KEY, BASED UPON FLOWERS. 5 



h*. Oblong, undulately crenate-tootlied, peduncles shorter than 

 petioles ; acorn 



Less than 1 in. in length 67. Q. PRINUS. 



More than 1 in. in length 116. Q. MICHEAUXII. 



/it 5 . Lanceolate-oblong; sharply undulate-toothed ; acorn small. 



68. Q. MUHLENBEKGII. 



h*. Elliptical or oblong, evergreen 117. Q. VIRENS. 



h\ Obovate-spatulate, partly deciduous 118. Q. AQUATICA. 



gr 2 . Leaves with teeth and lobes acute and bristle-pointed; acorns matur- 

 ing the second year (and hence on old wood); leaves 

 h. Moderately pinnatifid ; cup very shallow and saucer-shaped; 



scales fine 15. Q. BUBRA. 



h 9 . Deeply pinnatifid; lobes 



t. Rather broad; inner bark yellowish 93. Q. TINCTORIA. 



i 2 . Narrow; sinuses broad and rounded; acorn 



Ovoid- oblong, - invested in a coarse-scaled cup. 



69. Q. COCCINEA. 



Flattened-globular, invested in fine-scaled cup. 



94. Q. PALUSTRIS. 



/'. Involucre 2-4-valved, becoming hard and prickly and inclosing 1-3 

 sweet, edible, flattened, subglobose nuts ; sterile flowers in catkins. 



40. CASTANEA VESCA. 

 / 3 . Involucre 4-valved and inclosing two, 3-cornered, edible nuts. 



16. FAGUS FERRUGINEA. 



e 3 . Fertile flowers in short catkins ; nuts small and acheniuin-like ; sterile 

 flowers destitute of calyx ; leaves simple. 



/. Nutlet inclosed in a bladder-like bag 41. OSTYRA VERGINICA. 



/ 9 . Nutlet not inclosed but subtended by an enlarged leafy bract. 



42. CABPINUS CAROLINIANA. 



d?. Both staminate and pistillate flowers in catkins. 

 e Ovary and pod 2-celled, many-seeded. 



60. LlQUIDAMBAR STYRACIFLUA. 



e 2 . 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 together under each scale of the cone-like catkin (Betula); bark 



g. Brown and close, catkins erect 44. B. LENTA. 



j/ 2 . Yellowish-gray and ragged, catkins sub-erect 17. B. LUTEA. 



gr 3 . White, and leaves. 



Deltoid, smooth both sides 70. B. POPULIFOLIA. 



Ovate, hairy on veins beneath 43. B. PAPYRACEA. 



gr 4 . Reddish-brown, shaggy 95. B. NIGRA. 



/*. Calyx regular and succulent in fruit 63. MORUS RUBRA. 



e 3 . Ovary 1 -celled and many-seeded, the seeds at maturity furnished with a 



hairy tuft (Salicacew). 



f. Bracts of the catkins entire ; calyx wanting ; stamens 2-7 (Salix); cat- 

 kins on leafy branchlets with yellowish, deciduous scales; capsules 

 glabrous ; stamens 3-5 ; petioles 

 g. Glandular; scales of catkin entire; leaves 



Narrow-lanceolate; fruiting catkins rather dense 45. S. NIGRA. 



Lanceolate or ovate lanceolate, glaucous beneath, fruiting catkins 

 verv loose. . . 71. S. AMYGDALOIDES 



