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



ORDER 13. CISTACE^E. (ROCK-ROSE FAMILY.) 



Low shrubs or herbs, with reyular floicers, distinct and hypoyynous mostly 

 indefinite stamens, a persistent calyx, a 1-celled 3 - 5-valved capsule with as 

 many parietal placentce borne on the middle of the valves, and ortliotropous 

 albuminous seeds. Sepals 5 ; the two external much smaller, bract-like, 

 or sometimes wanting ; the three others a little twisted in the bud. Pe- 

 tals 3 or 5, convolute in the opposite direction from the calyx in the bud. 

 Anthers short, innate, on slender filaments. Style single or none. Ovules 

 few or many, on slender stalks, with the orifice at the apex. Embryo 

 long and slender, straightish or curved, in mealy albumen ; cotyledons 

 narrow. Leaves simple and mostly entire, the lower usually opposite, 

 and the upper alternate. Inert plants. 



1. Helianthemiun. Petals 5, rnimplert in the bud, fugacious (or none). Stigma nearly 



sessile. Stamens and ovn'es numerous in the petal-bearing flowers. 



2. Hudsonia. Petals 5, fugacious. Stamens 9 -30. Style long and slender. Pod strictly 



1-celled, 2-6-seeded. Heath-like. 



3. Lechea. Petals 3, persistent. Stamens 3-12. Style none. Pod partly 3-celled, the 



imperfect partitions bearing broad 2-seeded placentte. 



1. HELIANTHEMUM, Tonrn. ROCK-ROSE. 



Petals 5, crumpled iii the bud, fugacious. Styles short or none in our spe- 

 cies ; stigma 3-lobed. Capsule strictly 1-celled. Embryo curved in the form 

 of ;i hook or ring. Flowers in most N. American species of two sorts, viz., 

 primary or earlier ones, with large petals, indefinitely numerous stamens, and 

 many-seeded pods; and secondary, or later ones, which are much smaller and 

 in clusters, with small petals or none, 3-10 stamens, and much smaller 3 

 few-seeded pods. The yellow flowers open only once, in sunshine, and cast 

 their petals by the next day. (Name from T^AIOS, the sun, and &vdffj.ov,j{/nn -,-.) 



1. H. Canadense, Miohx. (FROST-AVEED.) Petal-bearing flowers soli- 

 - tar i/ ; the siitall secondar y flowers clustered in the axils of the leaves, nearly ses- 

 sile ; calyx of the large flowers hairy -pubescent, of the small ones hoary, like 

 the stem and lower side of the lanceolate-oblong leaves. Sandy or gravelly 

 dry soil, Maine to Minn, and southward. June - Aug. Stems at first simple. 

 Corolla of the large flowers 1' wide, producing pods 3" long ; pods of the smaller 

 flowers not larger than a pin's head. A variety is more hoary, and with a 

 stronger tendency to multiply the minute clustered flowers. Late in autumn 

 crystals of ice shoot from the cracked bark at the root, whence the popular 

 name. 



2. H. COrymbdsum, Michx. Flowers all clustered at the summit of the 

 stem or branches, the petal-bearing ones at length on slender stalks ; calyx 

 woolly. Pine barrens, N. J. and southward along the coast. 



2. HUDSONIA, L. 



Petals 5, fugacious (lasting but a day), much larger than the calyx. Sta- 

 mens 9-30. Style long and slender; stigma minute. Pod oblong, enclosed 

 in the calyx, strictly 1-celled, with 1 or 2 seeds attached near the base of each 

 nerve-like placenta. Embryo coiled into the form of a closed hook. Bushy 



