Festuca caprina var. irrasa Stapf, Fl. Cap. 7: 720. 1900.

Sylvester, Steven P., Soreng, Robert J., Sylvester, Mitsy D. P. V. & Clark, Vincent Ralph, 2020, Festuca drakensbergensis (Poaceae): A common new species in the F. caprina complex from the Drakensberg Mountain Centre of Floristic Endemism, southern Africa, with key and notes on taxa in the complex including the overlooked F. exaristata, PhytoKeys 162, pp. 45-69 : 45

Festuca caprina var. irrasa Stapf, Fl. Cap. 7: 720. 1900. Fig. 4 , Table 1

Type.

South Africa. [Eastern Cape: Grahamstown], Howison Poort, Nov 1894, H.G. Flanagan s.n. (lectotype, designated by Alexeev 1986: 1115: K (K000345259 [image!]); syntype: South Africa. East Province of Cape Colony [Eastern Cape]: Amatole Mountains, Mar 1883, J. Buchanan 37 (K (K000345260 [image!])).

Notes.

Festuca caprina var. irrasa may indeed be distinct and warrant elevating to species level. It differs from the other intravaginally branched taxa in the complex ( F. caprina var. caprina and F. caprina var. macra ) by the obviously fibrous basal sheaths and usually short-hispid or long-scabrous (prickles hair-like) lemmas, paleas and rachillas. The character of lemma, palea and rachilla pubescence sometimes varies with hispid hairs sometimes only found at the apex of some lemmas in the inflorescence. The panicle branches and pedicels are also usually densely short-hispid or long-scabrous with hooks elongating to become almost hair-like, a character not seen in the other members of the F. caprina complex, although this character also appears to vary. The variation may be due to introgressive hybridisation or lateral gene transfer between taxa, which possibly occur frequently in grasses ( Kellogg 2015; Hibdige et al. 2020; Tkach et al. 2020). This could be exemplified by how one specimen (Sylvester et al. 3547) that was collected close to both var. macra (Sylvester et al. 3538) and var. irrasa (Sylvester et al. 3542) had inflorescence characteristics of var. irrasa , but antrorsely scabrous abaxial leaf-blade surfaces like var. macra . Further work is needed to clarify the circumscription and taxonomic position of var. irrasa . Festuca drakensbergensis , described herein, also usually has fibrous basal sheaths and, although not as conspicuous as F. caprina var. irrasa , can be readily distinguished based on its extravaginal tiller branching, presence of rhizomes and smaller anther size, amongst other characters.

Festuca caprina var. irrasa is endemic to the DMC of southern Africa, being found in Lesotho and the South African Eastern Cape and KwaZulu-Natal Provinces and possibly the Free State Province (although no specimens have been verified by us). The species appears to be more common in the KwaZulu-Natal Province. During our ecological plot-based study across the Afro-alpine DMC (Sylvester et al. unpubl. data), F. caprina var. irrasa was only encountered as locally abundant ([0.5-]5-35% of 2 m × 2 m plot cover) populations in the damper southern sites of the DMC, i.e. Sehlabathebe National Park (Lesotho) and Barclays Pass (Eastern Cape, South Africa). The species was found in only 11 plots ranging from the lower elevation Afro-montane to Afro-alpine grassland transition at ca. 2250 m alt. to wet Afro-alpine tussock grasslands at ca. 2750 m alt.

Alexeev (1986: 1115) cites "(P. Linder in Fl. South Africa. manusc.): Cape Province, Grahamstown, Howisons Poort, no. 94, H.G. Flaganan (K!)" for lectotype selection. However, upon inspection of the K lectotype, the ‘94’ refers to the year of collection.

Selected specimens examined.

Lesotho. Sehlabathebe National Park, lower end of the Park on the border, 29.877593S, 29.086461E, 2606 m alt., wet Afro-alpine tussock grassland, soil damp, not grazed recently, 20 Feb 2020, S.P. Sylvester et al. 3542 (PRE, US); Sehlabathebe National Park, lower end of the Park on the border, 29.876061S, 29.086150E, 2645 m alt., gravelly slopes below basalt rock escarpment with grasses intermixed with forbs, soil damp, burned and grazed recently, 20 Feb 2020, S.P. Sylvester et al. 3547 (PRE, US). South Africa. Eastern Cape: Bastervoetpad Pass area, ca. 12 km east of Mountain Shadow Hotel on Barclay Pass, 31.172568S, 27.964747E, 2259 m alt., Afro-montane transitioning to Afro-alpine grassland under moderately-heavy grazing, 14 Feb 2020, S.P. Sylvester et al. 3512 (US); KwaZulu-Natal: Giants Castle, 10,000 ft [3048 m alt.], 8 Jan 1915, R.E. Symons 352 (PRE0023182); KwaZulu-Natal: Weenen county, top of Griffins Hill, ca. 5000 ft [1524 m alt.], sedgy banks of streamlet in highland sourveld, fairly frequent, 29 Oct 1944, J.P.H. Acocks 10740 (PRE0023178).

Figures

Figure 4. Festuca caprina var. irrasa. A Whole plant B close-up of basal sheaths showing fibres C abaxial leaf blade surface of tiller D leaf blade apex of tiller E close-up of inflorescence, showing spikelets, lateral view. A, B, E of S. P. Sylvester et al. 3512 (US) C, D of S. P. Sylvester et al. 3542 (US).