Acanthopsis scullyi (S.Moore) Obermeyer (1937: 138)

Steyn, Hester M. & Van Wyk, Abraham E., 2017, Taxonomic notes on Acanthopsis (Acanthaceae, tribe Acantheae): the group with semi-dense spikes and 5 - fid bracts, Phytotaxa 324 (2), pp. 101-121 : 109-111

2. Acanthopsis scullyi (S.Moore) Obermeyer (1937: 138) ; Snijman (2013: 163) ( Figs. 1 , 3B & 5 )

Basionym:— Blepharis scullyi Moore (1901: 301) . “ Acanthus carduifolius Thunb. ά spica glabriuscula”, ms. [name written on sheet], sensu Drège 2431.

Type: — SOUTH AFRICA. Northern Cape: Namaqualand [no precise locality], Scullyi 249 (holotype BM000931147 !; isotypes BOL138596!, K000394339!, PRE0129526 -0!) .

Perennial, acaulescent herb or compact subshrub, 10–15 cm tall with very short internodes. Leaves sessile, petiole-like base with spines 1–2 mm long; lamina oblanceolate, 55–105 × 10–15(–18) mm, pubescent to villose with long, silky hairs, occasionally interspersed with long glandular hairs; apex acute, base attenuate, margin undulate, coarsely dentate-spinose, spines fine to rigid, 1–3 mm long, yellowish. Inflorescences usually lax (bract lamina overlap <30%), cylindrical, subsessile with a number of infertile bracts at the base; 80–120(–150) mm long, 8–10(–12) mm in diameter. Bracts obovate to broadly obovate, (16–) 18–22 mm long (including spines), lamina 10–12(–14) mm long, base obtuse; villose with antrorse (often spreading) long, silky hairs interspersed with short hairs and occasionally also with glandular hairs; middle and upper bracts ending in 5 primary spines, 3 central primary spines usually broadly triangular; central primary spine nearly always compound with 1 or 2 pairs of short, marginal secondary spines (prickles); lateral primary spines usually with 1 short marginal secondary spine on side facing central primary spine, occasionally also with 1 short, marginal secondary spine on opposite side; primary spines spreading in flower and fruit. Bracteoles linear, 6–8(– 9) mm long, silky-hairy, also with long, glandular hairs. Calyx with dorsal sepal lanceolate to ovate, acuminate, 12–14 mm long, silky-hairy, often also with long, glandular hairs, 5–7-veined; ventral sepal lanceolate to narrowly ovate, 11–13 mm long, silky-hairy, 5(–7)-veined; lateral sepals 8–10 mm long, densely silky-hairy especially at base. Flowers clearly decussate; corolla cream to light mauve with lilac veins, cream throat, (21–)25–31 × (8–) 9–11 mm, tube 8–10 mm long, pubescent, central lobe often square (as wide as long), not or only slightly constricted at the base, truncate to emarginate. Filaments 7–8(–10) mm long, glandular; anthers beige, 3 mm long. Style with patch of glandular hairs at the base. Capsules 8–9 × 4 mm. Seeds 4 × 2 mm.

Etymology: —The specific epithet commemorates William Charles Scully [1855–1943], a magistrate, author and collector of natural history specimens, who collected the type material somewhere in Namaqualand.

Distribution, ecology and phenology: —Known from a number of localities between Steinkopf in the north and the farm Eenkoker (Bitterfontein area) in the south ( Fig. 1 ). Acanthopsis scullyi is mainly found in sandy soil derived from granitic gneisses on hill slopes and sandy plains (elevation between 700–1400 m) in a region receiving an average of 160–370 mm of rain per year. The known distribution falls within the Namaqualand Hardeveld Bioregion ( Mucina & Rutherford 2006) in the Succulent Karoo Biome ( Rutherford & Westfall 1994, Low & Rebelo 1996, Mucina & Rutherford 2006), with the Kamiesberg locality falling in the Namaqualand Cape Shrubland Bioregion ( Mucina & Rutherford 2006) in the Fynbos Biome ( Low & Rebelo 1996, Mucina & Rutherford 2006). Specimens with flowers were collected between August and September.

Conservation status: — Acanthopsis scullyi is known from many herbarium records and is locally common. There are at least 10 known subpopulations, and it is likely that many more exist as suitable habitat is widespread across its range. Subpopulations are large and appear to be resilient to disturbance, and therefore the population is not suspected to be declining. Although it is range-restricted (EOO 1272 km ²), it is not threatened and is categorised as Least Concern according to the IUCN Red List Category and Criteria ( IUCN 2012) (L. von Staden, pers. comm.).

