Oxalis species

Oberlander, Kenneth C., Roets, Francois & Dreyer, Ne. L., 2014, Discovery of substantial Oxalis (Oxalidaceae) diversity and endemism in an arid biodiversity hotspot, Phytotaxa 181 (2), pp. 79-95 : 83

Key to the Oxalis species of the Richtersveld National Park and Conservancy (numbering refers to placement of description in text; A = Range extensions; B = new Richtersveld taxa)

1. Flowers more than one per peduncle ............................................................................................................................................... 2.

- Flowers one per peduncle (very occasionally 2-flowered) .............................................................................................................. 8.

2. Petal lobes yellow ............................................................................................................................................................................ 3.

- Petal lobes white or pink ................................................................................................................................................................. 4.

3. Above-ground stem well-developed, or if acaulescent, then leaves not adpressed to ground; bracts uniformly small, linear ........... ............................................................................................................................................................. A1) O. copiosa / O. haedulipes

- Acaulescent; leaves in an adpressed basal rosette; bract size variable, largest often spathulate .................... B1) Oxalis rosettifolia

4. Above-ground stem unbranched ...................................................................................................................................................... 5.

- Above-ground stem branched .......................................................................................................................................................... 6.

5. Plant glabrous to sparsely hairy; peduncles at least three times longer than the petioles ....................................... B2) Oxalis nivea

- Plant densely hairy on all parts; peduncles less than twice as long as petioles ................................................ B3) Oxalis sp. nov. 1

6. Petal lobes light pink; sepal calli prominent, red or orange ......................................................................... B4) Oxalis rubricallosa

- Petal lobes white; sepal calli poorly developed or absent ............................................................................................................... 7.

7. Plant glaucous; abaxial petal margin pink; leaflets without translucent white markings at incision ................ B5) Oxalis petricola

- Plant apple green; abaxial petal margin same colour as petal lamina; leaflets with translucent white markings at incision .............. ........................................................................................................................................................................... B6) Oxalis sp. nov. 2

8. Leaflets linear, at least twice as long as broad, usually much more ................................................................................................ 9.

- Leaflet shape variable, not much longer than broad....................................................................................................................... 12.

9. Above-ground stem exserted above the ground, well-developed ................................................................................................. 10.

- Above-ground stem not exserted above ground level, or if so, then poorly developed ................................................................ 11.

10. Plant glandular-hairy; young flower buds cernuous (nodding); flowers white or yellow ........................ A2) Oxalis campylorrhiza

- Plant with simple hairs; young flower buds held straight; flowers pink ........................................................ A3) Oxalis cf. linearis

11. Plant glabrous when mature, wiry; leaflets peltately arranged around apex of petiole ............ B7) Oxalis sp. nov. 3 ‘canaliculata’

- Plant glandular-hairy when mature, soft; leaflets digitately arranged .............................................................. B8) Oxalis sp. nov. 4

12. Petioles and peduncles with downward-oriented hairs; bulb distinctly wrinkled and shrivelled .......................... A4) Oxalis obtusa

- Petioles and peduncles with erect, spreading or absent hairs; bulb not as above .......................................................................... 13.

13. Leaflets rough, not waxy, epidermal cells prominent, inflated, clearly visible ............................................................................. 14.

- Leaflets with smooth surface, glaucous; epidermal cells not prominent, inflated or clearly visible ............................................ 16.

14. Plant glabrous; bulb clearly angled, square in cross-section; flowers white ................................................... A5) Oxalis pocockiae

- Plant hairy; bulb not angled; flowers yellow ................................................................................................................................. 15.

15. Petioles and peduncles densely hairy; corolla tube narrow, deep; bulb> 3 cm, smooth and without convex swellings (non-bullulate); tunics blackish .......................................................................................................................................... A6) Oxalis foveolata

- Petioles and peduncles sparsely hairy; corolla tube trumpet-shaped, shallow; bulb <3 cm, with convex swellings (bullulate); tunics brownish .................................................................................................................................................. A7) Oxalis bullulata

16. Leaflets massive, more than 2 cm broad, occasionally rolled into a cylinder ............................. B9) Oxalis sp. nov. 5 ‘magnifolia’

- Leaflets smaller, less than 2 cm broad, always flat ....................................................................................................................... 17.

17. Sepals acute, 3 mm long or less; leaflets marked with distinct brown spots/streaks on lower surface ..........................................18.

- Sepals obtuse, more than 3 mm long; leaflets without spots/streaks on lower surface ................................................................. 19.

18. Petioles half as thick as peduncles; corolla tube deep, slightly constricted at mouth, slightly inflated below mouth (flask-shaped) ....................................................................................................................................................................... A8) Oxalis inconspicua

- Petioles twice as thick as peduncles; corolla tube shallow, widening consistently to mouth (trumpet-shaped) ................................. ......................................................................................................................................................................... B10) Oxalis sp. nov. 6

19. Bulb deeper than 10 cm; leaflet abaxial surface deep maroon red; sepals notched or uneven .................. A9) Oxalis psammophila

- Bulb shallower than 10 cm; leaflet abaxial surface green, sepals smoothly obtuse .................................... A10) Oxalis sonderiana