APOCYNACEAE. 737 



cordate-orbicular, thick, entire or repand. spongy, and with the petioles and stolons 

 densely covered with minute pits; primary leaves spatulate; tubers linear-oblong, 

 thicker; seeds rough; capsule longer than the calyx. In ponds, N. J. and Del. to 

 Fla. and Tex. May Aug. 



3. Limnanthenmm nymphaeoides (L.) Hoffm. & Link. WATER LILY 

 FLOATING HEART. (I. F. f. 2892.) Stems long, branched, the upper nodes 

 bearing a petioled leaf and a cluster of flowers, or the upper internodes very short 

 and their leaves apparently opposite. Petioles stout, mostly longer than the ovate- 

 orbicular firm blades, which are 5-10 cm. broad; pedicels stout, becoming 7-15 cm. 

 long; corolla-segments short-fringed. Nat. in ponds, D. C. Native of Europe and 

 Asia. May-July. 



Family 5. APOCYNACEAE Lindl. 

 Dogbane Family. 



Perennial herbs, shrubs, vines, or some tropical genera trees, mostly 

 with an acrid milky juice, with simple estipulate leaves, and perfect 

 regular 5-parted flowers. Calyx inferior, persistent, the lobes imbricated 

 in the bud. Corolla gamopetalous, its lobes convolute in the bud and 

 often twisted. Stamens as many as the lobes of the corolla, alternate 

 with them, inserted on the tube or throat ; anthers 2-celled ; pollen-grains 

 simple. Ovary superior, or its base adherent to the calyx, of 2 distinct 

 carpels, or i -celled, with 2 parietal placentae, or 2-celled; ovules anatro- 

 pous or amphitropous ; style simple, or 2-divided ; stigma simple. Fruit 

 usually of 2 follicles or drupes. Seeds often appendaged ; endosperm 

 fleshy; embryo straight; radicle terete, usually shorter than the coty- 

 ledons. About 130 genera and 1050 species, very widely distributed, 

 mostly in tropical regions. 



Leaves alternate ; erect herbs. i. Amsonia. 

 Leaves opposite ; vines or herbs. 



Flowers large, axillary, solitary. 2. Vinca. 

 Flowers small, cymose. 



Erect or diffuse herbs ; corolla campanulate to urceolate. 3. Apocynum. 



High-climbing vines ; corolla funnelform. 4. Trachelospermum. 



i. AMSONIA Walt. 



Perennial herbs, with alternate membranous leaves, and rather large blue or 

 bluish flowers, in terminal thyrsoid or corymbose cymes. Calyx 5-parted, the 

 segments acuminate. Corolla mostly salverform, the tube cylindric, but somewhat 

 dilated at the summit, villous within. Stamens included; anthers ovate or oblong. 

 Disk none. Ovary of 2 carpels, connected at the top by the filiform style; ovules 

 in 2 rows in each cavity, numerous; stigma appendaged by a reflexed membrane. 

 Fruit of 2 erect cylindric several-seeded follicles. Seeds obliquely truncate at each 

 end, not appendaged. [Named for Charles Amson of South Carolina.] About 12 

 species, natives of N. Am. and eastern Asia. Besides the following, 5 others occur 

 in the southern and western U. S. 



Leaves ovate to ovate-lanceolate ; pods divergent. i. A. Amsonia. 



Leaves lanceolate to linear-lanceolate ; pods ascending. 2. A. salicifolia. 



1. Amsonia Amsonia (L.) Britton. BROAD-LEAVED AMSONIA. Glabrous 

 or nearly so, 6-12 dm. high. Leaves ovate or ovate-lanceolate, entire, acuminate, 

 narrowed at the base, sometimes pubescent beneath, 5-10 cm. long, 2-5 cm. wide; 

 petioles 4-8 mm. long; pedicels bracteolate at the base; calyx about 2 mm. long, 

 its segments subulate; corolla 12-18 mm. long, beaked by the convolute limb in the 

 bud, its lobes linear and about as long as the tube; follicles 5-10 cm. long, about 

 4 mm. thick, attenuate at the apex, glabrous; seeds papillose. In moist soil, Penn. 

 to Mo., Ky., Fla. and Tex. April-July. 



2. Amsonia salicifolia Pursh. WILLOW- LEAVED AMSONIA. Similar to the 

 preceding, but the leaves much narrower, lanceolate to linear-lanceolate. 8-15 cm. 



