KEY, BASED UPON FRUIT. 13 



e 3 . In open panicles, granular-coated 



in. long; leaves oblong 132. ARBUTUS MENZIESII. 



^ in. long; leaves lanceolate 280. ARBUTUS ARIZONICA. 



e*. Singly on the jointed flattened stem Ib4. OPUNTIA TUNA. 



c 9 . Fleshy, with custard like edible pulp 76. ASIMINA TRILOBA. 



c 10 . Berry-like ponie, f in. in diameter and borne in dense clusters. 



84. PYRUS SAMBUCIFOLIA. 

 c 11 . Hesperidum seeds in juicy pulp and rind leathery. 



Subglobose. flattened at the ends 103. CITRUS AURANTIUM. 



Globose-oblong, mamniillate at the extremity 104. CITRUS LIMONUM. 



c 12 . Achenium. 



3-4-angled and with membranous wing-like margins. 



108. CLIFTONIA LIGUSTRINA. 

 Linear oblong, tipped with the prolonged tail-like style. 



130. CERCOCARPUS PARVIFOLIUS. 



c 13 . Baccate but with dry spongy pericarp 175. YUCCA ARBORESCENS. 



b 2 . Dehiscent pericarp, 

 c. Subglobose, and 



(I. Coriaceous or woody, dehiscent by 



e. 2-3 valves and containing one or very few large seeds with smooth shining 

 coat and a large scar (AZsculus), fruit 



Prickly and leaflets 7 6 ^EscULUS HIPPOCASTANUM. 



Smooth and leaflets 5 127. ^ESCULUS CALIFORNICA. 



e 2 . 4 more or less distinct valves (Carya). 

 f. Epicarp thick and separating quite freely to the base ; nut ridged, with 



thick shell, globular-ovoid and 

 g. Flattened, 



1 in. or less in length 36. CARYA ALBA. 



1 in, or more in length 64. CARYA SULCATA. 



gr 2 . Not so much flattened, usually 4-angled 90. CARYA TOMENTOSA. 



f* Epicarp only moderately thick and nut of medium size, moderately 



ridged and with shell of medium thickness 65. CARYA PORCINA. 



/ 3 . Epicarp thin, nuts small and thin-shelled ; kernel 

 g. Astringent and bitter ; sutures of epicarp very prominent ; nut 

 Quite smooth, whitish and only slighly compressed. 



37. CARYA AMARA. 

 Rough, reddish, strongly compressed and angled. 



115. CARYA AQUATICA. 

 g*. Slightly if at all bitter, nut whitish and sutures moderately prominent. 



91. CARYA MICROCARPA. 

 e 3 . 5-20 valves recurving from central axis and liberating numerous fine 



seeds 158. RHODODENDRON CALIFORNICUM. 



^ 2 . Covered with spines ; dehiscent 

 e. By four valves ; nuts 



Sharply 3 angled, 2 together, involucre soft-prickly. 



16. FAGUS FERRUGINEA. 

 Subovoid, flattened, 1-3 together, involucral spines very sharp and 



hard 40. CASTANEA VESCA. 



e 2 . Irregularly ; spines many-branched ; nut maturing the second year. 



139. CASTANOPSIS CHRYSOPHYLLA. 



e*. Into three cocci, each liberating a single seed 189. RICINUS COMMUNIS. 



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



and containing numerous seeds furnished with silky down ; capsule 

 d. Oblong-conical, small and thin walled ; leaves 

 e. Orbicular ovate and 



/. Coarsely dentate 18. POPULUS GRANDIDENTATA. 



f' 2 . Serrate, short- pointed .72. POPULUS TREMULOIDES. 



Sinuate, wooly tomentose beneath 96. POPULUS ALBA. 



Linear lanceolate, tomentose on midrib above and petiole. 



45. SALIX NIGRA. 



e*. Ovoid-oblong, larger and thicker walled; leaves 

 /. Broad-ovate, obscurely crenate-serrate obtuse or rounded at apex. 



97. POPULUS HETEROPHYLLA. 



/*. Ovate or ovate-lanceolate, acuminate, whitish and reticulate-veined 

 beneath . 47. P. BALSAMIFERA. 