Additional specimens examined: — SOUTH AFRICA. Northern Cape: Namaqualand Klipkoppe. Hills around Josfontein , (2917 BC), 21 August 1985, Le Roux 3256 ( NBG) ; Namaqualand District. On dirt road between Perdewater and Eyams , NNW of Springbok (river crossing), 694 m, (2917 BC), 10 October 2015, Steyn 2134 ( PRE) ; Namaqualand District . On dirt road between Steinkopf and Concordia, 1061 m, (2917 BD), 9 October 2015, Steyn 2130 ( PRE) ; Namaqualand District. On dirt road between Bulletrap and Gladkop , NNW of Springbok, 800 m, (2917 BD), 10 October 2015, Steyn 2131 ( PRE) ; Namaqualand District. On dirt road between Bulletrap and Gladkop , NNW of Springbok, 856 m, (2917 BD), 10 October 2015, Steyn 2132 ( PRE) ; Namaqualand District. On dirt road between Bulletrap and Perdewater , NNW of Springbok, 835 m, (2917 BD), 10October 2015, Steyn 2133 ( PRE) ; Springbok, Motel 5km downhill of town, 800 m, (2917 DB), 13 July 1988, Dean 547 ( J) ; Namaqualand District. Kokerboom Motel , S of Springbok, 812 m, (2917 DB), 9 August 2013, Steyn 1911 ( PRE) ; Namaqualand District . SE of Kokerboom Motel, 813 m, (2917 DB), 8 October 2015, Steyn 2124 ( PRE) ; Namaqualand District . On road between Springbok and Spektakel Pass, 813 m, (2917 DB), 11 October 2015, Steyn 2139 ( PRE) ; Leliefontein , pass W of settlement. 30°18’44.9”S, 18°04’42.5”E, 1420 m, (3018 AC), 22 September 2001, Mucina & Santos 7257/22 ( NBG). Western Cape: Eenkokerboom, 900 ft [275 m], (3018 CC), 3 September 1897, Schlechter 11061 ( NMB, PRE, Z). Without precise locality: [Illegible] zw [zwischen] Ezelsfontein u [und] Roodeberg, 3500–4000 ft [1060–1220 m], 12 November 1830, Drège 2431, s.n. ( P) .

Notes: —The type specimen of A. scullyi is very distinct and has lax inflorescences with bracts ending in short, broadly triangular primary spines with a compound central primary spine (usually two pairs of short prickles on margin), and villose leaf and bract indumentum. However, in recent collections of the species it is clear that these characters are variable as specimens occasionally have simple or compound central primary spines (Steyn 2139) or the spines could vary between shortly triangular to almost needle-shaped. However, compound, broadly triangular spines is the norm.

Mucina & Santos 7257/22 and Drège 2431 are included in A. scullyi as they have the typical bract shape (obovate) and the latter also has antrorse, villose hairs on the bracts, but both specimens have leaves with a strigose indumentum and a distinct petiole-like base (as in A. glabra ).

Figures

FIGURE 1. Known distribution of A. glabra (○), A. scullyi (▲), A. nitida (□), A. glandulopalmata (■) A. insueta (Δ) and A. carduifolia (●). Thunberg’s route (1774) indicated in red. (for explanation see Notes under taxonomic treatment of A. carduifolia)

FIGURE 3. Comparison of floral parts, associated bracts and bracteoles (from left to right): bracts (2), bracteoles (2), calyx (4 sepals: dorsal, ventral and 2 lateral ones) and corolla with anthers.A. A. glabra, B. A. scullyi, C. A. nitida, D. A. glandulopalmata, E. A. insueta, F. A. carduifolia. Note: the bract on the left is from lower down in the same inflorescence. Scale bar = 10 mm. Vouchers:A = Steyn 1893 (PRE), B = Steyn 1911 (PRE), C = Steyn 1884 (PRE), D = Steyn 1890 (PRE), E = Steyn 1805 (PRE), F = Koekemoer 4620 (PRE).

FIGURE 5. Acanthopsis scullyi. A & B. Habit. C & D. Leaf indumentum (abaxial). E & F. Bract. G. Calyx. H. Corolla (lobes cream to pale purple; throat cream). I. Glandular hairs at base of style. J. Capsule. K. Capsule with seed. Vouchers: C = Steyn 2134 (PRE), D–K = Steyn 1911 (PRE). Photographed by: H.M. Steyn (A, C–K) and M. Koekemoer (B).