Heliantheinuin. CIST ACE JE. 189 



Oeder XIII. CISTACE^. 



By a. Gray ; the genus Lechea revised by B. L. Eobinson. 



Shrubby or nearly herbaceous plants ; with regular and prevailingly polyan- 

 drous 5-nierous or 3-merous flowers, hypogynous, the one-celled ovary with 3 or 5 

 parietal placentje, bearing several or many orthotropous ovules, and seeds with 

 an embryo curved or coiled in the copious albumen. Calyx and corolla convo- 

 lute in the bud, usually turned opposite ways, or sometimes imbricated. Sepals 

 5, two wholly external, much smaller and bract-like (rather to be regarded as 

 bracts), persistent. Petals 5 or 3. Stamens not rarely few, sometimes def- 

 initely so. Style single or none : stigmas either united or separate. Capsule 

 loculicidally 3-5-valved. Leaves opposite or alternate, penniveined, entire, 

 with or without small stipules. — Largely of the Old World (and Mediterra- 

 nean) for species, but two of the four genera exclusively N. American, and 

 one genus common. CiSTus, the Rock Rose, belongs chiefly to the Mediterra- 

 nean region. 



# Petals 5, fugacious, opening in sunshine, caducous at nightfall ; ovary and capsule 

 strictly one-celled, with 3 nerviform placeutse. 



1. HELIANTHEMUM. Petals broad, in all well developed flowers crumpled in the bud. 



Stigma capitate or cristate and 3-lobed, in ours sessile or nearly so on the ovary. Ovules 



few or numerous, on long funiculi. Embryo much curved or coiled. 

 S. HUDSONIA. Petals not crumpled in the bud, cuneate or obovate. Stamens 9 to 30. 



Style long and filiform : stigma minute. Ovary with 2 ovules to each placenta. Sepals 



conuivent in fruit, enclosing the 2-6-seeded capsule. Embryo uuciuate-circinate. Poliage 



heath-like. 



* * Petals 3, persistent : placentae on incomplete dissepiments. 



3. LECHEA. Petals alternate with the 3 proper sepals, not longer than they, plane in the 

 bud, obovate or oblong, marcescent. Stamens 3 to 12 or rarely more, when reduced to 

 tliree opposite the petals. Ovary short-stipitate : style very short or none : stigmas 3, 

 fi^briate-pluraose. Placentae 3, broad and valve-like, each bearing a pair of erect sul)sessi]e 

 ovules, one on each side of the posterior face. Capsule globose and obscurely triangular, 

 crustaceous ; valves separating from the broad placenta3, which seem to be interior reversed 

 valves. Embryo slender, arcuate or more curved in the hard albumen. 



1. HELIANTHEMUM, Tourn. Rock Rose, but the name properly 

 belongs only to Cistus. (Composed of 17X10?, the sun, and av6efxov, flower, the 

 blossoms opening only in direct sunshine.) — The American species are essen- 

 tially herbaceous or some with merely suffrutescent base, and with alternate 

 leaves, strictly parietal placentae, and yellow flowers. And in the first section 

 there is a second kind of flower, more or less diminutive and cleistogamous. — 

 Tust. 248, t. 128 ; Michx. Fl. i. 307 ; Gray, Gen. III. i. 203, t. 87. 



* Atlantic species, with dimorphous flowers ; viz. the normal or ephemeral, with 5 large 

 fugacious petals, indefinite stamens, and many-seeded capsules ; and the Lecheoid, 

 smaller, cryptopetalous or apetalous, 3-10-androus, cleistogamous, with very few ovules 

 and seeds: herbage cinereous or canescent with minute and close pubescence, especially 

 the lower face of the leaves, the upper face glabrate and green. — Heteromeris, Spach in 

 Hook. Comp. Bot. Mag. ii. 290, & Ann. Sci. Nat. ser. 2, vi. 370. 



