92 SALICACE^E. Populus. 



H +- Stamens 60 or more: leaves deltoid, sinuately crenate : petioles flattened : 

 seeds 1| or 2 lines lony: young bark yellowish, becoming lujht gray. 



3. P. Fremonti, Watson. A large tree, with gray cracked bark and terete 

 branches : leaves broadly deltoid or often somewhat reniform, with a broad acute 

 apex and usually more or less of a sinus at base, few serratures (4 to 12 on each 

 side), and petioles 1 to 2| inches long ; the petioles, branchlets, and margins of the 

 leaves often with short spreading pubescence when young : aments with glabrous 

 rhachis and bracts; the staminate loose, with pedicels 8 to 10 lines long and con- 

 spicuous disks 3 or 4 lines broad : styles 3 : fruiting aments 3 or 4 inches long : 

 capsules ovate, 3 or 4 lines long, on short stout pedicels (a line or two long), the 

 disk 3 lines broad ; valves 3, thick-coriaceous : seeds white. Proc. Am. Acad. x. 

 350 and 1. c. 136. P. monilifera, Newberry, Pacif. R. Rep. vi. 89; Watson, Bot. 

 King Exped. 327. 



Var. ("?) Wislizeni, Watson, 1. c. 137. Leaves sharply acuminate, truncate or 

 slightly cuneate at base : staminate aruents with shorter pedicels and less dilated 

 thin disks : pistillate aments very slender, 2 to 6 inches long : disk 2 or 3 lines broad : 

 capsules ovate to ovate-oblong, somewhat angled, 3- or usually 4-valved, 4 or 5 lines 

 long, on slender pedicels 2 to 8 lines long. P. monilifera, Torrey, Bot. Mex. Bound. 

 204, etc. 



The typical form of the species is found on the Upper Sacramento River and eastward in Nevada 

 and to S. Utah (Palmar, Parry) ; the variety is the prevalent Cottonwood in the more southern 

 districts, ranging from San Diego County (Jaraul Valley, Palmer) and the Colorado Valley (Ft. 

 Yuma, Sclwtt) to S. Utah and the Rio Grande. 



ORDER XCIV. JUGLANDACE.aS. 



Monoecious trees or shrubs, with alternate pinnate leaves without stipules, sterile 

 flowers in aments with usually numerous stamens and a 3 - G-lobed perianth adnate 

 to a bract, fertile flowers solitary or few and spicate, with a 2 - 5-lobed (sometimes 

 double) perianth more or less adherent to the 1-ovuled 1-celled (at length imper- 

 fectly 2 - 4-celled) ovary, and a fleshy indehiscent or 4-valved fruit containing a 

 bony nut and a large exalbuminous 2 - 4-lobed orthotropous seed. Stamens with 

 very short filaments and the connective usually prolonged. Style short ; stigmas 

 2 - 4-lobed. Embryo fleshy and oily, covered by a membranous testa ; radicle very 

 short, superior. 



The principal genera are Juglans and Carya, almost wholly North American, the latter includ- 

 ing the Hickory and Pecan Nuts of the Atlantic States. Three other small genera are Asiatic. 

 The total number of species is 25 or 30. 



1. JUGLANS, Linn. WALNUT. 



Staminate aments from the previous year's wood, long, solitary or in pairs ; peri- 

 anth unequally 3 - 6-lobed ; stamens 1 2 to 40. Fertile flowers solitary, or few in 

 a short terminal spike, the calyx adherent to the ovary, 4-toothed and with 4 small 

 petals. Style short ; stigmas 2, linear or clavate, fringed. Pericarp fleshy, indehis- 

 cent, enclosing an irregularly rugose nut, 2-valved in germination. Trees or large 

 shrubs, with somewhat resinous-aromatic bark and foliage, nearly naked buds, and 

 unequally pinnate leaves of many serrate leaflets ; pith in plates. 



Including the Black Walnut (J. nigra), very valuable and extensively used for cabinet pur- 



