx, in most cases, with 

 5 lobes, the odd one posterior to the axis of inflorescence. Petals and 

 stamens arising from the calyx. Stamens, for the most part, numerous. 



