KEY, BASED UPON LEAVES. 11 



e. Rib single at first but soon sending off a strong vein on each side and 



leaves 3-lobed, 2-lobed or entire 32. SASSAFRAS OFFICINALE. 



e 3 . Ribs three at first, but soon five by branching, leaves alternate, base of 



petiole concave and fitting over the axillary bud. 

 Obscurely 3-5 lobed with broad shallow sinuses. 



13. PLATANUS OCCIDENTALS. 



5-lobed with narrow and deeper sinuses. .135. PLATANUS RACEMOSA. 

 e 3 . Ribs 5-7 from commencement; leaves 



f. Opposite, base of petiole subtending (not covering) the axillary bud. 

 g. Moderately incised with broad lobes which are 



Sparingly sinuate-toothed 7. ACER SACCHARINUM. 



Irregularly serrate and notched 53. ACER RUBRUM. 



Sharply and finely doubly serrate 79. ACER PENNSYLVANICUM. 



/. Alternate, tendril bearing vine 78. VITIS AESTIVALIS. 



g. Deeply incised with more or less acute sinuses and narrow divisions. 

 Star-shaped, lobes glandular serrate. 



60. LlQUIDAMBAR STYRACIFLUA 



Palmate, lobes incisely toothed 26. ACER DASYCARPUM. 



C 2 . Linear, sessile in delicate 2-ranked sprays 119. TAXODIUM DISTICHUM. 



c 3 . Needle-shaped without distinction of blade and petiole short, about 1 in. 



in length, soft and in fascicles of many each 23. LARIX AMERICANA. 



6 2 . Compound leaves, 



C. Palmate with usually 



7 obovate leaflets 6. JEscuLUS HIPPOCASTAUM. 



5 oblong-lanceolate leaflets 127. JEscuLUS CAHFORNICA. 



C 2 . Pinnate and with an odd terminal leaflet, rachis 



d. Finished with prickles 106. XANTHOXYLUM CLAVA-HERCULIS. 



rf 2 . Not-finished with prickles ; leaflets all 

 e. Petiolulate, leaflets 

 /. 21-41, each with one or two pairs of glandular teeth at its base. 



4. AlLANTHUS GLANDULOSUS. 

 / 2 . 11-15, 



With prickle-like stipules, entire 80. ROBINIA PSEUDACACIA. 



With stipules, serrate 84. PYRUS SAMBUCIFOLIA. 



/ 3 . 7-9, ovate or lance-oblong, entire or obscurely serrate; 



Petioles and branchlets glabrous 10. FRAXINUS AMERICANA. 



Petioles and branchlets velvety pubescent.31. FRAXINUS PUBESCENS. 

 / 4 . Lateral leaflets 



Petiolulate, irregularly toothed 54. ACER NEGUNDO. 



Sessile, subentire .77. PTELEA TRIFOLIATA. 



e 2 . Sessile or subsessile 



f. Numerous (15-1 7) and pubescent, especially along the petiole and rachis. 

 g. Leaflets ovate-lanceolate, finely serrate; pubescence of short, rust- 

 colored clammy hairs. 



Fruit subovoid, viscid-pubescent 14. JUGLANS CINEREA. 



Fruit globose, roughly dotted (not viscid-pubescent). 



35. JUGLANS NIGRA. 

 gr 2 . Leaflets lance-oblong, coarsely serrate; pubescence of copious, longer 



and white hairs 5. RHUS TYPHINA. 



/ 2 . 11-13 115. CARYA AQUATICA. 



/ 3 . (5-11). 



