Psoralea diturnerae A. Bello, C.H. Stirt. & Muasya, 2015

Bello, Abubakar, Stirton, Charles H., Chimphango, Samson B. M. & Muasya, A. Muthama, 2015, Psoralea diturnerae and P. vanberkelae (Psoraleeae, Fabaceae): two new species restricted to the Core Cape Region of South Africa, PhytoKeys 44, pp. 97-107 : 98-101

Psoralea diturnerae A. Bello, C.H. Stirt. & Muasya sp. nov.

Note.

Similar to Psoralea pinnata L., but differs in being a resprouter with massed short shoots from a woody rootstock (versus much-branched reseeder with single stem in Psoralea pinnata ); grooved 3-foliolate leaves (versus 7-9-foliolate); flowers 1-3 per axil (versus 1-6).

Type.

SOUTH AFRICA. Western Cape, Oudtshoorn (-3322), Northern foothills of Outeniqua mountains, Camferskloof (-CD), 33°50'42.20"S, 22°25'8.93"E, 14 February 2014, A. Bello, A.M. Muasya, & C.H. Stirton 41 (holotype: BOL!; isotypes: K!, NBG!, PRE!).

Description.

Habit an erect shrub up to 2 m tall, resprouter. Stems 1-3, bare with bursts of seasonal shoots in upper parts, with wide internodes; brown, covered in white storied lenticels; young seasonal shoots green, glabrous, glandular; flowering shoots produced seasonally on old stems, leafy along their entire length; plants also produce numerous sterile “water” shoots up to 1 m tall giving the plant an untidy restioid appearance. Leaves 3-foliolate at the base of each seasonal shoot, reducing to 1-foliolate thereafter, glabrous; leaf size variable, larger on water shoots from the rootstock (30-45 mm long, 30-40 mm wide); petiole 2-3 mm long; terminal leaflet of flowering shoots longest (20-40 mm long), basal pair (25-35 mm long), all 1.0-1.3 mm wide; glabrous, dark green; grooved, apex acuminate, base rounded; stipules 2-3 mm long, fused for half their length to the petiole, rigid, triangular, semi-patent, those on water shoots are longer, green and arching, rapidly senescent on flowering shoots. Inflorescences axillary along the length of seasonal shoots; flowers 1-3 per axil; peduncles absent or <1 mm long, terminated by a tri-toothed cupulum; cupulum lower tooth longest, acuminate, upper two teeth fused for half their length, yellowish, rapidly senescent, 1.0-1.2 mm long; pedicels 1-2 mm long Flowers 10-12 mm long, mauve to purple and white, borne 1-3 in leaf axils along seasonal flowering shoots. Calyx 5-6 mm long, 4 mm wide, pale green; tube 4 mm long, glabrous, ribbed; teeth triangular, equal, shorter than the tube, 2 mm long, carinal tooth cucullate at apex; glandular, margins ciliate with black hairs, inner face of teeth densely black-haired. Standard petal broadly elliptic to broadly ovate, 9-10 mm long, 8-10 mm wide; claw 2-3 mm long; mauve to purple, nectar “guide” situated above the strongly developed free appendages above the apex of the claw and comprised of a basal white area from which emerges a trifid purple flash that bleeds off into purple veins. Wing petals 9-11 mm long, 4 mm wide; claw 3 mm long; locked into keel indentation but not fused with it; longer than the keel; petal sculpturing present, upper basal, comprising 7-8 transcostal parallel lamellae. Keel 6 mm long, 3 mm wide; claw 5 mm long; apex dark purple. Androecium 9 mm long; tenth stamen free; sheath split adaxially, fenestrate; nectarial ring present, 0.5 mm high. Pistil 9 mm long; ovary 1.5 mm long, stipitate, glabrous but sparsely covered near distal end in curved stalked glands; ovules 1; style thickened at point of flexure, height of curvature 2 mm; stigma erect, penicillate. Fruits unknown. Seeds unknown (Fig. 1, Plate 1).

Habitat.

This species occurs in a small area of arid fynbos on the acidic lithosol soils (Glenrosa and Mispah forms) of North Outeniqua Sandstone Fynbos vegetation (FFs 18; Rebelo et al. 2006). The plant grows along streams or near water in the valley bottom, but is also found higher up the lower slopes along seepages.

Flowering time.

December to February.

Altitude.

Known from 620-667 m.

Distribution.

Psoralea diturnerae is narrowly endemic to the northern slopes of the Outeniqua mountains in the Camferskloof area, George, Western Cape Province of South Africa (Fig. 3). Unlike other species of Psoralea (e.g. Psoralea odoratissima Jacq., Psoralea pinnata L., and Psoralea speciosa Eckl. & Zeyh.) that are colonial, this species is occasional in the landscape across a wider area.

Etymology.

The specific epithet diturnerae honours Ms. Di Turner, ispotter (http://www.ispot.org.za/user/10170), the leader of the Outramps group of the Custodians of Rare and Endangered Wild flowers (C.R.E.W., South Africa) and her merry band of walkers who brought this species to our attention and sent us reference material and photographs. Her energy and drive has made her group the most active C.R.E.W. group in South Africa.

Conservation status.

Psoralea diturnerae is very rare and has only been found in the Camferskloof area on the northern slopes of Outeniqua mountains. So far only eight live individuals have been recorded in its habitat which is in a privately protected area but under possible threat from the nearby alien pine plantations. It is, however, possible that other individuals will emerge after the next fire as the plants we saw were old and leggy. Further surveys are being planned to find more individuals. We therefore assess this species to be Vulnerable under the South African Red List categories and criteria (VU D2, von Staden et al. 2009, IUCN 3.1, 2012a, 2012b).

Discussion.

Psoralea diturnerae is a recent discovery and is part of the Psoralea pinnata complex. It is a suffrutex with a restioid appearance of massed short shoots arising from a woody rootstock and from which emerge 1-3 long shoots that branch in their upper parts. It also has grooved 3-foliolate clasping glabrous needle-like leaves with the terminal leaflet longest. It bears rigid, triangular, semi-patent, rapidly senescent stipules, 1-3-flowered axillary inflorescences produced for long lengths of the flowering shoot and a white to purple standard petal with a white trifid central flash above the strongly developed auricles. It can also be recognised by its glabrous pale green calyx with purple flushes. Psoralea pinnata by contrast is a much-branched reseeding shrub to small tree up to 5 m tall with 7-9-foliolate linear, villoso-pubescent spreading leaves with the terminal leaflet shortest; has subulate recurved persistent stipules that become woody when leaves are shed, pale mauve or pale blue flowers borne along flowering shoots in pseudo-inflorescences, hidden within the subtending leaves, and the yellowish green, white (mostly) and black-haired calyces (Table 1 ). The species are allopatric.

Additional specimens examined.

Camferskloof, northern slopes of the Outeniqua Mountains, 33°50'56.9"S, 22°24'54.7"E (3322CD), Sandstone Fynbos, 622 m, 14 February 2014, A. Bello, C.H. Stirton & A.M. Muasya 43 (BOL).

Camferskloof, northern slopes of the Outeniqua Mountains, 33°51'07.2"S, 22°25'04.7"E (3322CD), Sandstone Fynbos, 667 m, 23 January 2013, Nicky van Berkel 1120 (BOL).