Haworthiopsis

Gildenhuys, Sean D. & Klopper, Ronell R., 2016, A synoptic review and new infrageneric classification for the genus Haworthiopsis (Xanthorrhoeaceae: Asphodeloideae), Phytotaxa 265 (1), pp. 1-26 : 6-7

Haworthiopsis Rowley (2013a: 4)

Type:— Haworthiopsis coarctata (Haw.) Rowley (2013a: 4) ≡ Haworthia coarctata Haworth (1824: 301) = Haworthia sect. Hexangulares Uitewaal (1947a: 136) p.p. ≡ Haworthia subg. Hexangulares (Uitewaal) Bayer (1971: 160)

Detailed description: —Plants dwarf, succulent perennial herbs, solitary to proliferating, acaulescent or caulescent to ca. 400 mm long. Leaves rosulate, arranged in ranks of three or five, or spirally inserted along the length of the stem, 10–350 mm long, and 6–40 mm wide near the base. Leaf surfaces viscid in some, glabrous to scabrous, tuberculate or with ridges, tubercles concolorous to white, in some the upper surfaces windowed, lined and often reticulated. Margins smooth, tuberculate, ridged or with cartilaginous teeth. Inflorescences with few sterile bracts, usually racemose, rarely paniculate. Perianth <17 mm long, bilabiate, straight or curved, hexangular or rounded-hexangular at base, tapering to pedicel, white with brownish, pinkish or greenish hues or nerves, 3 upper tepals of the bilabiate perianth spreading to recurved, 3 lower tepals generally strongly recurved, inner and outer tepals joined at the base, rarely fused halfway, both whorls adhering. Anthers included. Style straight, included. Fruit a capsule <24 mm long, narrowly ovoid. Seed <4 mm long, usually black, to dark brown.

Identification key to the sections of Haworthiopsis (see Table 2 for a list of species included in the various sections)

- Leaves significantly arranged in a trifarious caulescent spiral or in three tiers, or in an acaulescent, quinquefarious twisted spiral; Eastern Cape and Western Cape ....................................................................................................................... H. sect. Trifariae (F)

2. Leaves with opaque to translucent windowed areas on upper surface ............................................................................................. 3

- Leaves without any windowed areas ................................................................................................................................................ 4

3. Leaves ovate-lanceolate to ovate-deltoid, upper surfaces with translucent windowed areas, leaf tips acuminate; Eastern Cape, Western Cape, Northern Cape, Free State, North-West and Namibia.............................................................................................. 5

- Leaves navicular, upper surfaces with a truncated opaque to translucent end-area, leaf tips obtuse; Eastern Cape ........................... ....................................................................................................................................................................... H. sect. Virescentes (G)

4. Plants proliferating from the base or by stolons, acaulescent to caulescent; leaves incurved, erect to spreading, variable in colour; Eastern Cape, Mpumalanga, Swaziland and KwaZulu-Natal .......................................................................................................... 6

- Plants solitary (rarely offsetting), acaulescent; leaves erect to spreading or recurved, dark green to blackish green; Eastern Cape. ....................................................................................................................................................................... H. sect. Virescentes (G)

5. Plants usually proliferous from base or by stolons, acaulescent to caulescent; upper leaf surfaces smooth; Eastern Cape, Western Cape, Northern Cape, Free State, North-West and Namibia......................................................................... H. sect. Tessellatae (E)

- Plants mostly solitary, acaulescent; upper leaf surfaces pellucid; Mpumalanga .................................... H. sect. Koelmaniorum (C)

6. Plants proliferous from the base, acaulescent to caulescent; leaves incurved, erect to occasionally spreading; Eastern Cape ....... 7

- Plants stoloniferous, acaulescent; leaves spreading; Mpumalanga, Swaziland and KwaZulu-Natal ............. H. sect. Limifoliae (D)

7. Upper leaf surfaces usually without any tubercles, lower leaf surfaces glabrous to tuberculated, leaves firm and rigid, fibrous; plants acaulescent to caulescent; inflorescences usually simple (rarely branched) ............................... H. sect. Haworthiopsis (A)

- Upper leaf surfaces sparsely to densely tuberculated, lower leaf surfaces generally tuberculated, leaves softer and with viscid strands only; plants acaulescent; inflorescences usually branched ............................................................... H. sect. Attenuatae (B)

A. Haworthiopsis sect. Haworthiopsis

≡ Haworthia sect. Coarctatae Berger (1908: 75) . Type:— Haworthiopsis coarctata (Haw.) Rowley (2013a: 4) ≡ Haworthia coarctata Haworth (1824: 301)