Pelargonium pseudosetulosum M.M.le Roux & J.C.Manning, 2022

Roux, M. Marianne Le & Manning, John C., 2022, Pelargonium pseudosetulosum (Geraniaceae), a new species in sect. Pelargonium from the Kogelberg-Kleinmond area in Western Cape Province, South Africa, Phytotaxa 531 (3), pp. 293-300 : 297

Pelargonium pseudosetulosum M.M.le Roux & J.C.Manning , sp. nov.

Diagnosis:— Pelargonium pseudosetulosum closely resembles P. setulosum in its sprawling habit and in the size and form of its flowers, but differs most obviously from it in the darkly veined petals lacking a distinct blotch at the base of the upper petals. In addition, the leaves are more rounded in outline with the apical tooth not markedly larger and sharper than the flanking teeth. The flowers of P. setulosum in contrast have distinct eyespot nectar guides on the posterior petals, and the leaves are more sharply pointed with the apical tooth larger and more acute than the flanking teeth. It may also be confused with P. columbinum , but differs by its incised or lobed leaves and five stamens (usually entire, crenate leaves and seven fertile stamens in P. pseudosetulosum ).

Type: — SOUTH AFRICA. Western Cape: Caledon, Kleinmond , above settlement at the edge of the village, (3419AC), 18 October 2014, Le Roux, Johns & Koekemoer MlR134 (holotype PRE , isotype NBG).

Sprawling, short-lived perennial herb, branches up to 0.5 m long, sparsely retrorsely setulose with short eglandular hairs mixed with glandular hairs. Stipules linear-lanceolate to lanceolate, not adnate to petiole, ca. 5 × 1 mm, glabrous adaxially and puberulous abaxially with fimbriate margins. Leaves simple, rarely somewhat lobed, cordate to suborbicular, base cordate, apex obtuse and margins crenate, green, sometimes with reddish purple petioles and veins; petioles 17–55(–65) mm long, slender; laminae 14–29 mm × 17–31 mm, appressed setulose adaxially, sparsely setulose abaxially, mainly along veins. Inflorescence axillary or leaf-opposed, 30–70(–80) mm long, pseudo-umbels each with 1 or 2 flowers; peduncles 15–45 mm long, sparsely retrorsely setulose with some glandular hairs; bracts linear, 3–4 × ca. 1 mm, glabrous adaxially, setulose abaxially; pedicels 14–21(–25) mm long. Hypanthium 4.5–8.0 mm long, brownish green, puberulous with spreading eglandular hairs mixed with glandular hairs. Sepals 5, lanceolate, somewhat acuminate, 5–8 × 1–3 mm, slightly reflexed, green to reddish green, abaxially pubescent with spreading eglandular hairs mixed with glandular hairs. Petals 5, white to pale pink with dark pink veins on all petals, spathulate to oblanceolate-oblong, posterior petals slightly asymmetrical, 12.0–13.5 × 4–5 mm, anterior petals symmetrical, ca. 11.5–12.0 × 2.0– 3.5 mm, bases cuneate, recurved during anthesis. Stamens 7 fertile stamens, 3 posterior filaments shortest, 0.5–2.5 mm long, 2 lateral filaments 3–4 mm long, 2 anterior filaments 4–5 mm long, white; staminodes 0.5–1.0 mm long; anthers light brown, 1.0– 1.5 mm long, pollen orange. Gynoecium purple; ovary 1.5–2.5 mm long; style 1–3 mm long; stigma branches 1.0– 1.5 mm long, wine-red to purple. Fruit bases of mericarps ca. 4 mm long, eglandular, tails 24–31 mm long.

Distribution:— Pelargonium pseudosetulosum is restricted to the Kleinmond-Kogelberg area at elevations below 200 m above sea level ( Fig. 3 ).

Conservation notes:— The restricted distribution range of P. pseudosetulosum partly extends into the Kogelberg Nature Reserve. This suggests that the species is not necessarily under threat, but the conservation status needs to be assessed.

Additional specimens examined (paratypes):— SOUTH AFRICA. Western Cape: Kogelberg State Forest flats near Somersfontein farm, ca. 365 m, (3418 BB), 24 September 1972, Boucher 1941 ( NBG, PRE) ; Betty’s Bay Flower Show , (3418 BD), 14 October 1973, Boucher 2424 ( NBG) ; Kogelberg Forest Reserve, end of Spinnekopneskloof Road , 1000 ft [305 m], (3418 BD), 23 October 1969, Boucher 793 ( NBG, PRE) ; Kogelberg Forest Reserve, Spinnekopneskloof , (3418 BD), 8 October 1980, Boucher 4980 ( NBG) ; Kogelberg Reserve , 500 ft [152 m], (3418 BD), 24 August 1962, Van der Merwe 1242 ( PRE) ; Kogelbaai [Kogel Bay] valley, NW slopes of Blousteenberg , plot 171/ 6, 400 ft [122 m], (3418 BD), 22 December 1969, Boucher 980 ( NBG, PRE) ; Oudeboskloof in Palmiet River Valley , (3418 BD), 30 November 1986, Vorster 2943 ( PRE) ; Palmiet River , (3418 BD), 7 November 1942, Compton 14092 ( NBG) ; Kleinmond , (3418 BD), 9 November 1941, Barker 1297 ( BOL, NBG) ; E foot of Kogelberg , (3418 BD), 16 December 1946, Esterhuysen 13339 ( BOL) .

Figures

FIGURE 3. Known distribution of Pelargonium setulosum (●) and P. pseudosetulosum (■), both species endemic to the Western Cape Province, South Africa.