Feb., 1913.] 
The Ohio Dogbanes. 
79 
THE OHIO DOGBANES. 
Lillian E. Humphrey. 
Apocynaceae. Dogbane Family. 
Perennial erect or trailing herbs, shrubs, or vines; usually with 
milky acrid sap. Leaves simple, more commonly opposite, 
without stipules; flowers hvpogenous, sympetalous, tetracyclic, 
with actinomorphic perianth; andrecium pentamerous, the 
stamens distinct, united with the corolla at least at the base; 
pollen not in masses; gynecium of two united carpels, but the 
ovularies separating below the style; fruit usually two follicles; 
seeds often appendaged with a tuft of long hairs. 
Key to the Genera. 
1. Flowers solitary, large, axillary; trailing herbs. Vinca. 
1. Flowers cymose; erect herbs. Apocynum. 
Vinca L. Periwinkle. 
Perennial trailing herbs with opposite, evergreen leaves, and 
large, solitary, axillary flowers. Stem slightly woody; calyx 
segments acuminate; corolla salverformed, blue; stamens included; 
disk of 2 glands alternate with the two carpels; follicles with 
several ovules and seeds; seeds oblong-cvlindric, without hairs. 
Vinca minor L. Periwinkle. Leaves glabrous oblong to ovate, 
entire, Ann, shining, green on both sides, narrowed at the base, 
short petioled. Escaped from cemeteries and gardens. Huron, 
Montgomery, Vinton, Portage, Williams, Stark, Wayne, Coshoc¬ 
ton, Richland, Auglaize, Lawrence. 
Apocynum L. Dogbane. 
Perennial erect herbs with opposite, entire, leaves and white 
or pink flowers in corymbed cymes. Corolla usually campanu- 
late, having five small triangular appendages within alternating 
with the stamens; follicles slender; long, terete, containing numer¬ 
ous ovules with tufts of long hairs. 
Key to the Species. 
1. Corolla much longer than the ovate pointed divisions of the calyx; 
branches diverging; flowers M to inch long. 2. 
1. Corolla not longer than the lanceolate divisions of the calyx; branches 
upright, ascending; terminal cyme not extending above the lateral 
branches; flowers small. 3-16 to H inch long. 3. 
2. Corolla campanulate, recurved, not angled, pinkish, narrowed in the 
throat. A. androsaemifolium. 
2. Corolla urceolate, five-angled, white or only slightly tinged with pink, 
spreading. A. urceolifer. 
3. Leaves petioled. 4. 
3. Leaves not petioled, lower ones more or less clasping, the upper ones 
sessile. A. hypericifolium. 
