Cheiridopsis N.E.Br., Gard. Chron

Powell, Robyn F., Boatwright, James S., Klak, Cornelia & Magee, Anthony R., 2017, Inclusion of Ihlenfeldtia and Odontophorus in Cheiridopsis (Ruschioideae: Aizoaceae) and insights into generic and subgeneric circumscription in the Conophytum clade, Botanical Journal of the Linnean Society 184 (4), pp. 457-484 : 474-477

1. Cheiridopsis N.E.Br., Gard. Chron 3: 412 (1925), emend. nov. R.F.Powell.

Type: C. rostrata .

Ihlenfeldtia H.E.K.Hartmann, Bot. Jahrb. Syst. 114 (1992), syn. nov. Type: I. excavata (L.Bolus) H.E.K.Hartmann = Cheiridopsis excavata L.Bolus.

Odontophorus N.E.Br., Gard. Chron 3: 12 (1927), syn. nov. Type: O. marlothii N.E.Br. = Cheiridopsis marlothii (N.E.Br.) R.F.Powell.

Succulent, perennial shrubs, compact to caespitose or rarely mat-forming, 50–300 mm in height. Leaves isophyllous, with subsequent leaf pairs equal along stem or heterophyllous, with subsequent leaf pairs unequal along stem; triquetrous to trigonous, sometimes rhombic, 4–150 mm long; leaf surface sometimes rough, formed by elevations above subhypodermal idioblasts or velvety; mucronate, sometimes with dentate margins or keels, epidermis papillate, with epidermal cells forming blunt papillae or trichomes; old leaves forming sheaths which usually only partially enclose the emerging leaf pair (fully enclose the emerging leaf pair in only a few species, i.e. C. meyeri , C. minor , C. namaquensis , C. peculiaris ). Flowers solitary; pedicels 30–90 mm; radiate, 30–70 mm in diameter; petaloid staminodes free, cream to yellow, rarely orange, red or magenta, sometimes magenta-suffused. Capsules woody, pedicels decumbent or erect, top flat to centrally elevated or rounded, base funnel-shaped to semi-globose; 8–18 locules; covering membranes undulate in radial direction, often with elevations in subcentral position, sometimes as prominent bulges, humps or tubes, rarely flat; closing bodies usually large, blocking at least ¾ of locule, seldom smaller, blocking at least ½ of locule; valve wings broad, equal in width to valve, or narrow, 1 / 3 width of valve, sometimes reduced to awns. Seeds flat to round, light to darker brown, smooth to papillate.

Diagnostic characters and distribution: Cheiridopsis now includes 38 species classified into three subgenera, Cheiridopsis, Aequifoliae and Odontophoroides. The genus is characterized by the old leaves that form sheaths enclosing the emerging leaf pair partially, but sometimes fully ( Fig. 8C, E ) and the large multilocular woody capsules, with 8–18 locules ( Fig. 7C, D ). Cheiridopsis spp. are also compact to caespitose, rarely mat-forming.

The diversity of the genus is centred in the Springbok-Steinkopf Region ( Fig. 6A ) and the distribution follows the winter-rainfall region of southern Africa, with few outliers outside of the winter-rainfall region. The distribution extends from southern Namibia, southwards to Langebaan and eastwards to Pofadder ( Fig. 6A ).

2. KEY TO THE SUBGENERA IN CHEIRIDOPSIS

1. Pedicel decumbent, leaves heterophyllous................. ............. 3.1. Cheiridopsis subgenus Cheiridopsis

1. Pedicel erect; leaves isophyllous...............................2

2. Capsule top rounded................................................ ...... 3.2. Cheiridopsis subgenus Odontophoroides

2. Capsule top flat to centrally elevated....................... ................ 3.3. Cheiridopsis subgenus Aequifoliae

Figures

Figure 6. Number of species per quarter degree square (QDS) (Leistner & Morris, 1976) and distribution of Cheiridopsis s.l. and subgenera (as treated in the taxonomic treatment) in the Greater Cape Floristic Region, South Africa. (A) Distribution and number of species per QDS for Cheiridopsis s.l.; (B) distribution and number of species per QDS in subgenus Cheiridopsis; (C) distribution and number of species per QDS in subgenus Odontophoroides (including species of previously recognized Odontophorus); (D) distribution and number of species per QDS in subgenus Aequifoliae (including species of previously recognized Ihlenfeldtia).

Figure 7. Capsules in Conophytum and Cheiridopsis. (A) Closed simple capsule of Conophytum wettsteinii; (B) open simple capsule of C.wettsteiniishowingthe absenceof covering membranesandclosing bodies;(C)closed multilocular capsuleof Cheiridopsis denticulata; (D) open capsule of C. denticulata showing the complex internal structures, i.e. covering membranes (cm) and closing bodies (cb), indicated by the white arrows; (E) decumbent capsules of Cheiridopsis subgenus Cheiridopsis, in Cheiridopsis namaquensis; (F) erect capsule of C. denticulata with flat to centrally elevated tops as in Cheiridopsis subgenus Aequifoliae; (G) Cheiridopsis pilosula illustrating the erect capsule with rounded tops, typical of Cheiridopsis subgenus Odontophoroides.

Figure 8. Leaf and floral characters of Cheiridopsis and Conophytum. (A) New leaves of Conophytum wettsteinii breaking out of their papery sheath, with a magenta flower; (B) partial sheath enclosing the emerging leaf pair, with a magenta flower, in Cheiridopsis glomerata; (C) leaves of Cheiridopsis meyeri completely enclosed by a white papery sheath during the dormant period, indicated by the arrow; (D) leaves of Conophytum uviforme completely enclosed in a sheath during the dormant period, indicated by the arrow; (E) Cheiridopsis purpurea with the partial sheath, common to many Cheiridopsis spp. which only encloses part of the leaves during the dormant period; (F) Cheiridopsis aspera with the prominent rough leaf surface often found in subgenus Odontophoroides.