RHINANTHACEAE 1065 
2-lipped, the upper lip notched. Stamens adnate to near the corolla-throat. Hypogynous 
disk wanting. Stigma 2-lobed. Capsule septicidal, the valves cleft. Seeds numerous. 
Stems or branches erect or ascending. 1. M. acuminata. 
Stems or branches prostrate or decumbent. 
Pedicels about as long as the leaves or somewhat longer. 
Upper sepals ovate, 5-6 mm. long, barely surpassing the others. 2. M. procumbens. 
Upper sepals linear or oblong-lanceolate, 7-9 mm. long, manifestly surpassing 
the others. 3. M. viridis. 
Pedicels several times longer than the leaves. 
Stems sparingly branched, the branches merely procumbent: upper sepal 
over 7 mm. long. 4. M. peduncularia. 
Stems diffusely branched, the branches prostrate: upper sepal less than 7 
mm. long. 5. M. tenuia. 
1. Mecardonia acuminata (Walt.) Small. Stems and branches erect or ascending, 
1-6 dm. tall, leaf-blades spatulate to oblong or elliptic, 2-5 cm. long, serrate, the lower 
ones narrowed into short petioles: pedicels usually somewhat longer than the leaves: 
sepal becoming 8-10 mm. long, ribbed or slightly keeled: corolla white or pink, the upper 
lip bearded within, the lower lip with apiculate lobes: capsules oblong, 5-6 mm. long. 
[ Herpestis nigrescens Benth. ] 
In meadows or wet grounds, Maryland to Florida and Texas. Summer and fall. 
2. Mecardonia procámbens (Mill.) Small. Stems and branches decumbent, 0.5-2 
dm. long. Leaf-blades oval to elliptic or ovate, 1-1.5 cm. long, serrate or crenate-serrate, 
the lower ones short-petioled : pedicels as long as the leaves or slightly longer: upper sepal 
ovate, barely, if at all,-longer than the others, 5-6 mm. long: corolla yellow, 5-7 mm. 
long: capsules 4-5 mm. long. [ Herpestis chamaedryoides H.B.K. ] 
In sand, Florida and Texas. Also in tropical America. Summer and fall. 
3. Mecardonia viridis Small. Resembling M. procumbens but light green and un- 
changed in drying. Stems or branches 1-3 dm. long, merely decumbent: leaf-blades oval 
to ovate or elliptic above, 1-2 cm. long, obtuse, bluntly serrate, contracted into margined 
petioles near the base of the stem : pedicels as long as the leaves or longer: upper sepal 
linear or oblong-lanceolate, becoming 7-9 mm. long, manifestly surpassing the others: 
‘corolla 6-7 mm. long, yellow: capsules about 7 mm. long. 
Insandy soil,coast of Texas. Spring. 
4. Mecardonia pedunculàris (Benth.) Small. Resembling M. procumbens and M. 
viridis but smaller. Stems and branches often less leafy above : leaves fewer: blades nar- 
rower, gradually narrowed into narrow petioles or petiole-like bases: pedicels slender, 
several times longer than the leaves: upper sepal becoming 8-10 mm. long, barely longer 
than the others : corolla about 1 cm. long. 
On prairies, Texas to Arizona. Spring and summer. 
5. Mecardonia ténuis Small. Stems diffusely branched ; branches prostrate, 0.5~4 
dm. long, filiform or wire-like. Leaf-blades spatulate to oblong, oblanceolate or lanceo- 
late, 5-12 mm. long, sharply serrate, except the gradually narrowed base: pedicels filiform, 
several times longer than the leaves: upper sepal oblong-ovate, becoming 6 mm. long, 
barely longer than the others: corolla 6-7 mm. long: capsules 5-6 mm. long. 
On coral rock and in sand, Key West, Florida. 
18. HYDRANTHELIUM H.B.K. 
Annual or perennial amphibious herbs, with floating or creeping stems. Leaves op- 
posite: blades broad. Flowers solitary in the axils. Calyx of 4 partially united sepals. 
Corolla white, 3-lobed. Stamens 3, exserted : filaments adnate as far as the throat of 
the corolla-tube : anther-sacs distinct, parallel. Stigma 2-lobed. Capsule membranous, 
2-valved. Seeds curved. 
1. Hydranthelium Bgénse hips & Endl. Aquatic, minutely pubescent. Stems 
several cm. long, branched : upper leaf-blades cuneate, obovate or suborbicular, 1-1.5 cm. 
long, shallowly toothed above the base: pedicels 5-12 mm. long: calyx-lobes lanceolate, 
acute : capsules subglobose or ovoid-globose. 
In swamps, near New Orleans, Louisiana. Alsointropical South America. Not recently collected. 
19. GRATIOLA L. 
Annual or perennial rather succulent herbs, with glabrous or softly pubescent foliage. 
Leaves opposite: blades entire or toothed, rather fleshy. Flowers solitary on axillary 
peduncles. Calyx sessile in 2 bractlets: sepals 5, nearly distinct. Corolla white, yellow 
or purplish, 2-lipped. Stamens 2, included. Staminodia wanting, scale-like or filiform. 
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