Acanthopsis spathularis (Nees) Schinz (1890: 201)

Steyn, Hester M. & Van Wyk, Abraham E., 2016, Taxonomic notes on the shrublet species of Acanthopsis (Acanthaceae, tribe Acantheae), with two new species from South Africa, Phytotaxa 244 (2), pp. 145-160 : 150-154

1. Acanthopsis spathularis (Nees) Schinz (1890: 201) ; Clarke (1901: 35); Snijman (2013: 163) ( Figs. 1 , 3A , 4 & 7A, a )

Type: —[ SOUTH AFRICA, Northern Cape:] [ Illegible ] zum Goedemanskraal und Kaus 2000–2500 ft [600–750 m], 8 September 1830, Drège 2440 (lectotype P04426153! designated here; iso-lectotype S-G-47 scan!) .

Acanthus spathularis E.Mey. in Drège (1843: 91, 161), nom. nud.

Acanthodium spathulare Nees in Candolle (1847: 277).

Blepharis spathularis (Nees) Anderson (1864: 35) .

Perennial shrublet, 30–40 cm tall. Stems (young) beige to brown, ribbed, hirsute with deflexed short, white hairs; internodes (6–) 10–15 mm long. Leaves lanceolate, 20–25(–40) × 7(–8) mm, glaucous with appressed, densely packed short hairs; margin coarsely dentate-spinose, spines fine to rigid, 2–4(–6) mm long, orange-brown; base attenuate, decurrent with long spines (4–6 mm long). Inflorescences globose to cylindrical, subsessile to shortly pedunculate, with 1 (or 2) pairs of peduncular bracts; ca. 25–30(–35) mm long, (10–)13–15(–20) mm in diameter, peduncle (6–) 10– 15 mm long, hirsute to pubescent with deflexed to spreading short, white hairs. Bracts hemispherical to broadly wedge-shaped, (20–) 30–40 mm long, base 8–12 mm long, ending in 5 primary spines; middle to upper bracts with spatulate central primary spine, usually simple or with 1 (or 2) marginal secondary spines; lateral primary spines simple, often slightly spatulate, occasionally with 1 basal secondary spine; primary spines of lower bracts widely spreading in flower and fruit; bract base and spines with deflexed to appressed short hairs and some scattered subsessile glandular hairs, bract base becoming villose in upper bracts. Bracteoles linear, 7–9 mm long, silky hairy especially towards tip. Calyx with dorsal sepal ovate to obovate, acuminate to cuspidate, 10(–11) mm long, silky hairy adaxially, silky hairy (villose) abaxially especially towards tip, 7–9-veined from base; ventral sepal ovate, 10(–11) mm long, silky hairy adaxially, silky hairy (villose) abaxially especially towards tip, 7-veined from base; lateral sepals lanceolate, ending in spinous tip, broader at base, 9 mm long, silky hairy. Flowers purple with darker veins and white throat; corolla 21–23 × 12–14 mm, tube (5–) 7 mm long, pubescent; central lobe wider than long, constricted at the base, truncate. Stamens with purple anthers, 3 mm long; filaments (4–) 5 mm long, glandular. Style with patch of glandular hairs at the base. Capsules and seeds not seen.

Etymology: —The epithet spathularis refers to the spatulate (spoon-shaped) central primary spine of the middle to upper bracts.

Distribution, ecology and phenology: —Endemic to South Africa; known from the type locality (probably in Springbok area, Northern Cape —precise locality unknown) and rediscovered in October 2015 in two locations in the mountains south-west of the Anenous Pass ( Fig. 1 ). It grows in sandy soils on mountain summits at elevations of 550– 650 m in areas receiving a mean annual rainfall (mainly in winter) of 150–200 mm. Its distribution range falls within the ecotone between the Namaqualand Hardeveld and Richtersveld Bioregions ( Mucina & Rutherford 2006), within the Succulent Karoo Biome ( Rutherford & Westfall 1994, Low & Rebelo 1996, Mucina & Rutherford 2006). The known populations falls within the Gariep Centre of Endemism ( Van Wyk & Smith 2001). Flowering time: September and October.

