﻿354 The Neiv York Slate College of Forestry 



WALNUT FAMILY. JUGLANDACEAE 

 The walnut famil}^ consists of aromatic trees with watery juice, 

 alternate, estipulate, odd-pinnately compound, deciduous leaves, 

 monoecious flowers, and a fruit which is a nut. They are chiefly 

 confined to the warmer parts of the north temperate zone. Two 

 genera occur in North America, each of which is represented in 

 New York State. 



Leaves alternate, deciduous, odd-piuuate, estipulate, with long, grooved 

 petioles; leaflets sessile or subsessile aside from the terminal, arranged in 

 pairs along the rachis. Flowers monoecious, appearing after the leaves ; 

 staminate flowers in elongated drooping aments on the growth of the previous 

 season or at the base of the growth of the season, each flower in the axil of 

 a bract; calyx 3-6 lobed adnate to the subtending bract; pistillate flowers 

 :in terminal spikes or terminal and solitary, generally subtended by a bract 

 and 2 bracteoles; calyx 3-5 lobed, adnate to the ovary; pistil consisting of a 

 1-celled or incompletely 3-4 celled, 1-ovuled ovary terminated by a short 

 style and 2 plumose stigmas. Fruit a bony nut, indehiseent or dehiscent vnth a 

 4-valved exocarp; seed large, solitary, 2-lobed, oily, exalbuminous ; cotyledons 

 fleshy. 



KEY TO THE GENERA page 



1. Staminate aments simple, sessile or short stalked; husk of the nut indehiseent; 



pith diaphragmed Juglans 354 



1. Staminate aments branched, long stalked; husk of the nut 4-valved; pith 



homogeneous Carya 355 



THE WALNUTS AND BUTTERNUTS. C4enus JUGLANS L. 

 Trees Avith spreading crowns, stout branches, superposed buds, 

 diaphragmed pith, and alternate, odd-pinnate leaves with sessile 

 or nearly sessile leaflets. About ten species are known, four of 

 which occur in the United States, two in the eastern states, one 

 in the Pacific Coast region and one in the southwest. 



Leaves alternate, odd-pinnately compound, consisting of 11-17 sessile or 

 nearly sessile leaflets; leaflets oblong-lanceolate, acute at the apex, inequi- 

 lateral at the base, finely serrate except at the base, an-anged aside from the 

 terminal in i)airs along a stout pubescent petiole. Flowers monoecious, vernal_ 

 staminate flowers in drooping, cylindric aments 3-6 inches long borne on the 

 twigs of the previous season; perianth 3-6 lobed; stamens 8-40 in 2 or more 

 series; pistillate flowers in few-flowered spikes terminating the growth of 

 the season; periajith adnate to the ovary, 4-lobed; petals 4, small, adnate to 

 the ovary at the sinuses; pistil consisting of a usually 2-eelled ovary, a short 

 style and 2 plumose stigmas. Fruit a globose or ovoid nut with fibrous, 

 somewhat fleshy, indehiseent exocarp and thick-walled, bony, rugose or sculp- 

 tured, indehiseent endocarp; seed exalbuminous, deeply lobed, oily, edible. 



KEY TO THE SPECIES page 



1. Leaflets 15-23; fruit subglobose, not viscid J. nigra 143 



1 . Leaflets 11-17; fruit ovoid and pointed, viscid I. cinerea 141 



