796 CISTACEAE 



clustered or paniculate. Sepals 3-5, persistent, when 5 the 2 exterior ones 

 smaller and scale-like, the 3 inner convolute. Petals 5 or 3, or sometimes want- 

 ing, often fugacious. Stamens 8, hypogynous. Gynoecium of several united 

 carpels. Ovary sessile, 1 -several-celled. Ovules orthotropous, stalked. Styles 

 united. Stigma entire or 3-lobed. Capsule dehiscent by valves. Seeds several 

 or numerous. Embryo slender, straight or curved. Endosperm starchy or 

 fleshy. 



Petals 5, yellow, fugacious or wanting. 



Styles obsolete or relatively short : leaves with flat or merely revolute blades. 1. HELIANTHEMUM. 



Styles slender, elongated: leaves scale-like, sometimes subulate. 2. HUDSONIA. 



Petals 3, not yellow, persistent. 3. LECHEA. 



1. HELIANTHEMUM Pers. 1 



Woody herbs or low shrubby plants. Leaves with flat or revolute blades. Flowers 

 complete or some species with both petaliferous and apetalous ones, the petal iferous often 

 showy, with 12-30 long stamens and 20-60 or rarely 8-10 ovules in each ovary. Apetalous 

 flowers with 3-8 short stamens and 6-20, or rarely 3-6 ovules in each ovary, as a rule less 

 than one-half the number in the petaliferous flowers. Style obsolete or short : stigma capi- 

 tate or 3-lobed. Capsules of the petaliferous larger than those of the apetalous flowers. Em- 

 bryo curved. The plants flower in the spring or in the spring and summer. FROST-WEED. 



Flowers all alike and petaliferous. 1. H. Carolinianum. 



Flowers of two kinds, some petaliferous others apetalous. 

 Petaliferous and apetalous flowers in the same clusters. 



Flowers in a dense terminal cyme. 2. H. corymbosum. 



Flowers in scattered or panicled clusters. 

 Flower-clusters scattered or solitary. 



Sepals becoming 6-8 mm. long: lateral nerves of leaves not promi- 

 nent beneath. 3. H. arenicola. 

 Sepals becoming 4 mm. long : lateral nerves of leaves prominent be- 

 neath. 4. H. Georgianum. 

 Flower-clusters in more or less elongated thyrsoid panicles. 

 Sepals of the apetalous flowers fully 2 mm. long at maturity. 



Sepals canescent-puberulent. 5. H. NasJni. 



Sepals hirsute. 6. H.tlnjrs<>i<lfuni. 



Sepals of the apetalous flowers less than 2 mm. long. 7. H. rosmarinifolium. 



Petaliferous flowers solitary or few, vernal; apetalous flowers numerous, 



clustered, autumnal. 

 Petaliferous flowers 1 or 2, their capsules far overtopped by the apetalous 



inflorescence. . 8. //. Canadenge. 



Petaliferous flowers 5-12, the apetalous inflorescence on short lateral 



branches. 9. H. majus. 



1. Helianthemum Carolinianum Michx. Stems villous-hirsute or hirsute, erect or 

 ascending, 1-3 dm. tall, often branched at the base, thence simple, or corymbose above : 

 leaves few, often mostly at the base of the stem ; blades obovate, oval, oblong or somewhat 

 spatulate, 2-5 cm. long, obtuse or apiculate, ciliate, the upper ones manifestly petioled : 

 flowers few : pedicels becoming 1-2 cm. long : sepals various, the larger ovate, becoming 1 2- 

 14 mm. long, acuminate, involute at the apex, much longer than broad : corolla yellow, 

 2.5-3 cm. broad : petals very delicate : capsules subglobose, 7-9 mm. in diameter. 



In pine lands, South Carolina to Florida and Texas. 



2. Helianthemum corymbosum Michx. Stems finely and densely canescent, erect, 

 branching from the base, 1.5-3 djn. high : leaf-blades oblong, or the lowest obovate, 2-2.5 

 cm. long, obtuse or acutish, 6-10 mm. wide, entire, slightly revolute in drying, pale be- 

 neath, dark green above, short-petioled : flowers in a nearly naked terminal fastigiate 

 cyme, the petaliferous with 25-30 stamens and 20 ovules, the apetalous with 3-6 stamens 

 and 9 ovules : corolla 16-20 mm. broad : pedicels slender, 6-16 mm. long : apetalous 

 flowers nearly sessile : calyx of both kinds woolly-pubescent : outer sepals about equalling 

 the inner : capsules of the larger flowers 4-6 mm. broad, many-seeded, those of the 

 apetalous ones smaller and few-seeded. 



In sandy soil, Virginia and North Carolina to Florida and Louisiana. 



3. Helianthemum arenicola Chapm. Stems canescent-tomentulose, several from the 

 woody base, erect or spreading, 1-2 dm. long, often branched above : leaf-blades linear- 

 oblong, 1-2.5 cm. long, obtuse, only the midrib prominent beneath : flowers solitary or 

 few in terminal clusters, the petaliferous with 25 stamens and 20 ovules, the apetalous 

 with 5 stamens and 10 ovules : sepals various, the larger ovate or oval-ovate, becoming 6-8 

 mm. long : corolla yellow, 16-20 mm. broad : capsules oval, about 4 mm. long. 



In shifting sand, along or near the coast, Florida. 



1 Kevised by Dr. John H. Barnhart. 



