TILIACE42 733 



Leaves hoary-tomentose when they unfold. 

 Leaves soon glabrous. 



Leaves coarsely serrate with stout teeth, their veinlets conspicuous; branchlets 

 stout, bright red. 3. T. venulosa (A). 



Leaves finely serrate with straight or incurved teeth, their veinlets less conspicu- 

 ous; branchlets slender, pale reddish brown. 4. T. littoralis (C). 

 Leaves crenately serrate, glaucescent on the lower surface. 5. T. crenoserrata (C). 

 Leaves covered below early in the season with articulate hairs, becoming glabrous 



or nearly glabrous. 



Leaves thin, coarsely serrate, green or glaucescent on the lower surface, with or with- 

 out tufts of axillary hairs; summer shoots not pubescent. 6. T. floridana (C). 

 Leaves subcoriaceous, finely serrate, bluish green and lustrous below early in the 

 season; tufts of axillary hairs minute, usually wanting; summer shoots pubes- 

 cent. 7. T. Cocksii (C). 

 Surface of the leaves pubescent below during the season. 



Lower surface of the leaves covered with short gray firmly attached pubescence; tufts of 

 axillary hairs not conspicuous. 8. T. neglecta (A,C). 



Lower surface of the leaves covered with articulate easily detached hairs. 

 Branchlets without straight hairs. 



Leaves ovate, acuminate, usually obliquely truncate at base, glabrous above, their 



pubescence brownish or white. 9. T. caroliniana (C). 



Leaves oblong-ovate, cordate or obliquely cordate at base, pubescent above early 



in the season. 10. T. texana (C). 



Leaves semiorbicular to broad-ovate, abruptly short-pointed, deeply and usually 



symmetrically cordate at base. 11. T. phanera (C). 



Branchlets covered with straight hairs; leaves ovate, abruptly short-pointed, oblique 



and truncate at base. 12. T. lasioclada (C). 



Surface of the leaves tomentose below during the season with close firmly attached tomen- 



tum. 

 Tomentum white, gray, or brown; leaves usually glabrous on the upper surface; branch- 



lets and winter-buds glabrous (occasionally pubescent in varieties of 13}. 

 Branchlets slender; petioles not more than 1^' in length; leaves oblong-ovate, acumi- 

 nate or abruptly pointed, oblique and truncate or cordate at base; tomentum on the 

 leaves of upper branches often brown; flowers '-$' long. 13. T. heterophylla (A, C) . 

 Branchlets stout; petioles .up to 3' in length; leaves oblong-ovate, acuminate, obliquely 

 truncate at base; tomentum always white; flowers iV 2' l n g- 



14. T.monticola(A). 



Tomentum pale or brownish; leaves thickly covered above early in the season with fas- 

 cicled hairs; branchlets tomentose; winter-buds pubescent. 15. T. georgiana (C). 



i 



1. Tilia glabra Vent. Linden. Bass Wood. 

 , Tilia americana L. 



Leaves broad-ovate, contracted at apex into a slender acuminate entire point, obliquely 

 cordate or sometimes almost truncate at base, coarsely serrate with incurved glandular 

 teeth, often slightly pubescent when they first appear soon glabrous with the exception of 

 tufts of rusty brown hairs in the axils of the principal veins below, thick and firm, dark dull 

 green on the upper surface, lighter, yellow-green and lustrous on the lower surface, 5'-6' 

 long and 3'-4' wide; turning pale yellow in the autumn before falling; petioles slender, 

 H'-2' in length. Flowers \' long, opening early in July on slender slightly angled pubes- 

 cent pedicels, in few-flowered slender-branched glabrous cymes; peduncle slender, gla- 

 brous, the free portion 3^'-4' long, its bract rounded or pointed at apex, 4 '-5' long, l'-lf 

 wide, decurrent nearly to the base or to within \'-V of the base of the peduncle; sepals 

 ovate, acuminate, densely hairy on the inner surface and slightly pubescent on the outer 



