Crassula L.
Annual or perennial herbs, subshrubs or shrubs. Lvs opposite, simple, entire or sometimes crenately toothed, usually spaced along stems, often decussate, sometimes subrosulate, connate at base or free, sometimes small and scale-like. Infl. terminal or axillary, of loose or compact cymes forming a corymb or thyrse, sometimes 1-few-flowered. Fls 4-5-(12)-merous, erect or spreading in bud. Sepals free or slightly connate at base, equal. Petals free or slightly connate at base, sometimes lower part fused to form a tube, fleshy, often spreading and corolla star-like, usually white, pink or red, rarely yellow. Stamens as many as petals, in 1 whorl, free or almost so, included or exserted. Scales free, very variable in shape. Carpels free, (4)-5-(12). Seeds usually numerous, occasionally 1-few.
SYNOPSIS
The synopsis is mostly taken from Tölken, H. R., A Revision of the Genus Crassula in Southern Africa (1977).
- A. Subgen. CRASSULA.
- Lvs sessile, with hydathodes usually scattered over the surface, if hydathodes marginal then in dense rows; infl. a terminal dichasium, usually with a distinct peduncle; fls not star-like.
- 1. Sect. CRASSULA.
- Infl. a rounded or flat-topped thyrse; calyx usually < 1/2 length of corolla; corolla small, 3-7 mm long:
- perfoliata L. var. minor (Haw.) G. Rowley
- 2. Sect. KALOSANTHES.
- Infl a ± capitate thyrse; calyx c. 1/2 length of corolla; corolla large, 20-50-(60) mm long:
- 1.*coccinea
- B. Subgen. DISPOROCARPA.
- Lvs petiolate or sessile, with hydathodes usually in 1-2 rows along the margins, sometimes scattered; infl. a cluster of axillary fls, sometimes fls solitary, rarely a terminal or lateral dichasium, with or without a peduncle; fls usually star-like.
- 3. Sect. ACUTIFOLIA.
- Stems thick, fleshy, erect to almost prostrate, ± woody towards base; infl. a rounded or flat-topped thyrse; fls 5-merous; calyx < petals; corolla small, tubular:
- sarcocaulis Ecklon et C. Zeyher 5. *tetragona
- 4. Sect. ANACAMPSEROIDEAE.
- Stems rather slender to moderately thick and fleshy, erect to prostrate; infl. a terminal cyme or elongated to flat-topped thyrse, sometimes fls solitary; fls 5-merous; calyx usually < petals; corolla rather small, composed of free, patent petals:
- arborescens (Miller) Willd. 3. *multicava*pellucida4. *spathulata
- 5. Sect. GLOMERATAE.
- Stems slender, soft, delicate and scarcely succulent or wiry, erect to decumbent; infl. an axillary cyme, often with few, sometimes many, fls, and/or a terminal cymes; fls 4-5-merous; calyx from slightly < to > petals; corolla very small, composed of free or basally fused spreading petals:
- 2. *decumbens6. colorata10. manaia11. mataikonamuscosa L. 16. sieberiana18. tetramera
- 6. Sect. HELOPHYTON.
- Stems slender to filiform, soft, delicate and scarcely succulent, erect to prostrate or floating; fls solitary or occasionally few, axillary; fls 4-merous; calyx from c. 1/2-3/4 petals; corolla very small, composed of basally fused, spreading petals:
- 7. helmsii8. hunua9. kirkii12. moschata13. multicaulis14. peduncularis15. ruamahanga17. sinclairii
Key
c. 170 spp., widespread in temperate, subtropical and tropical regions, especially southern Africa. Native spp. 13, naturalised 6.
As circumscribed here Crassula includes Rochea DC. and Tillaea L. Allan (1961) treated the indigenous spp. under Tillaea, but these have now been transferred to Crassula [Druce, A. P. and Given, D. R., New Zealand J. Bot. 22: 583 (1984, publ. 1985); Druce, A. P. and Sykes, W. R., in Connor, H. E. and Edgar, E., ibid. 25 : 128 (1987)]. All the indigenous Crassula spp. are small, slender-stemmed herbs with very small, usually solitary and axillary 4-(5)-merous fls, and are thus very different to all the naturalised spp. except C. decumbens. In addition, many indigenous spp. inhabit moist or very wet places, especially around lakes and tarns where they are often submerged for part of the year.
A number of South African spp. other than those naturalised are commonly cultivated in warmer parts of N.Z. and sometimes long persist as cultivation relics, especially in old hillside gardens. The 3 most likely to occur are: C. arborescens (Miller) Willd., a much-branched shrub to c. 2 m high with punctate lvs and white or pinkish fls; C. muscosa L. var. muscosa (C. lycopodioides Lam.), very similar to a small whipcord Hebe, as well as superficially resembling Sedum liebmannianum (see below); C. perfoliata L. var. minor (Haw.) G. Rowley, nearly always known in horticulture as C. falcata H. A. Wendl., with large, thick, oblong-falcate lvs and dense, corymbose infls of numerous scarlet fls.
The treatment of naturalised Crassula is based on the studies of H. R. Tölken, particularly in Leistner, O. A. (Ed.) Fl. Southern Africa. 14, Crassulaceae (1985), and for the N.Z. spp. on unpublished data supplied by A. P. Druce.