Pelargonium roseopetalum E. M. Marais 2021, sp. nov.
Creators: name: Marais, Elizabeth M.
name: Roux, Anso Le
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Geraniales
Geraniaceae
Pelargonium
Pelargonium roseopetalum

description: Pelargonium roseopetalum E.M.Marais, sp. nov. (Fig. 3)   
 Diagnosis: ─The reflexed posterior petals and protruding stamens are similar to those of P. reflexipetalum but P. roseopetalum differs in the pale pink to almost white flowers and prostrate simple to ternate leaves. P. reflexipetalum has bright pink flowers and prostrate to erect pinnatisect to bipinnatisect leaves.   
 Type: ─ SOUTH AFRICA. Northern Cape: Oorlogskloof Nature Reserve (3119 AC), 12 October 2006, E. M . Marais 456 (holotype NBG!; isotypes K!, PRE!).   
 A deciduous geophyte 80–150 mm tall when in flower. Tuber: turnip-shaped, elongated, sometimes moniliform root, covered with flaking dark brown periderms, 10–35 mm long and 5–10 mm in diam. Leaves radical, rosulate, simple, seldom ternate, petiolate; lamina or main pinna ovate to cordate, 10–37 x 6–30 mm, bases usually cuneate, apices obtuse, margins entire to irregularly crenate, adaxially and abaxially sparsely covered with long and short soft hairs interspersed with long and short glandular hairs; petiole prostrate, 15–80 mm long and 1.0– 1.5 mm in diam., densely covered with long glandular hairs; stipules subulate, ciliate, ± 10 mm long, adnate to petioles with apices free. Inflorescence: scape 40–60 mm long, reddish green, densely covered with distally appressed curly hairs interspersed with long glandular hairs, branched, bearing 2–4 pseudo-umbellets with 3–4 flowers each; peduncles 75–90 mm long, pale reddish green, densely covered with distally appressed curly hairs interspersed with long glandular hairs; bracts subulate, 2.0–2.5 x 1.0 mm, abaxially densely hirsute; flower buds, flowers, and fruits erect. Pedicel ± 0.5 mm long. Hypanthium 9–13 mm long, 2.0–2.5 times the length of the sepals, pale green, densely covered with distally appressed curly hairs interspersed with long glandular hairs. Sepals 5, reflexed during anthesis, lanceolate, apices acute, 5 x 1.5–2.0 mm, bases red, apices green, margins white, abaxially densely covered with distally appressed curly hairs interspersed with long glandular hairs. Petals 5, pale pink to almost white; posterior two usually without any markings, sometimes with dark red streaks, narrowly spathulate, 11.5–12.0 x 1.5–1.7 mm, length/width ratio 6.8–8.0, claws 9 x 1.5–2.0 mm, apices truncate or emarginate, reflexed during anthesis; anterior three with dark pink V-shaped markings, spathulate, 9.0–9.5 x 1.5–2.0 mm, bases attenuate, apices rounded, patent during anthesis. Stamens: 10, basally connate, staminal column 1.5 mm long, smooth, white; perfect stamens 5, posterior filament 4 mm long, lateral two filaments 4.5 mm long, anterior two filaments 5 mm long, more or less as long as the sepals, protruding from the flower, apices of free filaments red; staminodes 2.5–3.0 mm long; anthers wine red, 1.2–1.5 mm long, pollen orange. Gynoecium: ovary 2.0– 2.5 mm long; style 0.5 mm long, wine-red; stigma branches recurved, 0.5 mm long, wine-red. Fruit: not seen, Chromosome number: unknown.   
 Flowering period: ─November.   
 Habitat: ─Growing in fynbos on soil derived from sandstone in a predominantly winter-rainfall area with an average precipitation of 300–400 mm per annum. Rain falls mainly between March and October, with an extreme variation in the duration and abundance of the rain (Snijman & Perry 1987).   
 Distribution: ─An endemic of the Oorlogskloof Nature Reserve near Nieuwoudtville in the Northern Cape Province (Fig. 1).   
 Diagnostic character: ─The reflexed posterior petals and protruding stamens are similar to those of P.reflexipetalum and P. tripalmatum. All three species have spathulate or narrowly spathulate posterior petals with reflexed apices and in all of them the anterior stamens are the same length or slightly longer than the sepals and protrude from the flower. The three species differ, however, in that P. tripalmatum has yellow flowers and large tripalmate leaves (Marais 1996), P. reflexipetalum has bright pink flowers and small pinnatisect leaves (Marais 1997a) and P. roseopetalum has pale pink to almost white flowers and prostrate, simple to ternate leaves.   
 Conservation status: ─Occurring in the conserve area of the Oorlogskloof Nature Reserve.   
 Etymology: ─The specific epithet describes the pale pink flowers.
description: Published as part of Marais, Elizabeth M. & Roux, Anso Le, 2021, Two new species of Pelargonium (Geraniaceae) from the Western and Northern Cape Provinces (South Africa) and their position within P. section Hoarea, pp. 92-100 in Phytotaxa 516 (1) on pages 96-97, DOI: 10.11646/phytotaxa.516.1.7, http://zenodo.org/record/5316608