Lachenalia barbarae G.D.Duncan, 2017

Duncan, Graham D., 2017, Two new species, two rediscoveries and a range extension in Lachenalia (Asparagaceae: Scilloideae) from southern and western South Africa, Phytotaxa 316 (3), pp. 261-270 : 262-265

Lachenalia barbarae G.D.Duncan , sp. nov. ( Figs. 1–3 ).

Type:— SOUTH AFRICA. Western Cape: Haarwegskloof Renosterveld Reserve between Bredasdorp and Swellendam (3420 AC), scattered solitary plants and small clumps in quartz patch overlaying shale on northwest-facing hillside, between low scrub and moss-covered stones, in full sun, elevation 245 m, 34.335°S, 20.322°W, 14 Dec. 2015, Duncan 669 (holotype: NBG).

This new species differs from L. magentea Duncan (2012: 343) in having suberect, light pink flowers with shorter, elliptical outer tepals 3–5 mm long, included or exserted stamens with spreading, much shorter filaments 3–5 mm long, longer, deep maroon peduncles, 60–165 mm long, shorter pedicels 3–5 mm long, larger, ovoid seeds 1.5–1.6 × 1.1–1.2 mm, longer, adult leaves 180–300 mm long, dying back shortly before flowering begins, prostrate or spreading primary seedling leaves with flat surfaces, ovoid, solitary bulbs and a much later flowering time in December and January.

Deciduous, winter-green geophyte 85–260 mm high. Bulb ovoid, 15–22 mm in diam., solitary; tunic multilayered, outer layers dark brown, inner layer[s] translucent white; cataphyll 15 mm long, translucent white below, apex acute, green. Leaves (1) 2(3), linear, 180–300 × 3–6 mm, suberect or recurved, light green, dying back shortly before flowering, upper surface unmarked, lower surface spotted or barred with dull maroon towards base; clasping leaf base mostly subterranean, white, 10–15 mm long; primary seedling leaf linear, prostrate or spreading, brownish maroon. Inflorescence a raceme, 3–10-flowered; peduncle erect or suberect, 60–165 mm long, rigid, deep maroon, glaucous; rachis 25–95 mm long, light maroon in lower half, shading to light pink above; bracts cup-shaped at base of inflorescence, becoming lanceolate above, 1–2 × 1–3 mm, white; pedicels 3–5 mm long, shortest at top of rachis, white or light pink. Perianth zygomorphic, narrowly campanulate, suberect, tube shallowly cup-shaped, 2 mm long, light pink, outer tepals elliptical, 3–5 × 2–3 mm, light pink, apical gibbosity oblong, deep pink, inner tepals obovate, 4.0–5.0 × 3.0– 3.5 mm, protruding up to 1 mm beyond outer tepals, light pink, median keel deep pink. Stamens included or exserted, filaments white, 3–5 mm long, anthers oblong, 1 mm long, pollen yellow. Ovary ovoid, light green, 1.1– 2.0 × 1.2–2.0 mm; style straight, white, 3–4 mm long; stigma capitate. Capsule obovoid, 5–6 × 4–6 mm, suberect. Seeds ovoid, 1.5–1.6 × 1.1–1.2 mm, glossy, black; strophiole 0.3–0.4 mm long, ridged. Flowering time: December to January.

Etymology:— The specific epithet barbarae honours Mrs Barbara Taylor, mother of Mr Oren Taylor who has made significant financial contributions towards supporting efforts to save renosterveld vegetation from extinction in the Western Cape.

Other material examined:— SOUTH AFRICA. Western Cape: Haarwegskloof Renosterveld Reserve (3420 AC), quartz patch overlaying shale, 34.338°S, 20.326°W, 5th January 2011, Curtis s.n. (Haarwegskloof Private Herbarium) ; December 2014, Groenewald s.n. ( NBG) .

Notes:— The first collection of plants was made at Haarwegskloof Renosterveld Reserve on 5 January 2011 by Odette Curtis , Director of the Overberg Renosterveld Conservation Trust. The two specimens collected were in late flowering stage, and she was unaware that they represented a new species. During subsequent flowering seasons, Jannie Groenewald, Manager of the Reserve, considered it to be an undescribed species, since he was unable to identify it from the literature. Following the 2014 flowering season, seeds and a single bulb collected by Groenewald were brought to the bulb collection at Kirstenbosch National Botanical Garden by Rhoda McMaster, a member of the local Custodians of Rare and Endangered Wildflowers ( CREW). The bulb flowered in cultivation at Kirstenbosch in early December 2015 and was confirmed to be an undescribed species ; a line drawing was prepared by Vicki Thomas. Shortly thereafter, the author visited the site at Haarwegskloof to study the plants in habitat and collect type material.

