CISTACE^E. (ROCK-ROSE FAMILY.) 35 



base. Style hooked at the summit. An upright simple hairy perennial herb, 

 with numerous ovate-lanceolate, acuminate and entire leaves, and 1-3 short- 

 stalked greenish nodding flowers in each axil. 



1 . S. concolor, Ging. Mountains of Carolina and northward, in deep 

 shades. June and July. ( Viola concolor, Pursh.) Stem 1- 2 high. Leaves 

 short-petioled. 



ORDER 15. CISTACEJS. (ROCK-ROSE FAMILY.) 



Herbs or low shrubs, with entire leaves, and regular mostly polyandrous 

 flowers. Sepals 5, persistent, the two outer ones smaller, the three inner 

 twisted in the bud. Petals mostly 5, twisted contrary to the sepals in the 

 bud, rarely wanting. Stamens few or numerous, distinct, hypogynous. 

 Anthers innate. Ovary 1-celled. Style single. Capsules 3- 5-valved, 

 bearing as many parietal placentae each in the middle of the valve, few or 

 many-seeded. Seeds orthotropous. Embryo curved, in mealy albumen. 



Synopsis. 



1. IIELIANTHEMUM. Style none. Stigma capitate. Embryo nearly annular. 



2. LECUEA. Style none. Stigmas plumose. Embryo nearly straight. 



3. HUDiONIA Style filiform Stigma minute. Embryo coiled. 



1. HELIANTHEMUM, Tourn. ROCK-ROSE. 



Petals 5, corrugated in the bud, sometimes wanting. Stigma sessile or nearly 

 so, capitate, 3-lobed. Capsule 3-valved. Embryo curved nearly into a ring. 

 Low herbs or partly shrubby plants, with fugacious yellow flowers. 



* Floivers perfect : petals conspicuous : stamens indefinite : capsule many-seeded. 



1. H. Carolinianum, Michx. Hirsute; leaves lanceolate, denticulate, 

 acute, short-petioled, the lowest obovate, crowded ; flowers large, solitary, borne 

 above the axils. Dry sandy soil, Florida to North Carolina and westward. 

 March and April. Stems 6' -12' high, ascending from a shrubby base. 

 Flowers 1' wide. 



2. H. arenicola, sp. n. Hoary ; leaves small, lanceolate, obtuse, entire, 

 with the sides revolute ; flowers solitary, or 2 - 4 in terminal umbellate clusters, 

 on slender pedicels. Drifting sands near the coast, West Florida. March and 

 April. Stems shrubby and branched at the base, all but the short (2' -6') 

 flowering stems buried in the sand. Flowers ' wide. 



* * Flowers of two kinds : the earliest as in the last section, the later ones smaller, 

 clustered, with small petals, or none, fewer stamens, and few-seeded capsules. 



3. A. COrymbosum, Michx. Tomentose, stems erect, shrubby at the 

 base ; leaves lanceolate, obtuse, entire, hoary beneath, with the sides revolute ; 

 flowers nearly sessile in a cymose cluster at the summit of the stem, the perfect 

 ones long-ped uncled ; sepals woolly. Dry sands near the coast, Florida to 

 North Carolina. April. Stems 1 high. Capsule smooth. 