Notes: —The author citation “(E.Mey.) Schinz” ( IPNI 2015, Welman 2003, Snijman 2013) is incorrect. Although the name Acanthus spathularis was first applied by E.H.F. Meyer in Drège (1843) to a Drège collection (Drège s.n.) (probably Drège 2440 —see P04426153), it was published without a description and hence is a nomen nudum. Nees in Candolle (1847) validly published the name Acanthodium spathulare Nees with Acanthus spathularis as a synonym. The correct author citation of the name Acanthopsis spathularis is therefore (Nees) Schinz.

Acanthopsis spathularis appears to be most closely related to A. horrida from which it differs in having short inflorescences with a spatulate central primary spine in the middle to upper bracts (vs. longer inflorescences with an ensiform central primary spine) and by having relatively small leaves with coarsely dentate-spinose margins and fine to rigid spines (vs. larger leaves with very coarsely dentate-spinose margins and rigid spines). Although A. spathularis also shares a 5-spined bract with A. erosa , it can easily be distinguished from the latter by the short inflorescences with spatulate central, primary spines. For more differences see Table 1.

Conservation status: — Acanthopsis spathularis is currently only known from two subpopulations (the exact location of the type locality remains unknown) and therefore has a very restricted distribution range. However, this specific area is botanically poorly explored and it is highly likely that other populations could be found in similar habitats in the area. The specific populations are relatively small (± 100 plants per locality) but are looking healthy with no sign of negative impact at present. However, this area is used for communal grazing and overgrazing could rapidly change the threat status, hence it is categorised as Vulnerable D2 (L. von Staden, pers. comm. 2015).

Additional specimens examined: — SOUTH AFRICA. Northern Cape: Namaqualand District , on track SW of Steinkopf, 616 m, (2917BC), 10 October 2015, Steyn 2135 ( NBG!, PRE!) ; Namaqualand District , on track SW of Steinkopf, 555 m, (2917BC), 10 October 2015, Steyn 2136 ( KMG!, PRE!) .

2. Acanthopsis horrida (Nees) Nees in Candolle (1847: 278); Anderson (1864: 36); Schinz (1890: 201); Clarke (1901: 35); Snijman (2013: 162) ( Figs. 1 , 3B & 7B, b )

Type: —[ SOUTH AFRICA. Northern Cape:] Namaqualand, Reise nach Kamiesberg , Boschmanland bis zur Mundung des Garip , November , Zeyher 73.11 (lectotype S09-4255 scan! designated here; iso-lectotypes P04426156!, P04426158!, P04426161!, SAM in NBG!, S-G-42 scan!, TCD scan!, Z scan!) .

Dilivaria horrida Nees in Von Schlechtendal (1841: 363).

Acanthodium plumosum E.Mey. in Drège (1837: 2; 1843: 67, 161), nom. nud.

Acanthodium plumulosum E.Mey. sensu Nees in Candolle (1847: 278), (orth. var. et nom. nud.).

Acanthopsis trispina Clarke (1901: 35) , syn. nov. Type:—[ SOUTH AFRICA] Cape [without precise locality], Mund s.n. (holotype K!).

