256 MANUAL OF BOTANY 



and surrounded by an involucre of bracts, which ultimately 

 form a cupule round the ovary and fruit ; ovary inferior, sur- 

 mounted by a rudimentary calyx, 3- or more- celled; ovtdes 2 

 in each cell or solitary, pendulous or peltate ; stigmas almost 

 sessile. Fruit a glans or nut, 1-celled by abortion, more or less 

 enclosed by the cupule. Seeds large, 1 or 2, exalbuminous ; 

 cotyledons thick, fleshy or farinaceous ; radicle superior. 



Bentham and Hooker include the order Betulaceae in the 

 Cupuliferae, and divide the order as thus constituted into three 

 tribes as follows : — Tribe 1. Betuleae. Tribe 2. Coryleae. Tribe 

 3. Quercinese. ; . . 



The Betuleae are at once distinguished by their superior 

 ovary and the absence of a cupule from the two latter ; and the 

 Coryleae from the Quercineae by the male flowers being achla- 

 mydeous, and having one ovule in each cell of the ovary ; the 

 latter having a 3 — 7-lobed ovary, and 2 ovules in each cell. 



Some authors, again, divide this order into two orders — 

 Corylaceae and Cupuliferae. 



Distrihution and Numbers. — They abound in the forests of 

 temperate regions. A few occur in the high lands of tropical 

 and hot climates. Illustrative Genera : — Carpinus, Tourn. ; 

 Corylus, Tourn. ; Quercus, Tourn. There are nearly 300 

 species. 



Properties and C7ses.— Most important on account of their 

 valuable timber. Many yield edible seeds, and some have 

 highly astringent barks and cupules. 



Order 42. Betulace^, the Birch Order. — Character. — 

 Trees or shrubs. Leaves simple, alternate, with deciduous 

 stipules. Flowers small, unisexual, monoecious, amentaceous, 

 with no true calyx, but in its place small scaly bracts, which in 

 some cases are arranged in a whorled manner. Male Jiowers 

 with 2 or 3 stamens opposite the bracts. Female flowers with a 

 2-celled ovary, and 1 pendulous anatropous ovule in each cell. 

 Fruit dry, thin, indehiscent, often winged, 1— 2-celled, 1-seeded, 

 without a cupule. Seed pendulous, exalbuminous ; embryo 

 straight ; radicle superior. Bentham and HooT<er include this 

 order in Cupulifercs as the tribe Betulece. 



Distribution and Numbers. — They are principally natives of 

 the colder regions in the northern hemisphere. Illustrative 

 Genera: — Betula, Linn.; Alnus, Tourn. These are the only 

 genera ; there are about 70 species. 



Properties and Uses. — They are valuable for their timber, 

 and for their astringent, tonic, and febrifugal barks. 



