16 KEY, BASED UPON FRUIT. 



f 2 . About i enveloping the small ovoid nut f in. long : scales thin. 



68. Q. MUHLENBERGII. 



Long, narrow nut often 2 in. long 160. Q. LOBATA. 



3 . About ^ enveloping the nut 



g. Thick, scales very roughly tubercled, edge of cup rather inturned 

 after shedding the nut ; nut usually long-ovoid. .38. Q. ALBA. 

 gr 2 . Thinner, scales thinnish ; leaves 



Deciduous ; peduncles shorter than petioles. 



67. QUERCUS PRINUS. 

 Subpersistent ; acorns sessile or nearly so. 



137. QUERCUS AGRIFOLIA. 

 /*. Scarcely enveloping the oblong-ovoid nut about 1 in. in length. 



116. QUERCUS MICHAUXII. 



p. About \ or more enveloping the nut ; peduncles longer than the 

 petioles ; nut 



in. long, light brown 66. QUERCUS BICOLOR. 



i in. or less long, dark brown 117. QUERCUS VIRENS. 



/*. About \ or more enveloping the nut ; peduncles 



g. Longer than the petioles 66. Q. BICOLOR. 



gr 2 . Shorter than the petioles ; scales 



Very loosely appressed, forming a moss-like fringed margin of 



CUp 39. Q. MACROCAKPA. 



More closely appressed and not forming a moss-like fringe. 



92. Q. OBTUSILOBA. 



e s . On wood of the preceding season '(i. e. maturation biennial) ; cup 

 /. Very shallow, almost flat and with long-linear recurved scales. 



138. QUERCUS DENSIFLORA. 

 / 9 . Saucer-shaped, ^ enveloping the nut. which is 



1 in. or less in length ; saucer thin 15. Q. RUBRA. 



2 in. or less in length ; saucer usually thick. 161 Q. CHRYSOLEPIS. 

 \ enveloping the ovoid nut 162. Q. CALIPORNICA. 



gr 2 . Flattened-globose ; leaves 



Sinuate-pinnatifid with wide sinuses 94. QUERCUS PALUSTRIS. 



Obovate-spatulate, entire 118. QUERCUS AQUATICA. 



f 3 . Top-shaped, -| enveloping the acorn ; scales thin and coarse ; 



Inner bark of tree reddish 69. Q. COCCINEA. 



Inner bark yellowish 93. Q. TINCTORIA. 



rf 2 . Club-shaped, short, surrounded with stiff hairs, tipped with the persist- 

 ent recurved style and arranged in globular heads, which are 



Solitary ... 13. PLAT ANUS OCCIDENTALS. 



2-7 together in a uioniliform spike 135. PLATANUS RACEMOSA. 



cP. Achenium-like, small and borne in short catkins, 



Inclosed in a membranous inflated sac, catkin hop-like. 



41. OSTRYA VlRGINICA. 



Subtended by a large leafy bract 42. CARPINUS CAROLINIANA. 



e 5 . Nut-like, dry, not invested with an involucre. 



Smoothish, globose, about in diameter, in cymes with leaf-like bract 



attached 3. TILIA AMERICANA. 



Rough, with scale-like points, ovate, coriaceous. 



114. PLANERA AQUATICA. 

 e 6 . Pod (legume) which is 

 d. Oblong, flat, about 2 in. broad and curved. 



27. GYMNOCLADUS CANADENSIS. 

 d*. Linear or nearly so 



10-18 in. long, contorted and twisted.. 28. GLEDITSCHIA TRIACVNTHOS. 

 4-6 in. long, subterete, compressed between the seeds and thick- 



valved 129. PROSOPSIS JULIFLORA.. 



3-4 in. long, 2-8 seeded and thin valved. 



128. CERCIDIUM TORREYANUM. 

 d s . Obliquely ovate (1-2 in. long), long stalked and mostly 1-seeded. 



109. GLEDITSCHIA MONOSPERMA. 



e? 4 . Ovate, compressed and with accrescent calyx 154. DALEA SPINOSA. 



c 7 . Pome ; capsules 

 d. Cartilaginous ; fruit 