Perenial shrublet, 20–50 cm tall. Stems brown (rarely maroon), ribbed, hirsute with deflexed to spreading short, white hairs; internodes (8–)10–15(–20) mm long. Leaves lanceolate to linear, 35–45(–60) × 8–10(–11) mm, indumentum variable, usually almost glabrous to strigose with appressed short hairs interspersed with subsessile glandular hairs; margin undulate, very coarsely dentate-spinose, spines rigid, 4–7 mm long, yellow; base attenuate, decurrent. Inflorescences globose to cylindrical or conical, sessile to subsessile with short peduncle (nearly always <5 mm long); (25–) 40–60 mm long, 9–12(–15) mm in diameter. Bracts ovate, obovate to wedge-shaped, 14–20(–26) mm long, base 4–8(–14) mm long; middle to upper bracts ending in 5(–7) primary spines; central primary spine usually compound with 2(or 3) pairs of marginal secondary spines, lateral spines with 1 (or 2) basal secondary spines and 1–3(–5) marginal secondary spines; lateral primary spines slightly longer than central primary spine or same length; spines spreading, rarely recurved in fruit; bract base usually hirsute to pubescent with deflexed to spreading short hairs, often villose with long, silky hairs; spines almost glabrous to pubescent, with some subsessile glandular hairs in centre, usually with long, silky hairs on margin. Bracteoles lanceolate to linear, 7–9 mm long, silky hairy. Calyx tips tinged brown or maroon; dorsal sepal ovate, cuspidate, 10–14 mm long, silky hairy especially adaxially, often with short, spreading hairs abaxially, 7–9-veined from base; ventral sepal ovate, 10–11 mm long, silky hairy especially adaxially, often with short, spreading hairs abaxially, 5–7-veined from base; lateral sepals lanceolate, 7–8 mm long, silky hairy especially at base and along margins. Flowers blue to blue-purple with white throat; corolla 23–29(–33) × 11–15(–18) mm, tube 8–10 mm long, pubescent; central lobe usually as long as wide, constricted at base, truncate to emarginate. Stamens with purple-black anthers, 2(–3) mm long; filaments 4–5(–7) mm long, glandular. Style with patch of glandular hairs at base. Capsules ovate, flattened, glabrous, shiny, 8 × 4 mm, 2-seeded. Seeds 5 × 4 mm, covered with long white hygroscopic hairs.

Etymology: —The epithet horrida refers to the spiny appearance of the plant, horrida being the Latin for prickly.

Distribution, ecology and phenology: — Acanthopsis horrida is endemic to South Africa and is mainly found in the Kamiesberg area and on the sandy coastal plains near Hondeklip Bay, with a disjunct presence in the Richtersveld ( Fig. 1 ). It grows in areas receiving a mean annual rainfall (mainly in winter) of 100–250 mm (Kamiesberg) and <50 mm (Richtersveld). Its distribution range falls within the Namaqualand Hardeveld and Richtersveld Bioregions ( Mucina & Rutherford 2006) respectively, within the Succulent Karoo Biome ( Rutherford & Westfall 1994, Low & Rebelo 1996, Mucina & Rutherford 2006). Acanthopsis horrida is found at elevations between 170 and 1200 m and is mainly associated with quartzitic sand and soils derived from granitic gneisses. The Richtersveld population falls within the Gariep Centre of Endemism ( Van Wyk & Smith 2001). Flowering time: July to September.

Notes: —Specimens from various herbaria were encoded as being collected by Ecklon or Ecklon & Zeyher ( JSTOR 2015). Glen and Germishuizen (2010) stated that “it may be difficult to determine whether a given specimen is collected by Ecklon, Zeyher, or both…” These two collectors added to the confusion by having used different methods of numbering. Some specimens have a Zeyher collecting number, others have text from Ecklon and Zeyher’s Enumeratio and often a specimen would have a double number e.g. 73.11 (see Type collection) ( Glen & Germishuizen 2010). This double number consists of a reference to the locality where the plant was collected (first part, 73) and the month of collection (second part, 11). The Dilivaria horrida specimens were most probably collected by Zeyher, as Ecklon did not collect in Namaqualand ( Glen & Germishuizen 2010). According to Drège (1847) the type locality for Zeyher 73.11 is “Namaqualand, Reise nach Kamiesberg Boschmanland bis zur Mundung des Garip”.

Despite the disjunct distribution and differences in preferred geology, climate (e.g. amount of rainfall) and morphology (shorter internodes and less hairy bracts), the specimens from the Richtersveld are provisionally included in A. horrida . Further fieldwork might lead to the recognition of infraspecific taxa in future.

Clarke (1901) described A. trispina from a single collection (Mund s.n.) without a specific locality. According to Clarke (1901), A. trispina differs from A. spathularis in having cylindrical spikes and from A. horrida in having sparingly hairy bracts ending in three primary spines as opposed to five. However, Mund s.n. is a poor specimen with most of the bracts old and damaged. When the type specimens of A. trispina and A. horrida were critically studied, it became clear that these two names apply to the same taxon and A. trispina (the younger name) is therefore considered to be a synonym of A. horrida .

