104 CRASSULACEAE 



opposite the petals. Fruit superior, consisting of free or somewhat united one to 

 many-seeded follicles. Receptacle usually with nectar-bearing scales, one behind 

 each pistil. — Genera 13 and species about 500, all continents, but most strikingly 

 and abundantly developed in South Africa. 



Geographic distribution of the family in California. — The north temperate species Rhodiola 

 rosea L. is represented in California by the var. integrifolia Jepson. It is our only strictly alpine 

 species. The greater part of our species belong to the lowest life zones, the lower and upper 

 Sonoran. Of endemic genera limited to California we have two, namely Sedella, which inhabits 

 the lower Sierra Nevada foothills and similar foothills in the Napa Range, and the peculiar Cong- 

 donia which thus far has been found only on the east slope of the Sierra Nevada in Mono County 

 at 8000 feet. This station is therefore a habitat of considerable actual elevation but ecologically 

 it represents a mountain slope strongly influenced by desert conditions. The genus Hasseanthus 

 may be considered as a derivative from Sedum in wliich the rootstock has been shortened and 

 thickened into a tuber, a resting adaptation suited to the long rainless season of its habitats 

 where the soil becomes extremely hard and desiccated. 



Our remaining genera are more or less cosmopolitan, especially Tillaea, which is limited to 

 low altitudes, the lower foothills and valley flats. The species T. erecta, a habitant of sandy 

 soils or spots of fine gravel destitute of other vegetation, is the most wide-spread species of the 

 family in California and in number of individuals vastly surpasses any other. The species of 

 Sedum occur from near sea-level to altitudes of 4000 to 7000 feet, or some of them range as high 

 as 10,000 to 12,000 feet, and are widely distributed. This genus has thus a greater altitudinal 

 range than any other genus of this family in California. The genus Echeveria is represented by 

 species of the low plains and foothills or of lower altitudes in the mountains — all of them plants 

 of dry or rocky habitats. 



Bibliog. — Baker, J. G., Genus Cotyledon (Saunders, W. W., Eefugium Botanicum l:pl. 

 56-72, — 1869). Britton, N. L., and Eose, J. N., New or Noteworthy N. Am. Crassulaceae (Bull. 

 N. Y. Bot. Gard. 3:1-45,-1903); Crassulaceae in N. Am. Fl. 22:7-74 (1905). Gunthart, A., 

 Beitrage zur Blutenbiologie der Crasulaceen (Biblio. Bot. 11^:39-62, — 1902). Nelson, A., & 

 Macbride, J. F., Cotyledon and its segregates (Bot. Gaz. 56:475-477, — 1913). 



Leaves opposite; stamens as many as the petals; diminutive annuals 1. TmLAEA. 



Leaves alternate ; stamens twice as many as the petals. 



Annuals; carpels 1-seeded, the ventral margin with a glandular fringe 2. Sedella. 



Perennials ; carpels several to many-seeded, without a ventral fringe. 



Flowers solitary; root tuberous 3. CONGDONlA. 



Flowers many, in cymes. 



Flowering stems arising from corms 4. Hasskanthtts. 



Flowering stems not arising from corms. 



Flowers imperfect; flowering stems arising from a short caudex; leaf -rosettes 



none 5. Rhodiola. 



Flowers perfect ; flowering stems arising from leaf -rosettes. 



Petals commonly spreading, at least at tip; mostly mat-like plants with 



branching rootstocks 6. Sedum. 



Petals commonly erect, often closely approximate at tip; coarse plants 

 with thick basal leaf -rosettes borne on a simple or branched 

 caudex 7. Echeveria. 



1. TILLAEA L. 



Diminutive much-branched glabrous annuals with opposite leaves. Flowers 

 minute, clustered or solitary in the leaf-axils, subsessile to long-pediceled. Sepals, 

 petals, stamens, and carpels 3 to 5 (in ours usually 4). Petals distinct, or united 

 only at the very base. Carpels distinct, erect, 1 to 12-seeded. — Species about 20, dis- 

 tributed over the entire earth. (Michael Angelo Tilli, Italian Botanist, 1655-1740.) 



Flowers solitary in the axils; petals twice the length of the sepals; carpels 8 to 10-seeded; aquatic 

 or of muddy bottoms 1. T. aquatica. 



Flowers densely clustered ia the axils; petals and sepals subequal; carpels 1 or 2-seeded; ter- 

 restrial 2. T. erecta. 



1. T. aquatica L. Water Pigmy. Stems usually decumbent and rooting at 

 the lower nodes, branched, 1 to 3 inches long; leaves linear-oblong, 2 to 3 lines long, 

 connate at base; flowers sessile or short-pedicellate; sepals % line long, twice ex- 

 ceeded by the petals; petals white, oblong, navicular; carpels 8 to 10-seeded. 



