KEY, BASED UPON FLOWERS. 31 



oblong, ovate, acuminate and not very unequal at the base; 



anthers extrorse. . 11. U. FULVA. 



gg. Fruit a drupe; leaves long taper-pointed; anthers introrse. 



12. CELTIS OCCIDENTALIS. 



CC. Flowers diclinous, and one or both sorts in catkins. 

 d. Only one sort (the staminate flowers), in catkins. 



e. Fertile flowers, single or clustered, and fruit naked; leaves pinnately 

 compound (Juglandacece); calyx and corolla both present in the 

 fertile flowers and 4 parted; fruit a try ma (Juglans), which is 



ovate-oblong and viscid-hairy 14. J. CINEREA. 



ee. Fertile flowers 1-3 together, invested wholly or partly with a many- 

 scaled involucre; leaves simple. 



f. Involucre valveless, cup-like and only partly inclosing the one nut, i. e., 

 acorn (Quercus), leaves smooth, thin, lobed with bristle-pointed 

 lobes; acorns maturing the second year, and with involucral cup 

 very shallow and composed of fine, closely appressed scales. 



15. Q. RUBRA. 

 ff. Involucre 4-valved and inclosing two three-cornered nuts. 



16. FAGUS FERRUGINEA. 

 dd. Both staminate and pistilate flowers in catkins. 



e. Ovary 1-celled and many-seeded; the seeds at maturity furnished with a 

 hairy tuft (Salicacece); bracts of catkins lacerately fringed, calyx 

 a disk-like cup; stamens 8-30; leaves broad (Populus); branchlets 

 terete; leaves ovate-orbicular, acute and with large irregular 



teeth 18. P. GRANDIDENTATA. 



ee. Ovary 1-2-celled with a single ovule in each cell; calyx scale-like or 

 none; stigmas 2, filamentous; fertile flowers arranged 2 or 3 

 under each scale of the cone-like catkin (Betula); bark of trunk 

 yellowish or grayish, peeling off in thin strips; fertile catkins 



short, erect 17. B. LUTEA. 



aa. Gymnospermae seeds naked, borne superficially on carpellary scales. Cone- 

 bearing (Coniferce). 

 b. Scales of cone many, each in the axil of a bract and bearing 2 inverted ovules; 



seeds winged. 



C. Leaves evergreen, fascicled; cones maturing the second year (Pinus), about 

 half as long as the leaves, and with scales thickened at the apex 



but unarmed; leaves arranged in twos 19. P. RESINOSA. 



CC. Leaves evergreen, scattered (not fascicled); cones with thin scales, maturing 



the first year (Abies}. 

 d. Cones erect, cylindrical, large 3-4 in., and with conspicuous bracts; leaves 



flat, linear 22. A. BALSAMEA. 



dd. Cones pendent and bracts inconspicuous. 



e. Small, 8 lines or less, scales entire at tip; leaves linear. 



21. A. CANADENSIS. 



ee. Larger, 1-1 \ in., scales eroded at tip; leaves 4-angled 20. A. NIGRA. 



ccc. Leaves deciduous, soft, needle-shaped and in fascicles of many each; cones 

 about 8 lines in length, scales thin (Larix) and with inflected 



margins 23. L. AMERICANA. 



bb. Scales of cone few, without bracts and each bearing 2-8 erect ovules. 



C. Flowers monoecious; scales of the oblong cone dry and divergent at maturity; 



leaves evergreen THUJA OCCIDENTALS. 



CC. Flowers dioscious; scales fleshy and consolidated, making a small, dark blue, 

 berry-like fruit; leaves scale-like and imbricated in 4 rows. 



25. JUNIPERUS VlRGINIANA. 