Diagnostic features and affinities:— Lachenalia barbarae is recognised in flower by an erect or suberect, deep maroon, rigid peduncle bearing a raceme of small, light pink, narrowly campanulate, suberect flowers carried on white or light pink pedicels ( Figs. 1 , 2 ). It has shallowly cup-shaped perianth tubes and weakly spreading tepals. The inner tepals protrude slightly and have deeper pink median keels, and the outer tepals have prominent deeper pink apical gibbosities. The flowers have short, included or exserted, weakly spreading white stamens, and bracts that are cup-shaped at the base of the inflorescence and lanceolate above. It is further recognised by usually two, or rarely one or three linear, suberect or recurved green leaves with acute apices, unmarked upper surfaces, and lower surfaces that are lightly spotted or barred with dull maroon towards the base. The inflorescence emerges directly after the leaves have withered, and the primary seedling leaf is linear with prostrate or spreading orientation. The fruit is an obovoid capsule containing ovoid, glossy, black seeds with short, ridged strophioles.

Lachenalia barbarae is included in subgenus Lachenalia because of its zygomorphic perianth and in section Angustae due its narrowly campanulate perianth shape ( Duncan 2012). It appears closely allied to L. magentea from the southern Cape coastal belt. Lachenalia magentea has a similar narrowly campanulate perianth with a shallowly cup-shaped tube, subequal tepals, suberect pedicels and obovoid capsules, but differs in having a larger, cernuous or spreading perianth with longer, white tepals with magenta apical gibbosities and magenta median keels, and longer, shortly to well-exserted, straight filaments. It differs further in having heavily maroon-dotted, light green peduncles and subterete, synanthous adult leaves, terete, erect primary seedling leaves, offset-forming bulbs and globose seeds 1.1–1.2 × 1.3 mm. Lachenalia magentea flowers earlier (August to October) and occurs close to the coast in sandy soils in Agulhas Sand Fynbos and Agulhas and Canca Limestone Fynbos vegetation ( Duncan 2012).

Distribution and habitat:— Lachenalia barbarae occurs within the Fynbos Biome and is endemic to the Overberg region of the Western Cape, in the east coast Renosterveld Bioregion ( Mucina & Rutherford 2006). It is highly localised to a northwest-facing hillside within the Haarwegskloof Renosterveld Reserve between Bredasdorp and Swellendam, at an elevation of 245 m ( Fig. 3 ). The plants occur as scattered individuals or in small groups of up to six plants on quartz patches overlaying shale, in Eastern Rûens Shale Renosterveld, a vegetation type that is critically endangered due to over 80% having been transformed to cultivation ( Mucina & Rutherford 2006). The shallowly seated bulbs occur on moss-covered ground between quartz pebbles, stones and rocks in association with the quartz-endemic succulent Drosanthemum asperulum (Salm-Dyck, 1842: 50) Schwantes (1927: 30) ( Aizoaceae ), the grass Pentameris eriostoma ( Nees, 1841: 304) Steudel (1841: 298) ( Poaceae ), and the renosterveld shrub Elytropappus rhinocerotis ( Linnaeus, 1781: 391) Lessing (1832: 344) ( Asteraceae ). When in flower, L. barbarae is variable in height, ranging from short specimens 85 mm high in exposed situations to relatively tall plants up to 260 mm high, emerging through vegetation. The species flowers late in the season (early December to early January) in mid-summer and is visited by the small, common hairtail butterfly Athene definita ( Lycaenidae ) and a small, unidentified solitary wasp.

Figures

FIGURE 1. Lachenalia barbarae, drawn from Groenewald s.n. A. Flowering plant. B. Single flower in lateral view. C. Single flower in front view. Scale bars: 10 mm. Illustration byVicki Thomas.

FIGURE 2. Lachenalia barbarae, general view of quartz habitat in Eastern Rûens Shale Renosterveld, Haarwegskloof Renosterveld Reserve, southern Cape (A.) and flowering plants (B, C). Photographs by Graham Duncan.

FIGURE 3. Distribution of Lachenalia barbarae (black dot) in southern South Africa and Lachenalia adamii (black star) in western South Africa.