Conservation status: — Acanthopsis horrida is a widespread species and is classified as Least Concern ( IUCN 2001) (L. von Staden, pers. comm. 2015).

Additional specimens examined: — SOUTH AFRICA. Northern Cape: Richtersveld National Park, Sebraskloof , SW of Gannakouriep Wilderness Camp, 464 m, (2817AC), 29 June 2013, Steyn 1902 ( PRE!) ; Richtersveld National Park, Sebraskloof , SW of Gannakouriep Wilderness Camp, 446 m, (2817AC), 2 July 2013, Steyn 1903 ( PRE!) ; Richtersveld, Bababaddens, inside gorge below Bababaddens , (2817AC), 8 February 2014, Van Wyk s.n. ( PRE!) ; Little Namaqualand, near top Rattelpoort , (2917BD), 30 December 1909, Pearson 2961 ( BOL!) ; Namaqualand, Buffels River Kloof , (2917DB), September 1945, Lewis 1739 (SAM in NBG!) ; Little Namaqualand. Copperberg , (2917DB), October 1926, Pillans 5674 ( BOL!) ; Namaqualand, Springbok Dist., Hester Malan Wild Flower Reserve , mountain range SE of houses, (2917DB), 29 May 1975, Rösch & Le Roux 1204 ( PRE!, PRU!) ; Namaqualand District, Buffels River , (2917DC), 6 September 1945, Compton 17247 ( NBG!) ; Namaqualand District, Namaqua National Park, on 4x4 track from Kykokeis to Kookfontein , 389 m, (2917DC), 12 August 2009, Steyn 1564 ( PRE!) ; Namaqualand District, Wildeperdehoek Pass , 562 m, (2917DC), 13 August 2009, Steyn 1567 ( PRE!) ; Namaqualand District, Wildeperdehoek Pass , 492 m, (2917DC), 11 August 2011, Steyn 1858 ( PRE!) ; Namaqualand Dist. Mi[e]sklip, (2917DD), 25 August 1941, Compton 11529 ( NBG!) ; Namaqualand, Droëdap , (2917DD), 27 August 1941, Compton 11561 ( NBG!) ; Little Namaqualand, Mesklip , (2917DD), 24 August 1941, Esterhuysen 5833 ( BOL!) ; Namaqualand District, Farm Theunis se dam, 560 m, (2917DD), 2 September 2010, Steyn 1770 ( PRE!) ; Namaqualand, Springbok area, Goegap Nature Reserve , (2918CA), August 2006, Broodryk 145 ( PRU!) ; Namaqualand District, Springbok , Goegap Nature Reserve, SE of workers’ houses, 850 m, (2918CA), 17 September 2010, Steyn 1825 [collected by Geldenhuys] (KMG!, NBG!, PRE!) ; Farm Silwerfontein, turn-off about 12 km from Springbok on the road to Gamoep , about 15 km after the turn-off to the farmhouse, 728 m, (2918CC), 29 August 2012, Koekemoer 4360 ( PRE!) ; Little Namaqualand, common on dry mountain slopes south of Tweefontein , 3000 ft, [915 m] (2918CD), 25 December 1908, Pearson 3783 ( BOL!) ; Namaqua National Park, track to the SW of dam N of Jantjieskop, Roodelaagte Farm , 172 m, (3017AB), 17 August 2009, Steyn 1625 ( PRE!) ; Namaqua National Park, between Jantjieskop and Riethuis , Farm Roodelaagte , 170 m, (3017AB), 18 August 2009, Steyn 1629 ( PRE!) ; Namaqua National Park, between Taaibosduin and Hondeklipbaai road, dune fynbos near soil dam, 160 m, (3017AD), 12 August 2006, Sachse 222 ( PRE!) ; Namaqualand , 14 mi. [22.5 km] W of Kamieskroon, 1500 ft [457 m], (3017BA), 23 September 1952, Acocks 16445 ( PRE!) ; Namaqua National Park, secondary track leading to right from 4x4 track between Kykokeis and Kookfontein , 344 m, (3017BA), 14August 2009, Steyn 1585 ( PRE!) ; Namaqua National Park, 4x4 