— 
rl, 
Studies in the North American Convolvulaceae. III. Calycobolus, 
Bonamia, and Stylisma 
HoMER DOLIvVER HOUSE 
The Dicranostyleae, to which belong these three genera to- 
gether with Cressa and Evolvulus, is characterized by bifid styles 
and these divisions sometimes again cleft, as in Evo/vu/us, valvular 
and usually 2-celled, 2-4-seeded capsules. The genus Calycodo- 
lus (Prevostea) has been placed in the Poraneae by Hallier, but the 
characters of the style and capsule in Ca/ycodolus are those of the 
Dicranostyleae, while the only character which it has in common 
with Porana is the inequality of the sepals. The genus Dicrano- 
styles Benth, is represented in northern South America by D. scan- 
dens Benth., and the closely allied genus Lysiostyles Benth. by ra 
scandens, 
Ke; to the North American genera of Dicranostyleae 
Outer sepals enlarged, often colored or otherwise different from the 
inner sepals. 1. CALYCOBOLUS. 
Sepals alike or nearly so. 
Divisions of the style entire; stigmas 2; corolla funnelform. 
Stamens included. 
Plants comparatively stout ; sepals leathery, rounded or 
obtuse. 2. BONAMIA. 
Plants slender ; sepals herbaceous, acute or acumi- 
nate. 3. STYLISMA. 
Stamens exserted. 4. CRESSA. 
Divisions of the style each 2-cleft; stigmas 4. 5. EVOLVULUS. 
1. CALYCOBOLUS Willd.; R. & S. Syst. 5: 4. 1819 
Twining or suberect, herbaceous or woody plants. Leaf-blades 
Flowers in axillary clusters. 
Sepals unequal, the outer ones 
inner in texture, shape, co 
included ; filaments dilated and pubescent at the base. Ovary 2- 
celled, 4-ovuled. Style bifid nearly or quite to the ovary, the 
divisions unequal. Stigmas 2, small, capitate. Capsules ovoid. 
Seeds smooth or pubescent. 
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