Crepidorhopalon kwaleensis I.Darbysh. & Eb.Fisch., 2019

Crepidorhopalon kwaleensis I.Darbysh. & Eb.Fisch. View in CoL , sp. nov. — Fig. 2i–k View Fig , 4 View Fig , 5 View Fig

Most similar to Crepidorhopalon whytei but differing in the anterior pair of stamens having markedly longer, slender spurs 1.8–2.4 mm long (vs spurs 0.5–1.2 mm long), in the seeds being no longer than wide and with subcircular depressions on the surface (vs seeds longer than wide, with longitudinal furrows on the surface), and in the plants being erect or decumbent (vs procumbent, scrambling, trailing or at most weakly decumbent in C. whytei ). Also potentially confused with C. hepperi Eb.Fisch. but again differing in the longer and more slender staminal spurs (these 0.5–0.7 mm long in C. hepperi ), the differing seeds (those of C. hepperi similar to C. whytei but more angular and with more conspicuous minute transverse furrows perpendicular to the longitudinal furrows – Fig. 2 View Fig ), and in having usually more broadly ovate leaves with length: width ratio 0.9–1.4: 1 (vs leaves ovate to lanceolate, length: width ratio 1.35–3.4(–4.9): 1 in C. hepperi ). — Type: Luke 3796 (holo K; iso EA [not located], MO [not seen], US [not seen]), Kenya, Kwale County, Majoreni area, 5 km NE, fl. & fr. 18 Aug. 1993.

Etymology. Crepidorhopalon kwaleensis is named after Kwale County of

Kenya, where this species is endemic.

Lindernia whytei View in CoL sensu auct.: Luke (2005) 90; Philcox & Ghazanfar (2008) 70, p.p. quoad Drummond & Hemsley 4007.

Lindernia hepperi sensu Philcox & Ghazanfar (2008) View in CoL 72, p.p. quoad spec. ex Kenya.

Annual (possibly sometimes short-lived perennial) herb, with one to few stems from a small rootstock, erect or becoming scrambling or trailing, up to 20 – 40 cm long, branching in proximal half; stems markedly 4-angular, winged along the angles, proximal portions of stems pilose with ± numerous pale multicellular eglandular hairs 0.3–1 mm long, sometimes with few interspersed glandular hairs, hairs becoming more sparse distally, fertile portions of stems (raceme rachis) ± glabrous except for inconspicuous sessile orange glands; internodes of fertile leafy stems 16–44(–90) mm long when mature. Leaves sessile, broadly ovate, 12.5–18 by 9–16 mm, base rounded or subcordate, margin with 3–5 minute teeth along each margin, apex acute, attenuate or obtuse; primary venation palmate, with 5 or 7 main veins from base; ± sparsely eglandular pilose on margin and main veins beneath, surfaces also with sunken glands drying brown, visible on lower surface. Flowers held in a lax terminal raceme, each inflorescence node singleflowered; proximal-most pair of bracts ovate to suborbicular and acuminate, 3.8–7.5 by 2.2–6 mm, rapidly reducing upwards where lanceolate or linear-lanceolate, 1.5–2.7 by 0.3–0.8 mm; bracteoles absent; pedicels 1.5–2.8 mm long, glabrous. Calyx 3.7–5.5 mm long, lobes lanceolate, somewhat unequal in length, longest lobes 2 – 4 mm long, apices can become divergent at maturity, 5-veined, hyaline between the veins, surfaces glabrous. Corolla (8–) 10.5–12 mm long, purple, lower lip with white patches in the mouth, external surface glandular-puberulous; tube 5.2–6 mm long, cylindrical, ± 1.5 mm wide centrally, internal surface with 4 lines of subsessile glands in proximal half; upper lip ovate, (2–) 2.5–4.3 mm long, apex slightly emarginate, internal surface with minute glands; lower lip (3.5–) 5–6 mm long, 3-lobed, median lobe rounded-obovate, 3–3.5 mm long, lateral lobes elliptic-obovate, 2.3–3.5 mm long, margins of lobes somewhat irregular, bosses on palate of lower lip with blunt-tipped multicellular hairs. Stamens 4, ventral stamens spurred, spurs linear-clavate, 1.8–2.4 mm long, apex papillate, filaments above spurred portion ± 4 mm long; posterior stamens with filaments ± 2 mm long; anthers of the two pairs of stamens adhering, thecae 0.45–0.7 mm long. Ovary not seen; style ± 4.5 mm long; stigma fan-shaped and minutely fringed. Capsule narrowly ellipsoid to ovoid with a gradually tapered apex, green-brown, longer than calyx, 5 –9 mm long; seeds sub-square in face view and circular in lateral view, ± 0.4–0.5 mm diam, with a row of subcircular depressions and with a marked longitudinal furrow on the posterior side.

