ANGIOSPERM^, DICOTYLEDONES. 777 



Alliance LVI. — DisciflorsB. 



Families: Linacece, Erythroxylacece, Oxalidacece, Humiriacece, Mal/pighiacecB, Zygo- 

 phyllacece, Geraniacece, Balsaminece, Tropceolacece, Bwtacece, Aurantiacece, 

 Biosmacece, Zanthoxylacece, Simarubacece, Ochnacece, Burseracece, Meliacece, 

 Ilicinece, Celastrinece, Rhamnacece, AmpelidecB, Sapindacece, Acerinece, 

 Hippocastanece, Sabiacece, Terebinthacece. 



Annual and perennial herbs, shrubs, and trees, with simple and compound 

 foliage-leaves. Flowers actinomorphic and zygomorphic, hermaphrodite, pseudo- 

 hermaphrodite, monoecious and dicEcious; arranged in varying types of inflores- 

 cence. Floral-leaves in two 4-5-merous whorls; the lower whorl a calyx, the upper 

 a corolla. The gynseceum is composed of a whorl of carpels borne on a swollen 

 disc. Ovary superior. Each carpel has a separate loculus. In Aurantiacese and 

 Ampelideee the carpels are completely united so as to form a single pistil; in 

 Rutacese and Zygophyllacese they are united at the base and form a lobed ovary, 

 whilst in Zanthoxylacese, Ochnacese, and Simarubacese, they are quite separate (see 

 fig. 438^). In Terebinthacese only one carpel is developed, but there are usually 

 traces of suppressed carpels close to it. The ovules are in the inner angles of the 

 loculi; in Aurantiacese, Rutacese, and Zygophyllaceae their number exceeds two in 

 each loculus, in the other families it is only 1-2. The stamens are arranged in 1-2 

 whorls, and number 4-6 in each whorl; they spring from the edge or from the 

 surface of the floral receptacle, which is swollen and forms a ring round the ovary; 

 their place of origin is always lower than the base of the ovary (see figs. 438 ^' '• ^). 

 The pollen is adhesive. The fruit contains either few seeds or a single compara- 

 tively large seed. 



The Disciflorse are in most instances woody plants, containing etherial oils and 

 aromatic, resinous substances like turpentine. Amongst the Malpighiaeese, Celas- 

 trinese, and Ampelidese are many lianes. The foliage-leaves are undivided in 

 Erythroxylaceee and Celastrinese (see fig. 438 ^), lobed in most Aceracese and 

 Ampelidese, and variously segmented and compounded in the other families (see 

 fig. 438^). The petals are usually small, and of a greenish-yellow colour. The 

 filaments in Melianthaceae and Aurantiacese are connate all together, or in groups. 

 The fruits are extremely various. In Staphyleacese and Diosmacese they are 

 follicles ; in Celastracese and Rutacese, capsules (see fig. 325 ^ p. 431) ; in Zygo- 

 phyllacese, Aceracese, and Malpighiacese, schizocarps; in the Tree of Heaven, of the 

 family Simarubacese, winged achenes (samaras, see fig. 323^, p. 428); and in 

 Ampelidese and Aurantiacese, berries. The Diseiflorse are distributed over the 

 whole earth. The majority belong to the tropics, and several, e.g. Burseracese, 

 Ochnacese, and Malpighiacese are exclusively tropical. The Diosmacese are confined 

 to South Africa, the Rutacese to the districts of the Mediterranean and the Black 

 Sea. Comparatively few species occur in the Northern Temperate Zone, or in 

 corresponding situations on mountains. The Mountain Maple covers about the 



