10 KEY, BASED UPON FRUIT. 



e 2 . Small, ovoid-lanceolate pods arranged in catkins, opening by two valves and 



containing numerous seeds furnished with silky down; leaves 

 d. Orbicular-ovate; petioles flattened. 



Dentate 18. POPULOUS GRANDIDENTATA. 



Finely serrate 72. P. TREMULOIDES. 



d*. Ovate, closely serrate, whitish and reticulate-veined beneath. 



47. P. BALSAMIFERA. 



d?. Deltoid-ovate 48 P. MONILIFERA. 



d 4 . Broadly deltoid 73. P. DILATATA. 



d b . Linear-lanceolate, tomentose on midrib above and petiole. 



45. SALIX NIGRA. 

 d 6 . Lanceolate or elliptic-lanceolate, smooth above; capsules 



Sessile or nearly so 46. SALIX ALBA var. VITELLINA. 



With slender pedicels 71. S. AMYGDALOIDES. 



a 2 . Aggregated Fruit - composed of many carpels, either closed or open and co- 

 hering or closely massed together, forming a 

 ft. Cone. 



. Scales of the cone open carpels (Coniferce). 



d. Scales many, persistent and spreading at maturity, each subtended by a 



bract; ovules 2, inverted. 

 e. Maturing the year after flowering (Pitms). 



f. Cones oblong-ovoid, scarcely 2 in. long; scales armed with a weak de- 

 ciduous prickle 75. PINUS MITIS. 



/ 2 . ones ovoid pyramidal, about 2 inches long, carpellary scales thickened 

 at the apex and 



Smooth (unarmed) 19. PINUS RESINOSA. 



Armed with a recurved prickle 50. P. RIGIDA. 



/ 3 . Cylindric, 4-6 in. long, scales thin and unarmed. ... 49. P. STROBUS. 

 e 2 . Maturing the first season the autumn after blossoming. 

 f. Ovoid or oblong, ^ in. long, pendent; bracts inconspicuous; scales per- 

 sistent on the axis, thin and with eroded tip 20. ABIES NIGRA. 



/ 2 . Ovoid, small (8 lines or less), pendent, scales rounded and entire at tip. 



21. ABIES CANADENSIS. 

 f 3 . Cylindrical, large (2-4 in.), erect; bracts conspicuous, exserted; scales 



falling from the axis at maturity 22. ABIES BALSAMEA. 



/ 4 . Ovoid or roundish, small, 9 lines or less, scales persistent on the axis at 



maturity 23. LARIX AMERICANA. 



d 2 . Scales few, persistent, bractless; cone 



Oblong and erect, with loosely imbricated scales somewhat thickened at 



the tip, seeds winged all round 27. THUGA OCCIDENTALS. 



Spherical, about - in. in diameter, with 3 pairs of peltate scales. 



74. CHAMAECYPARIS THYOIDES. 



C 3 . Scales 3-lobed bracts each subtending 2-3 closed, indehiscent carpels minia- 

 ture samara (Betula). 

 f. Cones erect, short, scales thin and with barely spreading lobes, wings 



of seed not broader than the body 17. B. LUTEA. 



/" 2 .Cones suberect, ovoid-oblong; scales thicker and with short divergent 



lobes; wing of nutlet not broader than the body 44. B. LENTA. 



f\ Cones pendent, cylindrical and about 



1 in. in length 70. B. POPULIFOLIA. 



If in. in length 43. B. PAPYRACEA . 



C 3 . Scales closed carpels, growing from an elongated receptacle and consolidated 



together. 



d. Dehiscent at maturity along the medium line of the back, and letting out 

 each 1-2 berry-like seeds suspended by extensile threads (Magnolia). Cone 



Cylindrical, curved, 2-3 in. long 1. MAGNOLIA ACUMINATA. 



Oblong, 1-1 in. long 51. MAGNOLIA GLAUCA. 



d*. Indehiscent at maturity and falling away as sarnarse. 



2. LlRIODENDRON TULIPIFERA. 



7>' 2 . Spherical head, hardened and bristling with 2-beaked capsules. 



60. LlQUIDAMBAR STYRACIFLUA. 



ft 3 . Sorosis a spike with bracts and calyx-lobes all thickened and succulent. 



63. MORUS RUBRA. 