Distribution & Ecology — Crepidorhopalon kwaleensis is known only from the coastal lowlands of southeast Kenya in Kwale County. It occurs in seepage areas and pools in grassland, palm swamps and grassland along forest margins, at 5–230 m elevation. At one site, it was found growing along the margin of a pond used by mammals as a watering hole ( Drummond & Hemsley 4007).

Additional specimens seen. KENYA, Mwasangombe Forest , 15 miles SW of Kwale, fl. & fr. 27 Aug. 1953, Drummond & Hemsley 4007 ( K) ; Kwale County, Gazi village N, fl. & fr. 12 Oct. 1991, Luke 2899 ( EA [not located], K); near Lunguma, fl. & imm. fr. 20 Aug. 1994, Luke & Gray 4061 ( EA [not located], K); Majoreni area , 5 km NE, fl. & fr. 18 Aug. 1993, Luke 3796 ( EA [not located], K); Ramisi-Lungalunga Rd before Majoreni turn-off, fl. 20 Dec. 2018, Luke et al. 18735 ( EA) .

Conservation — Based on the occurrence records cited above and two additional sight records (Q.L.), this species has an EOO of 691 km 2 and an AOO of 28 km 2. The area in which most of the localities are found (near Majoreni) is undergoing rapid habitat conversion to sugar plantations and maize fields (see Fig. 5d View Fig ), with some sub-populations almost certainly having been lost.The forest patch that adjoined the most northern record (Kaya Lunguma) has been destroyed. There is only one locality inside a protected area (Mwasagombe Forest, now believed to be inside the Shimba Hills National Reserve) but it has not been recollected there since 1953. With four threat-defined locations identified, this species is assessed as Endangered under criterion B – EN B1ab(i,ii,iii,iv,v) + B2ab(i,ii,iii,iv,v).

Notes — This species is most easily recognised by the combination of the long slender spurs on the anterior pair of stamens, longer than in the other species of the C. whytei complex, and in the striking seeds that are no longer than wide and with subcircular depressions, rather than ± longer than wide and with longitudinal furrows on the surface in other members of this group (all species have a more marked longitudinal furrow on the posterior side). It is otherwise similar to forms of C. whytei that have a racemose inflorescence due to the bracts being markedly reduced in relation to the cauline leaves, but the growth habit is more erect or decumbent than in C. whytei where the stems are trailing.

In the ‘Flora of Tropical East Africa’ account of Lindernia ( Philcox & Ghazanfar 2008) , material here assigned to this new taxon was treated under two different species – L. whytei and L. hepperi . Crepidorhopalon hepperi is easily separated from C. whytei due to its more erect, short, much-branched habit, narrower leaves, smaller flowers and calyces with the lobes usually shorter than the tube. However, C. kwaleensis does superficially look somewhat intermediate between these two species, but clearly differs from both in the stamen and seed characters mentioned above. It additionally differs from C. hepperi in having broader leaves; although the leaf shape in C. hepperi is somewhat variable, it typically has lanceolate or more narrowly ovate leaves.

The coastal lowlands of southeast Kenya are known for their botanical interest, with a variety of endemic and range-restricted species. These include species restricted to similar habitats to C. kwaleensis . For example, the pteridophyte Marsilea fadeniana Launert is known only from seasonal waterholes and dry riverbeds around Kwale ( Launert 2003), while in the Cyperaceae , Cyperus boreobellus Lye is restricted to damp soils over rock and small pools in the Kwale region and Bulbostylis afroorientalis (Lye) R.W.Haines is known with certainty only from the seasonally wet grasslands of this region ( Hoenselaar et al. 2010).