CHAP. XXX. 



XANTHOXYLA CE^. 



487 



App. i. Half-hardy Species qfRiita. 



The following species of Rhta. are generally kept in the frame or green-house ; but there is little 

 doubt that they would live in very dry soil or in lime rubbish, at the base of a wall, with some pro- 

 tection during severe weather. R. pinnata L. {Bot. Reg., t. 307.), a native of the Canary Islands, 

 where it grows to the height of 6 ft. ; R. bractebsa Dec, a shrub 2 ft. high, a native of Sicily ; R. 

 angustifolia Pcrs. {fig. 156.), a native of the south of France, which was 

 considered by Linna?us and others as a variety of the common rue; 

 R. macrophylla Sol., from the north of Africa, where it grows 3 ft. 

 high ; R. montana Clus., from the south of Europe, also growing 3 ft. 

 high ; R. divaricata Tenore, from the south of Italy; R. Corsica Dec, 156 

 from Corsica; R. albiflora Hook., from Nepal, which was introduced 

 in 1823, and which is found in the Himalayas, at elevations of from 

 500 ft. to 800 ft. ; together with some other species from Nepal, from the 

 south of Europe, and from the north of Africa; might all, we think, be 

 tried at the base of a conservative wall, with every prospect of success. 

 Perhaps half or more of the sorts above enumerated are only varieties 

 of .ftuta graveolens, but the shrub is so truly beautiful in the form and 

 colour of its foliage, in its neat and compact shape, and its numerous 

 flowers, that every variety is well worth cultivating. 



Genus II. 



APLOPHY'LLUM Andr. Juss. The Aplophyllum, or 

 Rue. Lin. Si/st. Decandria Monogynia. 



This genus, which forms a section of Rhta in De Candolle's Prodromus, 

 was instituted by A. Jussieu in Mem. Mus., 12. p. 464., and is adopted by G. 

 Don. It contains two or three species of small undershrubs, which are 

 hardy, but which are more frequently treated as herbaceous than as ligneous 

 plants. 



it- 1. A. Unifblium G. Don., .Suta /inifblia L., (Bot. Rep., 565., and our 

 fig. 157.) has entire oblong-lanceolate leaves, and yellow flowers in corymbs. 

 It is a native of Spain, near Valencia, and also of Greece. It was introduced 

 in 1752, grows to about 1 ft. in height, and flowers from July to September. 



«. 2. A. suaveolens G. Don., i?uta suaveolens Dec, has spathulately lance- 

 olate glaucous leaves, and yellow flowers in corymbs, smelling like those of 

 Primula officinalis. It is a native of Tauria, where it forms a shrub about 

 2 ft. high ; and was introduced in 1800. It flowers from June to September. 



n. 3. A. fruticulbsum G. Don, i^uta fruticulbsa Lab., is a native of the 

 country about Damascus. It grows about 1 ft high, but has not yet been in- 

 troduced into Britain. 



Simple-leaved 

 157 



CHAP. XXX. 



OF THE HARDY AND HALF-HARDY LIGNEOUS PLANTS OF THE 

 ORDER XANTHOXYLA^CE^E. 



The genera belonging to this order which contain hardy species are three, 

 Xanthoxylum, Ptelea, and Aildntus, which are thus distinguished in Don's 

 Mill, i. p. 777. 



Xantho'xylum L.> and H. et Kth. Flowers bisexual. Calyx 3 — 5-parted, 

 with an equal number of petals and stamens. Carpels 1 — 5, 2-valved. 

 Leaves simple, ternate, abruptly and impari-pinnate. 



JPte v lea L. Flowers bisexual. Calyx 4 — 5-parted. Petals 4 — 5. Sta- 

 mens 4 — 5. Fruit compressed, 2 — 3-celled ; cells 1-seeded, turgid in the 

 centre, each cell extended into an orbicular reticulated wing. Leaves of 3 

 leaflets, rarely of 5 leaflets. 



Aila'ntus Desf. Flowers polygamous. Calyx 5-cleft. Petals 5. Stamens 

 10, unequal. Styles 3 — 5, arising from the notches of the ovaries. Carpels 

 3 — 5, membraneous, 1-celled, 1-seeded. Leaves abruptly or impari- 

 pinnate. 



