• Crassula exilis subs. cooperi (Regel) Toelken
• Crassula cooperi Regel

• Crassula exilis subs. cooperi (Regel) Toelken
• Crassula cooperi Regel
• Crassula bolusii Hook.f.
• Crassula exilis subs. picturata (Boom) G.D.Rowley
• Crassula picturata Boom
• Sedum regelii Kuntze

• Crassula exilis Harv.
• Crassula х justi-corderoyi H.Jacobsen & Poelln.
• Crassula petraea Schönland

• Crassula exilis subs. schmidtii (Regel) G.D.Rowley
• Crassula schmidtii Regel
• Crassula impressa N.E.Br.
• Crassula schmidtii f. alba Boom

• Crassula exilis subs. sedifolia (N.E.Br.) Toelken
• Crassula sedifolia N.E.Br.
• Crassula aurosensis Dinter
• Crassula picturata Friedrich non Boom

Description: Crassula exilis is a dwarf annual or cushion forming perennial succulent up to 100 mm high when flowering with spirally arranged rosettes and rather narrow, acute leaves. The leaves are quite variable in size and appearance. The species is distinguished by its fruits: mature follicles spreading at right angles to the axis.
Stem: Short, erect, succulent, simple or several from the same root, closely leafy, scabrous 2.5-5 cm high, 4-6 mm in diameter.
Rosettes: With leaves loosely spirally ar­ranged, old leaves remaining attached to stems.
Root system: Adventitious.
Leaves: In opposite pairs 4-6 mm apart, connate at base, in 4 ranks. Blade oblong, linear-oblanceolate to linear-elliptic, (4-)12-35(-45) mm long 1-10 mm broad, fleshy, but usually with membranous margin, rounded in cross-section or flat only on upper surface green to brown often with dark spots on upper surface. Pubescence minute, but copious, white. Tip pointed. Margin with hairs sometimes reduced to teeth and one stouter ter­minal hair per leaf.
Inflorescence: Peduncles terminal, short (c. 2,5 cm), slender, pubescent, bearing a more or less flat-topped 3–5-flowered, corymbulose cyme, leaves grad­ually becoming shorter along indistinct erect peduncle.
Flowers: Subsessile, small and cup-shaped c. 3 mm long, white or pink with petal tips spreading from midway up the corolla tube. Sepals 2-2.5 mm, ovate-oblong to triangular, blunt or pointed, margins hairy half as long as the recurved, obovate petals. Co­rolla tubular, fused basally for 0,2-0,8 mm, white or tinged more or less pink. Petals 4-4.5mm. oblong-obovate. with a projection, white, tinged pink. Styles subulate. Stamens 3-3.5 mm minute, fleshy. Anthers yellow. Flowers have musty honey-like fragrance.
Blooming season: Flowers appear in late summer through to late autumn.
Fruit (capsules): Small, spreading at right angles to flower-stalk.
Seeds: Fine dust-like.
Remarks: A complex group of garden hybrids including Crassula × justi-corderoyi and Crassula picturata hybrids, would also key out here.

Bibliography: Major references and further lectures
1) W. H. Harvey “Flora Capensis” Vol 2, 1894
2) Edgar Lamb, Brian Lamb “The Illustrated Reference on Cacti & Other Succulents” Volume 5 Blandford Press, 1978
3) Werner Rauh “The Wonderful World of Succulents: Cultivation and Description of Selected Succulent Plants Other Than Cacti” Smithsonian Institution Press, 1984
4) Doreen Court “Succulent Flora of Southern Africa” CRC Press, 01/Jun/2000
5) Stuart Max Walters “The European Garden Flora: Dicotyledons” (Part I) Cambridge University Press, 1989
6) Gordon D. Rowley “The illustrated encyclopedia of succulents” Crown Publishers, 01/Aug/1978
7) Gordon Rowley “Crassula: A Grower's Guide” Cactus & Company, 2003
8) Eggli, Urs “Illustrated Handbook of Succulent Plants, Crassulaceae Illustrated Handbook of Succulent Plants.” Springer, Berlin 2002
9) Hermann Jacobsen “Abromeitiella to Euphorbia” Blandford Press, 1960
10) Hermann Jacobsen “A handbook of succulent plants: descriptions, synonyms, and cultural details for succulents other than Cactaceae” Volume 1 Blandford Press, 1960
11) Toelken, H.R. 1997. “A revision of the genus Crassula” in southern Africa. Annals of the Bolus Herbarium 8,1-595.
12) Van Jaarsveld, E., Van Wyk, B-E. & Smith, G. “Succulents of South Africa.” Tafelberg, Cape Town. 2000
13) John Wilkes “Encyclopaedia Londinensis” Volume 5 1810
14) John Manning “Field Guide to Fynbos” Struik, 2007
15) Christopher Brickell “RHS Encyclopedia of Plants and Flowers” Dorling Kindersley Ltd, 01/set/2010
16) Otto A. Leistner “Flora of southern Africa” 1985
17) George Don “A General History of the Dichleamydeous Plants ... Arranged According to the Natural System”, Volume 3 J. G. and F. Rivington, 1834
18) Alfred Byrd Graf “Exotica, series 4 international: pictorial cyclopedia of exotic plants from tropical and near-tropic regions” Roehrs Co. Publishers, 1985
19) The National Cactus and Succulent Journal: The Official Journal of the National Cactus & Succulent Society, Volumes 31-34 National Cactus and Succulent Society, 1976
20) Dr J.P. Roux “Flora of South Africa” 2003