856 LXX. HIPPOCASTANE^E. 



fleshy. EMBEYO exalbumiuous ; cotyledons foliaceous, green, accumbent, irregularly 

 folded or convolute ; radicle descending, facing the hilum. 



GENERA. 

 Acer. Xeguudo. Dobinea. .- 



Acerineee, regarded by Benthani and Hooker fil. as a sub-order of Sapindaceee (see p. 353), only differ 

 from these in their always opposite leaves and non-appendiculate petals, and in their occasionally trimerous 

 fruit (Acerp&eudo-Platttnus), as in most Sapindaceee. Hippocastaneee only differ from Acerineee in their capsule 

 with semi-septiferous valves ; and are further allied, since in both orders the buds bear both leaves and 

 flowers. For the affinity with Malpiyhiaceee see p. 301. 



Acerineee inhabit northern temperate regions, and especially Japan, the Himalayas, and eastern North 

 America. The curious genus Dobinea, which is placed in Acerineee, is Himalayan ; [it has apetalous ? 

 flowers without a disk, and a one-celled ovary, which ripens into a small broadly-winged achene. ED.]. 



Acerineee contain a sugary sap, milky in some, limpid in others, which is obtained by incision of the 

 trunk, and is cither evaporated for sugar (the Maple Sugar of Canada), or allowed to ferment and thus 

 form spirituous or acid liquors. Their bark is astringent, and yields reddish or yellow colouring principles. 

 [The wood of various species is of great value, especially the Bird's-eye Maple of America. ED.] 



LXX. HIPPOCASTANE^E, 1 Endlicher. 



Large or small TREES with scaly buds. LEAVES opposite [alternate in 

 Ungnadia. ED.], generally digitate, rarely imparipinnate, with toothed or crenate 

 leaflets ; stipules 0. FLOWERS $f or polygamous, in racemes or terminal thyrsi. 

 CALYX campanulate or tubular, 5-fid, lobes unequal, imbricate. PETALS 4-5, 

 inserted on the receptacle, unequal, clawed, not appendiculate, imbricate. DISK 

 hypogynous, entire, annular or unilateral. STAMENS 5 8, usually 7, inserted within 

 the disk, and free ; filaments filiform, exserted, ascending ; anthers 2-celled, dehiscence 

 longitudinal. OVARY sessile, oblong or lanceolate, of 3 2-ovuled cells ; style conical 

 or filiform ; stigma pointed ; ovules curved, fixed to the central angle of the cell, 

 superimposed or horizontal, or one ascending, the other pendulous. CAPSULE coria- 

 ceous, naked or spinous, 3-celled or 2-1 -celled by suppression, loculicidal, valves 

 semi-septiferous. SEEDS usually solitary in each cell; testa coriaceous, shining; 

 hilum basilar, large. EMBRYO exalbuminous, curved ; cotyledons large, thick, fleshy, 

 often more or less confluent; radicle short, near the hilum. 



PRINCIPAL GENERA. 

 ^Esculus. Pavia. Ungnadia. 



The little group of Hippocastaneee, which evidently belongs to the family of Sapindaceee, is only dis- 

 tinguished from the latter by its opposite digitate leaves and the 2-ovuled ovarian cells; and it must 

 further be observed that the genus Ungnadia, placed by botanists near jEsadux, has alternate and impari- 

 pinnate leaves, which bring it still nearer to Sapindaceee. For the affinity with Acerineee, see this family. 



Hippocastaneee are chiefly North American, except Castanella [which is not referable to Hippocastaneee, 



1 Included in the ' Genera Plantarum ' in Sapindacea, nadia being alternate invalidates the only character 

 where it does not even form a tribe ; the leaves of Vug- distinguishing it from Sapindaceee proper. En. 



