Acanthopsis disperma-hoffmannseggiana

Steyn, Hester M. & Van Wyk, Abraham E., 2015, Taxonomic notes on the Acanthopsis disperma-hoffmannseggiana complex (Acanthaceae, tribe Acantheae), with an interim key to members of the genus, Phytotaxa 219 (1), pp. 1-26 : 7-8

Key to the species of the Acanthopsis disperma-hoffmannseggiana complex (comparison of species also supplied in Table 1)

1. Flowers with corolla tube markedly elongated,> 15 mm (usually> 25 mm) long (Richtersveld, Northern Cape, South Africa) ...... .............................................................................................................................................................................................. 1. A. tuba

- Flowers with corolla tube relatively short, up to 15 mm long ( Namibia ; Northern and Western Cape, South Africa).....................2

2. Plants glaucous (blue-green or blue-grey); leaf indumentum usually of densely packed, appressed, short hairs.............................3

- Plants various shades of dark green, but never glaucous; leaf indumentum of sparsely arranged, appressed, strigose or spreading hairs....................................................................................................................................................................................................4

3. Leaf margin undulate, coarsely dentate-spinose with long, yellowish orange spines; leaves sessile with base decurrent; corolla throat yellow (Richtersveld, Northern Cape, South Africa) ..................................................................................... 2. A. ludoviciana

- Leaf margin flat to undulate, spinose with short, fine yellow spines; leaves with petiole 3–8 mm long; corolla throat white (Sperrrgebiet, Namibia )................................................................................................................................................................. 3. A. adamanticola

4. Bract lobes with long, viscid glandular hairs 0.2–0.3(–0.4) mm long, or if from Kenhardt-Pofadder area, then usually also with silky villose indumentum (glandular hairs present but difficult to see); if glandular hairs on bracts shorter than 0.2 mm, then leaf indumentum always with spreading, glandular hairs.........................................................................................................................5

- Bract lobes without viscid glandular hairs, or if glandular hairs present, then sessile to subsessile; leaf indumentum variable, but not with spreading glandular hairs and not densely villose................................................................................................................6

5. Plants biennial/perennial subshrubs; inflorescences 9–12 mm in diameter; leaves (and inflorescences) densely villose (Bushmanland, Northern Cape, South Africa)...................................................................................................................................4. A. villosa

- Plants annual to short-lived perennial acaulescent herbs or subshrubs; inflorescences (12–)15–18(–20) mm in diameter; leaves never densely villose ( Namibia to Western Cape, South Africa)...................................................................5. A. hoffmannseggiana

6. Plants annual acaulescent herbs; inflorescences (12–)13–15(–20) mm in diameter; bract lobes almost glabrous to villose ( Namibia to Richtersveld, Northern Cape, South Africa) ............................................................................................................ 6. A. disperma

- Plants biennial/perennial acaulescent herbs (seldom subshrubs); inflorescences (8–) 10–12 mm in diameter; bract lobes villose, never glabrescent (Little Karoo, Western Cape, South Africa) ..............................................................................7. A. dispermoides