TILIA 153 



and diagnostic. 



a. Leaves essentially the same color on 



both surfaces; northern species l.T. americana 



a. Leaves whitened beneath; southern 



species 2. T. heterophylla 



1, T. americana L. American Linden. Basswood. A large 

 tree up to 40 m. high; bark gray, furrowed; twigs glabrous, green; 

 fruit globose, 6-8 mm. in diameter. Rich woods, Quebec to Mani- 

 toba, south to Tennessee, Arkansas, and Texas (Fig. 219). 



2. T. heterophylla Vent. White Basswood. White Linden. 

 Linn. A large tree, 20-30 m. high, with a diameter of 1. 5 m. ; 

 bark at first gray and smooth, becoming furrowed into flat ridges; 

 twigs glabrous, reddish or yellowish-brown; fruit ellipsoid, 8 mm. 

 long. Rich woods, Florida to Alabama and Missouri, north to West 

 Virginia and New York (Fig. 220). 



HIBISCUS L. (Malvaceae) 



Small deciduous shrubs. Twigs slender, rounded, glabrescent; 

 pith small, continuous, white,bordered with green. Buds not evi- 

 dent, covered by branch vestiges. Leaf- scars alternate, half-round, 

 raised, decurrent in short ridges; bundle-traces about 4, indistinct; 

 stipule- scars small. 



1. H. syriacus L. Rose of Sharon. Shrubby Althaea. Shrub 

 to 3 m. high, or more; twigs gray, at first villous, then glabrous; 

 fruit a capsule 2. 5 cm. long, persistent into winter. Introduced 

 from Asia as a cultivated ornamental, established in roadsides 

 (Fig. 221). 



HYPERICUM L. (Hypericaceae) 



Small deciduous shrubs (most species herbaceous) with flaking 

 bark. Twigs slender, angled; pith relatively large, somewhat por- 

 ous, finally excavated in older stems. Buds solitary, sessile, 

 minute. Leaf-scars opposite, small, triangular; bundle-trace 1; 

 stipule-scars lacking. Fruit a small capsule persistent in winter. 



a. Dried capsule 7-15 mm. long 



b. Shrub 2-6 dm. high; capsule 



7-10 mm. long l.H. kalmianum 



b. Shrub up to 2. 5 m. tall;capsule 



8-15 mm. long 2.H. spathulatum 



a. Dried capsules 4-6 mm. long 3. H. densiflorimi 



