2(1 ). Twining vines 2. Trachelospermum 



2. Plant erect, never twining 3. Apocynuin 



1. Amsonia Walt. Blue-star 



Caulescent herbaceous perennials; leaves alternate or subverticillate, not glan- 

 dular; inflorescence thyrsiform, terminal or occasionally lateral, bearing several 

 to many flowers; calyx 5-parted. the lobes essentially equal, scarcely imbricate, 

 without squamellae; corolla salverform, the limb regularly 5-parted. the lobes 

 sinistrorsely contorted; anthers not connivent, without an enlarged connective, 

 wholly included; ovary apocarpous, without a nectary, containing numerous ovules; 

 follicles terete, continuous or more or less moniliform; seeds numerous, naked, 

 rather corky. 



A genus of about 25 species in North America and one in Japan. 



1. Corolla glabrous externally 1. A. glaberrima. 



1. Corolla pubescent externally (2) 



2(1). Calyx glabrous; leaves thinly membranaceous, opaque above 



2. A. tabernaemontana. 



2. Calyx more or less pilose; leaves firmly membranaceous or subcoriaceous, 



lustrous above 3. A. illiistris. 



1. Amsonia glaberrima Woods. 



Stems to 8 dm. tall, wholly glabrous; leaves alternate, firmly membranaceous, 

 oblong-elliptic to narrowly lanceolate, to 8 cm. long and 2 cm. wide, acuminate, 

 narrowed at the base, wholly glabrous, opaque on both sides, the petioles 2-4 mm. 

 long; inflorescence rather diffuse, scarcely surpassing the foliage, bearing 

 several to numerous medium-sized azure flowers; pedicels 3-4 mm. long, glabrous; 

 calyx lobes ovate-triangular, acute, about 1.5 mm. long, glabrous; corolla wholly 

 glabrous externally, the tube 6.5-7 mm. long, about 1 mm. in diameter at the 

 base, somewhat dilated above the insertion of the stamens, not constricted at 

 the orifice, the lobes 6-7 mm. long, glabrous, somewhat spreading; follicles rela- 

 tively slender, continuous, 8-10 cm. long, glabrous. 



In dense wet lowland woods, about pools, in wet savannahs and low pinelands 

 in extreme s.e. Tex., Mar.-Nov.; also La. 



2. Amsonia tabernaemontana Walt. 



Stems 3-10 dm. tall; leaves alternate, rather thinly membranaceous, ovate to 

 oblong-elliptic or lanceolate, 6-15 cm. long, to 5 cm. broad, acute to acuminate 

 at apex, obtuse to broadly acute at the base, wholly glabrous to finely puberulent 

 beneath, opaque on both sides, the petioles 3-6 mm. long; inflorescence barely 

 surpassing the foliage, bearing several to numerous azure flowers; pedicels 3-6 

 mm. long; calyx lobes ovate to ovate-lanceolate. 1-2 mm. long, glabrous; corolla 

 more or less pilose externally, the tube 6-8 mm. long, about 1 mm. in diameter at 

 the base, somewhat dilated above the insertion of the stamens, not constricted at 

 the orifice, the lobes 4-7 mm. long, spreading; follicles relatively slender, con- 

 tinuous. 8-12 cm. long, glabrous. 



In sandy soil about lakes and along streams in n.e. Tex. and Okla. (Waterfall), 

 Mar .-May; from Pa., s. to Ga. and s.w. to Tex. 



Those plants with lanceolate to narrowly oblong-elliptic leaves 6-15 cm. long 

 and 1-2.5 cm. wide have been placed in var. salicifolia (Pursh) Woods, (var. 

 Gattinqeri Woods.) 



This species, along with A. f^laherriina and A. illiistris, form an extremely close 

 alliance, and it is questionable as to whether or not they should be maintained 

 as separate species rather than variants of one complex unit. The degree of 



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