Crassula columnaris (Stonecrop family) is a dwarf, compact, perennials or biennials succulent with with single short erect stems 1,5-6 cm high in which the grey-green to brownish leaves are rounded, fleshy, broader than long, arranged in 4 closed ranks; the leaves are incurved and so closely packed over each other as completely to hide the stem. The plant takes five to ten years to reach maturity, at which time, and if rain falls, the round body opens and a dense 'shaving brush' of cream to orange-yellow sweet-scented flowers appears. The plant is monocarpic, the individual rosette blooms only once then dies.
Branches: Short, erect, simple, (3-)15-60(-70) mm high, 3-4 mm in diameter, rarely with short axillary branches at base, completely hidden by the 8-10 leaf-pairs throughout. As Marloth aptly states, the specific name is unsuitable, as the typical plants in nature are often sunken and globular, only becoming columnar in cultivation . Leaves:Sessile, connate at the base, 4-ranked, broader than long, 10-15 mm long, 10-23 mm wide, becoming shorter upwards and forming a short tapering columnar, brownish-green, imbricate, tightly clasping and patelliform, rounded, fleshy, concave on the inner or adaxial surface and convex outwardly, lower face not keeled, tip rounded, rarely mucronate, often with membranous margins with grey-green to brown inflexed (slightly recurved) cilia. Inflorescences: Flowers are borne in a sessile, capitulum (head) directly on top of the plant (often partly hidden among the upper leaves) 10 mm tall and to 22 mm in diameter, rarely a rounded thyrse more or less hidden by leaves below, densely many flowered. Flowers: White, creamy-yellow or or tinged with red, sweetly scented. Calyx-lobes (sepals) linear to elliptic-oblong, (1.5)3-4(-5) mm long, obtuse, green to brown translucent, tips green. Corolla slender ampulliform, fused basally for 7-13 mm, white, pale yellow and often tinged red. Petals connate below, narrowly elliptic-oblong, 7-13 mm long, tapering above into a blunt, yellowish, beak 1 mm long. Stigma subsessile. Stamens with yellow to brown anthers. Filaments 1.2 - 2 mm. Anthers yellow or brown. Nectar-glands reddish.