This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
(Latin thickish; referring to the thick leaves and stems). Crassulaceae. Fleshy and leafy greenhouse shrubs or herbs, grown for the grotesque appearance of some of the kinds and also for the bloom.
Variable in habit and foliage, mostly erect; rarely annual: leaves opposite, usually sessile and often connate, fleshy, very entire and the margins sometimes cartilaginous, glabrous or pubescent or scaly: flowers usually small, white, rose or rarely yellow, commonly in cymes but sometimes capitate, usually 5-merous; calyx 5-parted, the lobes erect or spreading; petals 5, free or joined at the base, erect or spreading; stamens 5, shorter than the petals; carpels 5, many-ovuled. - Species 150 or more, mostly in S. Africa, but a few in Abyssinia and Asia. Many species have been introduced to cultivated, but only a few are actually grown outside of fanciers' collections. The rocheas sometimes pass as crassulas. See Rochea.
The genus Crassula gives the name to the order Cras-sulaceae, which contains many cultivated succulent plants, and also others of widely different habit. The order is closely related to the Saxifragaceae, but differs in having the carpels of the ovary entirely free and equal in number to the petals, but the forms pass easily into the Saxifragaceae through Francoa and Tetilla, and back again through Triactina. The genera, as usually treated, are ill defined, and certain species of Sedum cross over the lines of Crassula, Cotyledon and Sempervivum, while between Crassula and Tillaea no very clear distinction can be made.
Crassulas are greenhouse plants requiring a dry atmosphere during the resting-period. While making growth, they may be treated like other greenhouse plants in the way of watering, placing them in the lightest and airiest part of the house. The pots must be drained so that any surplus moisture will easily pass through. The soil should consist of sand, loam, broken brick, and a very small quantity of leaf-soil or thoroughly rotted cow-manure. Propagation is usually from cuttings. Some of the species, such as C. falcata, do not give much material for this purpose, and they should, therefore, be headed over and the tops put in dry sand in the spring, allowing water only when they show signs of shriveling. The cut-over plants should be encouraged to make side shoots, which may be rooted after they are large enough. (G. W. Oliver.)
Fig. 1095. Crassula quadriflda. (X 1/3)
A. Floral parts in 4's. quadrifida, Baker. Fig. 1095. Perennial: leaves oblong-spatulate, the upper ones rounder, decussate: flowers with their parts in 4's, panicled, white, tinged red. Cape.
aa. Floral parts in 5's, which is considered to be normal in the genus.
b. Leaves petioled.
Soland. Plant slender and shrubby, 1-3 ft., erect or diffused and sometimes rooting at the joints: leaves dotted, stalked, cordate-reniform, obtuse, entire, glabrous: cymes panicle-like; flowers reddish, sometimes pure white; petals free, lanceolate, spreading. Cape. Winter. - Closely allied to C. spathulata.
Thunb. Somewhat shrubby, more slender and trailing than C. cordata, decumbent, branching: leaves stalked, roundish, crenate, glabrous, shining above: corymbs panicle-like; flowers rosy or flesh-colored: petals acute. Cape. L.B.C. 4:359 as C. cordata). - Likely to be cult, as C. cordata.
bb. Leaves not petioled (or only tapering to base). c. Foliage glaucous.
Wendl. (Rochea falcdta, DC). Height 3-8 ft.: leaves grown together at the base, thick, glaucous, oblong, falcate: flowers small, numerous (50 or more), in a crimson, rarely white, dense, terminal corymb; corolla-tube 1/3in. long, as long as the limb or shorter. Cape. B.M. 2035.
cc. Foliage not glaucous.
Soland. Plant shrubby, branching, tortuous below, 1-2 ft.: leaves narrow-obovate, acutish or acuminate, narrowed and grown together at the base, glabrous, spotted along the margin: cymes panicle-like, many-flowered; flowers white, small. Cape. Winter. B.M. 1771. L.B.C. 8:735. - A free-flowering window plant of easy cultivation There is a form with variegated leaves Differs from C. arborescens in the narrower acute leaves that are more tapering at base, and in the color of the flowers
Willd. Fleshy erect shrub, reaching 8-10 ft.: leaves roundish-obovate and obtuse, tapering to base, fleshy, flat and glaucous, dotted above, the edges smooth: flowers rather large, rose-colored, in trichotomous panicled cymes. Cape. B.M. 384 (as C. Cotyledon).
C. alrosangulnea, Barbey. Erect, 12-20 in., rigid: stem reddish, branched at top: leaves aloe-like, straight or recurved, glabrous, narrowed from base to apex, often 8 in. long, rosulate and on the stem: flowers dark red, in a dense terminal many-flowered cluster. Transvaal. - C. cocinea. Linn.=Rochea coccinea. - C. congesta, N. E. Br. Only 3 1/2 in. high: leaves thick and fleshy, ovate-lanceolate: flowers numerous, densely crowded in a sessile terminal head, the petals scarcely 1/2in-long, white. S. Africa - C. conjuncta, N. E. Br. Leaves concave: flowers pure white in a compact narrow cluster. S. Africa - C. decipiens, N. E. Br. Dwarf tufted perennial: leaves densely covered with blunt papillae or nipple-like projections, fleshy, oblong: flowers very small, white, in terminal 3-branched cymes. S. Africa(?). - C. jasminea, Ker-Gawl==Rochea jasminea. - C. sedifolia, N. E. Br. Only 1-2 in. high when in bloom: leaves in small tufts at the base and 3 or 4 pairs on the flower-stems, bright green, ciliate, with red-brown spots along the margin: flowers white, 3-9 together in terminal cymes.
S. Africa - C. varidbilis, N. E. Br. Plant 3-6 in. high, branched at base: leaves in 4 rows, densely imbricated, ovate, small (1/3in- or less long), ciliate on margin: flowers white, or red outside, 5-7 in small cymes disposed in a narrow terminal panicle. S. Africa L.H.B.†