204 CISTACE2E. 



cending filiform funiculi, numerous or few. — In the section 

 Heteromeris, there are produced, in the course of the season, 

 clusters of smaller flowers, with petals which do not exceed 

 the calyx and seldom or never expand, or else are apeta- 

 lous or tripetalous, 3— 10-androus, and few-ovuled. 



Capsule chartaceous or cartilaginous, one-celled or half 

 three-celled, three-valved, loculicidal, the valves bearing the 

 narrow placentae upon their middle, few - many-seeded. 

 Seeds usually on slender funiculi, orthotropous, with a crus- 

 taceous testa. Embryo excentric, circumflexed or curved 

 nearly into a ring in the midst of the farinaceous albumen : 

 the slender radicle pointing to the apical micropyle : coty- 

 ledons flattish, oval, oblong, or linear. 



Herbs or suffruticose plants, usually low and branching ; 

 with alternate or partly opposite entire leaves, and yellow, 

 or sometimes white or rose-colored flowers. Stipules none 

 in American species. 



Etymology. Name formed of ifKios, the sun, and avBcpav, flower ; the 

 blossoms opening only in direct sunshine. 



Geographical Distribution. A genus of numerous species in the 

 warmer parts of Europe and especially in the Mediterranean region, and 

 with a few in similar parts of North America, nearly all of which belong to 

 Heteromeris, fipach. One species only extends northward to Canada. 



PLATE 87. Helianthemum (Heteromeris) Canadense, Michx, ; — a 

 flowering stem, early in the season, of the natural size. 



1. Diagram of the aestivation and plan of the flower. 



2. A magnified stamen, seen from the outside ; and 3, from the inside. 



4. Pistil and receptacle, magnified. 



5. Same, vertically divided, showing the numerous ovules on long funiculi, 

 fi. Transverse section, showing the slightly introflexed placenta;. 



7. A magnified pistil of one of the smaller and later flowers. 



8. Vertical section of the same, showing a solitary ovule on each placenta 1 . 



9. A capsule (and calyx) from a secondary flower, enlarged. 



10. A many-seeded capsule (and calyx) of a primary, petaliferous flower, 



enlarged to the same degree as the last. 



11. A seed, magnified. 



12. Vertical section of the same, showing the circumflexed-uncinate em- 



bryo in the albumen. 



