HOUGH'S AMERICAN WOODS. 



g. Moderately incised with broad lobes which are 



Sparingly sinuate-toothed 7. ACER SACCHARINUM, WANO. 



Irregularly serrate and notched 53. ACER RUBRUM. 



Sharply and finely doubly serrate 79. ACER PENNSYLVANICUM. 



/*. Deeply incised with more or less acute sinuses and narrow lobes. 

 h. Star-shaped, lobes glandular serrate. . . 60. LIQUIDAMBAR STYRACIFLUA. 

 /t 3 . Palmate 



Lobes incisely toothed 26. ACER DASYCARPUM. 



Lobes furnished with 2-4 secondary lobes. .152. A. MACROPHYLLUM. 



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



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



c 3 . Needle-shaped triangular, short, soft and in fascicles of many each 



!-!$ in. long ; bracts of core included 23. LARIX AMERICANA. 



1-1 f in. long ; bracts exserted 250. LARIX OCCIDENTALS. 



2 . Compound Leaves. 



c. Palmate, with usually 



7 obovate leaflets 6. JESCULUS HIPPOCASTANUM. 



5 oblong-lanceolate leaflets 127. ^ESCULUS CALIFORNICA. 



c\ Pinnate with an odd terminal leaflet, rachis 



(1. Furnished with prickles 10G. XANTHOXYLUM CLAVA-HERCULIS. 



(V. Not furnished with prickles ; leaflets all 

 f. Petiolulate, leaflets 

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



4. AlLANTHUS GLANDULOSUS. 

 /*. 11-15, 



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



With foliaceous deciduous stipules 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 . 3-5 ; lateral leaflets 

 <j. Petiolulate and 



//. Irregularly toothed 54. ACER NEGUNDO. 



W. Evenly serrate ; leaves and young shoots 



Glabrous 157. SAMBUCUS GLAUCA. 



Pubescent 229. SAMBUCUS MEXICANA. 



X. Sessile, subentire 77. PTELEA TRIFOLIATA 

 3-9. generally petiolulate, 



Entire or serrate, acuminate 212. FRAXINUS VELUTINA. 



Coarsely serrate above middle 231. FRAXINUS DIPETALA. 



e 2 . Sessile or subsessile 



/. Numerous and pubescent, especially along the petiole and rachis. 

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

 clammy hairs; leaflets 



7-13, yellow-glandular-dotted 115. CARYA AQUATICA. 



11-17, fruit subovoid, viscid, pubescent 14. JUGLANS CINEREA. 



9-23, fruit subglobose, nut obscurely sulcate. 



190. JUGLANS CALIFORNICA. 

 gf 2 . Leaflets lance-oblong, coarselv serrate ; 



9-23. finely pubescent 223. JUGLANS RUPESTRIS. 



11-31, velvety pubescent 5. RHUS TYPHINA. 



/ 2 . 5, quite glabrous; fruit a ridged nut about 1 in. long with thick 



epicarp 36. CAHYA ALBA. 



/'. 5-7 or-9, 



g. Glabrous, epicarp thin; nut 



Small, thin shelled 91. CARYA MICROCARPA. 



Larger, moderately thick-shelled 85. CARYA PORCINA. 



<7' 2 . Tomentose; fruit a samara 187. FRAXINUS OREGONA. 



/*. 7-9, epicarp thick and woody, leaflets 



Puberulent ; bark shaggy 64. CARYA SULCATA. 



Tomentose and odorous 90. CARYA TOMENTOSA. 



/ 5 - 7-11, 



Lanceolate, acute at base, minutely glandular and pubescent 

 beneath. . 37. CARYA AMARA. 



