Key to the area around Southern Africa
| 1a | Scape without flowerless bracts | 2 |
| 1b | Scape with flowerless bracts | 25 |
| 2a | Petals undivided | 3 |
| 2b | Petals divided into 3-5 lobes | 24 |
| 3a | Flowers non-resupinate; lip 3-Iobed | Holothrix majubensis |
| 3b | Flowers resupinate; lip various | 4 |
| 4a | Petals green, yellow or cream, carnose at the apices | 5 |
| 4b | Petals white, sometimes with purplish margins, membranous at apices | 18 |
| 5a | Petals linear; lip lobes short and triangular with obtuse apices | Holothrix pilosa |
| 5b | Petals broader; lip lobes various | 6 |
| 6a | Lip entire or 3-1obed | 7 |
| 6b | Lip lobes 5-7 | 13 |
| 7a | Spur longer than lip | Holothrix longicornu |
| 7b | Spur shorter than lip | 8 |
| 8a | Lip entire | Holothrix exilis |
| 8b | Lip 3 lobed | 9 |
| 9a | Lip midlobe broader than long | Holothrix brevipetala |
| 9b | Lip midlobe longer than broad | 10 |
| 10a | Hairs on scape stiff, strongly deflexed | 11 |
| 10b | Hairs on scape villose, not strongly deflexed | 12 |
| 11a | Spur c.0.5-2.5 mm long; lip side lobes up to half the length of the midlobe; Drakensberg | Holothrix thodei |
| 11b | Spur normally 1.5-4 mm long; lip lobes subequal in length; Western Cape and Eastern Cape as far as Grahamstown | Holothrix cernua |
| 12a | Spur up to 1.8 mm long | Holothrix exilis |
| 12b | Spur 2-5.5 mm long | Holothrix villosa |
| 13a | Spur 1.5-4.5 mm long; from Northern, Western and Eastern Cape; if spur only I mm long then scape with strongly reflexed hairs | 14 |
| 13b | Spur 1 - l .5 mm long; from the Drakensberg and Gauteng | 17 |
| 14a | Spur longer than lip | Holothrix longicornu |
| 14b | Spur shorter than lip | 15 |
| 15a | Base ofpetals adnate to lip; leaves glabrous | Holothrix secunda |
| 15b | Petals free from lip; leaves with hairs or squamules | 16 |
| 16a | Lip lobes usually less than 2x as long as broad | Holothrix brevipetala |
| 16b | Lip lobes linear, more than 2 x as long as broad | Holothrix cernua |
| 17a | Petals more than 5 mm long; flowering from December to April; Drakensberg | Holothrix incurva |
| 17b | Petals less than 5 mm long; flowering September to October; Gauteng | Holothrix micrantha |
| 18a | Lip lobes 5 | 19 |
| 18b | Lip lobes 7 or more, or lip serrate along margin | 20 |
| 19a | Spur circinnate; leaves uniform in colour; bascs of petals adnate to lip | Holothrix parviflora |
| 19b | Spur straight; leaves veined with white; petals free from lip | Holothrix orthoceras |
| 20a | Lip lobes 7 | 21 |
| 20b | Lip lobes more than 7, or lip serrated | 23 |
| 21a | Lip lobes broadly triangular except for the outermost lobe on either side, acute; petals tapering to an acuminate apex; occurring east of Port Elizabeth | Holothrix orthoceras |
| 21b | Lip lobes truncate or obtuse, lobes on either side of the central lobe shorter than midlobe; petal apices obtuse; occurring west of Port Elizabeth | 22 |
| 22a | Inflorescence condensed at apex of spike; spur straight | Holothrix mundii |
| 22b | Inflorescence lax; spur curved abruptly forward | Holothrix aspera |
| 23a | Outermost lip lobe on either side longer than central lobes; leaves veined with white; Eastern Cape to Northern Province | Holothrix orthoceras |
| 23b | Lobes of lip subequal, short and indefinite in number, giving lip a serrated appearance; leaves not veined with white; Eastern Cape | Holothrix macowaniana |
| 24a | Spur 1.5-2 times the length of the lip; Northern Cape and Southern Namibia | Holothrix filicornis |
| 24b | Spur as long as or shorter than the lip; 1.5x longer to equal the length of the lip; Eastern Cape, KwaZulu-Natal, Lesotho, Free State and Mpumalanga | Holothrix scopularia |
| 25a | Petals undivided | Holothrix culveri |
| 25b | Petals divided | 26 |
| 26a | Flowers dimorphic, upper flowers with much elongated petals and lip lobes | Holothrix burchellii |
| 26b | Flowers not dimorphic | 27 |
| 27a | Lip lobes hair-like; from Gauteng | Holothrix randii |
| 27b | Lip lobes filiform, carnose; Northern, Western and Eastern Cape | 28 |
| 28a | Spur half to nearly equal the length of the lip; scape with a covering of short, fine, somewhat velvety hairs | Holothrix schlechteriana |
| 28b | Spur 1/5 to 1/4 the length of the lip; scape usually glabrous or sometimes with a few short hairs towards base | Holothrix grandiflora |
World Checklist of Selected Plant Families. The Board of Trustees of the Royal Botanic Gardens, Kew. Published on the Internet; http://www.kew.org/wcsp/ accessed 05.03.2020
