CiSTALES.] 



CISTACEiE. 



349 



Order CXXII. CISTACEiE.— Rock-Roses. 



Cisti, Jttss. Gen. 294. (1789) . — Cistoideae, Vent. Tabl. 3. 219. (1799).— Cistinese, DC. Prodr. 1.26.3. 

 (1824) — Cistaceae, Ed. Pr. IxLx. (1836) ; Endl. Gen. clxxxviii. ; Meisner, p. 8j Spach in Ann. Sc. 

 n. s. 6. 365. 



Diagnosis. — Cistal Exogens, tvith trhncrous or pentamerous Jloivers, stamem usually 00 

 and never tetradynanioiis, closed up fruit and albuminous seeds. 



Shrubs or herbaceous plants. Branches often \'iscid. Leaves entire, opposite or 

 alternate, stipulate or exstipulate, generally feather-veined, but sometimes fan-veined. 

 Racemes usually unilateral. Flowers white, yellow, or red, very fugacious. Sepals 3-5, 

 continuous with the pedicel, persistent, unequal, the three inner with a twisted isestiva- 

 tion. Petals 5, very rarely 3, hypogynous, fugitive, often crumpled in aestivation, and 

 twisted in a direction 

 contrary to that of the 

 sepals. Stamens defi- 

 nite or indefinite, hypo- 

 gynous, distinct ; an- 

 thers 2-celled, opening 

 longitudinally. Ovary 

 free, 1- or many-celled ; 

 o\'ules orthotropal,(very 

 rarely anatropal,»S/x<c/i) ; 

 style single ; stigma 

 sunple. Fi-uit capsular, 

 usually 3- or 5-valved, 

 occasionally 10-valved, 

 either 1 -celled with pa- 

 rietal placentae in the 

 axis of the valves, or 

 imperfectly 5- or 10- 

 celled with dissepiments 

 proceeding from the 

 middle of the valves, 

 and touching each other 

 in the centre. Seeds 



definite or 00. Embryo inverted, either spiral or 

 cm-ved, in the midst of mealy, or somewhat horny 

 albumen. Radicle remote from the hilum. 



These plants are perfectly distinguished from 

 Violetworts, with which they were formerly con- 

 founded, by their annular and inverted embryo ; 

 from Bixads by this last character, by their mealy 

 albumen, habit, and not having the leaves ever 

 dotted ; from Tutsans, by the latter character, and 

 the structm'e of the fruit ; they are also akin to 

 Poppyworts by the genus Dendromecon. None „. rnxLI 



of their affinities, or of others that may have been 



mentioned by other Botanists, appear, however, so strong as with Crucifers and 

 Capparids, to which then' curved embryo and parietal placentation bring the Rock Roses 

 very near. From all the Cistal AUiance they are, however, known by the presence of 

 albumen in some abundance. 



A remarkable plant, found in Asia, Africa, and South America, and named Cochlos- 

 permum, seems to offer the most highly developed form of this Order, from which it 

 differs in very httle except its habit. Botanists usually place it in the Theads, but its 

 parietal placentae, anisomerous flowers, and curved embryo lying m the midst of albu- 

 men, seem fatal objections to that association. In fact it has no resemblance to the 



Fig. CCXL.— Cistus Berthelotianus. 1. a vertical section of ovary and calyx ; 2. a seed cut through; 

 the pointed end being the true apex. 



Fig. CCXLI.— 1. a section of the ovary of Cistus Berthelotianus ; 2. calyx and divided ovary of He- 

 lianthemum canariense. — Webb. 



Fig. CCXL. 