track between Kykokeis and Kookfontein , 294 m, (3017BA), 14 August 2009, Steyn 1589 ( PRE!) ; Namaqua National Park, between Soebatsfontein and Skilpad , 318 m, (3017BA), 16 August 2009, Steyn 1619 ( PRE!) ; Little Namaqualand, Kamieskroon, near Kamieskroon , (3017BB), 24 July 1941, Esterhuysen 5464 ( BOL!, PRE!) ; Namaqualand, Kamieskroon, Skilpad Wildflower Reserve , (3017BB), 6 August 1993, Grobler 22 ( PRU!) ; Namaqua National Park, on cement road section between Skilpad and Soebatsfontein at foot of koppie, 553 m, (3017BB), 29 December 2010, Koekemoer 3999 ( PRE!) ; Namaqualand District, Boesmanplaat, along a turn-off to the west of the road between Gamoep and Platbakkies , 936 m, (3017BB), 16 August 2013, Koekemoer 4401 ( PRE!) ; Namaqualand District, Kamiesberg, at the first large granite rocks along the road between Kamieskroon to Pedroskloof , 847 m, (3017BB), 16 August 2013, Koekemoer 4397 ( PRE!) ; Namaqualand District, No Heep road N of Kamieskroon, 744 m, (3017BB), 2 September 2010, Steyn 1768 ( PRE!) ; Namaqualand District, between No Heep road & Bloupoort turn-off, 672 m, (3017BB), 2 September 2010, Steyn 1769 ( PRE!) ; Namaqualand District, Namaqua National Park, 1 km S of look-out point on track to Soebatsfontein , 558 m, (3017BB), 11 August 2011, Steyn 1859 ( PRE!) ; Namaqualand District, Namaqua National Park, 1 km S of look-out point on track to Soebatsfontein , 558 m, (3017BB), 11 August 2011, Steyn 1859b ( PRE!) ; Namaqualand District, Namaqua National Park, on road between Skilpad and Soebatsfontein , 558 m, (3017BB), 26 August 2012, Steyn 1892 ( PRE!) ; Namaqualand, Kamieskroon, Skilpad Wildflower Reserve of southern African Nature Foundation , Relevé : 22, (3017BB), 13 July 1993, Van Rooyen 2472 ( PRE!, PRU!) ; Kamieskroon, Bloupoort , 900 m, (3017BB), 4 September 2001, Venter JV 9612(JV-46) ( KMG!, PRE!) ; southeast of Hôsabees in ‘ Pypmaker se Poort’ , road to Goraap , 950 m, (3018AB), 26 August 1987, Hilton- Taylor 2241 ( NBG!) ; Upper Namaqualand & Karoo, gneiss ridges west of outspan, Alewyn’s Fontein , (3018BC), 23 December 1908, Pearson 3490 ( BOL!) .

Without precise locality: Mund s.n. (K!); Drège s.n. (2437) (K!, P!, S!, TCD scan!).

Figures

FIGURE 1. Known distribution of the shrublet species of Acanthopsis: A. spathularis (○), A. horrida (●), A. erosa (■) and A. dregeana (▲).

FIGURE 3. Comparison of floral parts in shrublet species of Acanthopsis (from left to right): bract(s), bracteoles, calyx (4 sepals: dorsal, ventral and 2 lateral ones) and flower. A. A. spathularis, B. A. horrida, C. A. erosa, D. A. dregeana. Note: the bract on the left is from lower down in the same inflorescence. Scale bar = 10 mm. Vouchers:A = Steyn 2135 (PRE), B = Koekemoer 4397 (PRE), C = Steyn 1874 (PRE), D = Steyn 1822 (PRE).

FIGURE 4. Scanned image of holotype of Acanthopsis spathularis (Nees) Schinz (Drège 2440, P (MNHN collection-Paris)).

FIGURE 7. Habit and flowers of A, A. spathularis, B. A. horrida, C. A. erosa, D. A. dregeana. Photographs: H.M. Steyn (A, a, B), M. Koekemoer (b, C, d), S.P. Bester (c, D).