Hdianthemum. CIS'i'ACEJi. 189 



OuDER XIII. CISTACE^. 



By a. Gray; the geuus Lcchca revised hy Ji. L. Hoiushox. 



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

 drous 5-merous or 3-merous flowers, hypogynous, the one-celled ovary with 3 or ."> 

 parietal placentne, bearing several or many orthotropous ovule«, and seeds witii 

 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 fevy, 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 Meditrrra- 

 neau) for species, but tw^o of the four genera exclusively N. American, and 

 one genus common. CiSTUS, the Rock Rose, belongs chiefly to the Mt'<lit<rra- 

 nean region. 



* Petals 5, fugacious, opening in sunshine, caducous at iiiglitfall : ovary and cai»ulo 

 strictly one-celled, with 3 nerviform placenta;. 



1. HELIANTHEMUM. Petals broad, in all well developed flowers crumjded in tlie l.ud. 

 Stigma ca])itate 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. 



2. HUDSONIA. Petals not crumpled in the bud, cuncate or ol>ov.ite. Stamens 9 to .30. 

 Style long and filiform: stigma minute. Ovary with 2 ovules to each placenta. Sei»aLs 

 connivent in fruit, enclosing the 2-6-seeded capsule. Embryo unciuate-circinate. Foliage 

 heath-like. 



* * Petals 3, persistent : placentae on incomplete dis.sepiments. 



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

 bud, obovato or oblong, marcescent. Stamens 3 to 12 or rarely more, wlien reduced to 

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

 fimbriate-plumose. Placentae 3, broad and valve-like, each bearing a pair of erect subsesvsile 

 ovule.s, one on each side of the posterior face. Capsule glol)ose and oliscurely triangular, 

 crustaceous ; valves separating fr(nn the broad placenta*, which seem to be interior reversed 

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



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

 belongs only to Cfstns. (Composed of ?]Ato9, the sun, and uvOefjiov, flower, the 

 blossoms opening only in direct sunshine.) — The American species are e.ssci' 

 tially herbaceous or some with merely suffrutescent base, and with .nlli-rnatf 

 leaves, strictly parietal placentje, and yellow flowers. And in the rirst section 

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

 Inst. 248, t. 128; Michx. Fl. i. 307 ; Gray, Gen. 111. i. 203, i. 87. 



* Atlantic species, with dimorphous flowers; viz. the nonnal or ephemeral, w if' 

 fugacious petals, indefinite stamens, and many-see<lod capsules: and the I 



smaller, cryptopetahms or apetalous, .3-10-androus, cleistogamous. with very fen - 



and seeds : herbage liiiereous or canescent with minute and do.se jmbescrnce. especially 

 the lower face of tlie lea\cs. tlie upper face glabnUe ami green. — I/ilerumriii', Sjiach in 

 Hook. Cmp. Hot. Mag. ii. 2'.)(), & .\nn. Sci .\at. ser. 2, vi. .37(U 



