CORNACE.E 785 



embryo in copious fleshy albumen; cotyledons foliaceous; radicle terete, turned toward the 

 hilum. 



The widely distributed Cornel family with ten genera, more numerous in temperate than 

 in tropical regions, has arborescent representatives of the genus Cornus in North America. 



1. CORNUS L. Dogwood. 



Trees and shrubs, with astringent bark, opposite or rarely alternate deciduous leaves con- 

 duplicate or involute in the bud. Flowers small, perfect, white, greenish white or yellow; 

 calyx-tube minutely 4-toothed, the teeth valvate in the bud; disk pulvinate, depressed in 

 the centre, or obsolete; petals 4, valvate in the bud, oblong-ovate, inserted on the margin 

 of the disk; stamens 4, alternate with the petals; filaments slender, exserted; ovary 2- 

 celled; style exserted, simple, columnar, crowned w r ith a single capitate or truncate stigma; 

 raphe dorsal. Fruit ovoid or oblong; flesh thin and succulent; nut bony or crustaceous, 

 2-celled, 2 or sometimes 1-seeded. Seed compressed; embryo straight or slightly incurved. 



Cornus with nearly fifty species is widely distributed through the three continents of the 

 northern hemisphere, and south of the equator is represented in Peru by a single species. 

 Of the sixteen or seventeen species of the United States four are arborescent. Cornus is 

 rich in tannic acid, and the bark and occasionally the leaves and unripe fruit are used as 

 tonics, astringents, and febrifuges. Of exotic species, Cornus mas, L., is often planted in 

 the eastern states as an ornamental tree, and its edible fruit is used in Europe in preserves 

 and cordials. The wood of Cornus is hard, close-grained, and durable, and is used in 

 turnery and for charcoal. 



The generic name, from cornu, relates to the hardness of the wood produced by plants of 

 this genus. 



CONSPECTUS OF THE ARBORESCENT SPECIES OF THE UNITED STATES. 



Flowers greenish, in a dense cymose head surrounded by a conspicuous corolla-like invo- 

 lucre of 4-6 white or rarely red scales, from terminal buds formed the previous sum- 

 mer; fruit ovoid, bright red, rarely yellow. 



Heads of flower-buds inclosed by the involucre during the winter; involucral scales 4, 



obcordate or notched at apex; leaves ovate to elliptic. 1. C. florida (A, C). 



Heads of flower-buds inclosed only at base by the involucre during the winter; involucral 



scales 4-6, oblong to obovate, usually acute at apex; leaves ovate or rarely obovate. 



2. C. NuttalUi (B, G). 

 Flowers cream color, in a flat cymose head, without involucral scales, terminal on shoots 



of the year; fruit subglobose, white or dark blue. 



Leaves opposite, scabrous above; fruit white. 3. C. asperifolia (A, C). 



Leaves mostly alternate and clustered at the end of the branches, smooth above; fruit 



dark blue or rarely yellow. 4. C. alternifolia (A, C). 



1. Cornus florida L. Flowering Dogwood. 



Leaves ovate to elliptic dt rarely slightly obovate, acute and often contracted into a 

 slender point at apex, gradually narrowed at base, remotely and obscurely crenulate- 

 toothed on the somewhat thickened margins, and mostly clustered at the end of the 

 branches, when they unfold pale and pubescent below and puberulous above, and at ma- 

 turity thick and firm, bright green and covered with minute appressed hairs on the upper 

 surface, pale or sometimes almost white and more or less pubescent on the lower surface, 3'- 

 6' long and l|'-2' wide, with a prominent light-colored midrib deeply impressed above, and 

 5 or 6 pairs of primary veins connected by obscure reticulate veinlets; in the autumn turning 

 bright scarlet on the upper surface, remaining pale on the lower surface; petioles grooved, 

 \'~y in length. Flowers: head of flower-buds appearing during the summer between the 

 upper pair of lateral leaf-buds, inclosed by 4 involucral scales remaining light brown and 

 more or less covered with pale hairs during the winter, and borne on a stout club-shaped 

 puberulous peduncle \ f long or less during the winter and becoming I'-l^' in length; in- 



