Hyobanche thinophila A. Wolfe, 2013

Wolfe, Andrea D., 2013, Hyobanche thinophila (Orobanchaceae), a new species from the Western Cape of South Africa, Phytotaxa 85 (2), pp. 56-60 : 57-58

Hyobanche thinophila A. Wolfe sp. nov. Fig. 1 A–H

TYPE:— SOUTH AFRICA. Western Cape: Koeberg Nature Reserve , 33°08'56.8" S, 18°24' 55.9" E, 26 m, 10 September 2004, Wolfe 1174 (Holotype: NBG!).

Perennial holoparasitic herb; achlorophyllous, lacking leaves and roots; rhizomatous with one to several yellowish rhizomes extending deep into sand dune, numerous secondary haustoria forming from scales where host roots contact rhizome; scales ovate to oblong, 5.0–13.0 × 4.0–10.0 mm, apex acute to slightly obtuse, upper margin ciliate with short multicellular trichomes, abaxial surfaces of above-ground scales puberulent near apex, scales mostly glabrous below ground. Inflorescence a densely-flowered spike, ovate to slightly oblong, 8.3–15.4 × 3.8–6.7 cm; flowers tubular with two lateral bracteoles, subtended by a single bract on the abaxial side; floral bract 1.9–3.4 × 0.7–1.4 cm, oblong and keeled adaxially, acute to slightly obtuse, upper margins slightly scarious and entire, proximally pubescent, becoming pubescent to pilose on the distal abaxial surface and densely pubescent on the distal adaxial surface; bracteoles 2.7–3.9 × 0.2–0.5 cm, lanceolate to broadly linear, acute to acuminate, the upper half pilose. Flowers sessile to subsessile; calyx 3.8–5.1 cm, four of five sepals fused to ¼–½ their length, the abaxial sepal free or connected to other sepals near calyx base, sepal lobes lanceolate to broadly linear, acute, pilose; corolla light pink, 5.6–6.2 × 1.0– 1.4 cm, tubular or slightly curved, slightly inflated above constricted tube 1.1–1.8 × 0.5–0.9 cm, densely pilose with two minute lapel-like lateral lobes and a small denticle at the base of the corolla mouth, lateral lobes slightly to fully reflexed, denticle 1.7–3.3 mm, corolla mouth 1.4–2.0 cm; stamens 4, inserted in the corolla at the point of constriction, 3.4–4.2 cm, one pair slightly shorter than the other, filaments straight with slightly inflated bases, pubescent to tomentose zone at base of stamens and ringing interior surface of corolla at level of insertion, anthers 3.0–5.0 × 2.0–3.0 mm, calceiform, one-celled, small knob or spur on proximal end from vestigial theca, apical pore elongated and slightly recurved, even with corolla mouth to slightly exserted at maturity; pistil recurved ca 90° below stigma, stigma exserted, clavate to nearly capitate, slightly bilobed dorsiventrally. Fruits not seen.

Phenology. Hyobanche thinophila flowers in the late winter to early spring (August–September), depending on the timing of the winter rains in the Western Cape. One to several inflorescences arise from a single rhizome that may be more than a meter in length.

Distribution. Sand dunes along the coast of South Africa from Struisbaai in the south to Yzerfontein in the west ( Fig. 2 ).

Ecology. Hyobanche thinophila occurs in early successional sand fynbos habitat ( Mucina & Rutherford 2006). The host range for Hyobanche is difficult to determine based on the proximity of other plants because the rhizome system of the parasite can be quite extensive. However, host roots attached to the rhizome of the parasite were collected and their DNA extracted for a barcoding study aimed at identifying the hosts of Hyobanche thinophila (unpublished data). Three genera have thus far been identified as hosts to H. thinophila : Metalasia R. Brown and Chrysanthemoides Tournefort ex. Medikus ( Asteraceae ), and Passerina L. ( Thymelaeaceae ).

Etymology. The specific epithet is after the Greek words for sand-dune-loving.

Common names [Afrikaans (English)]. Duin katnaels (dune cat nails), duin wolwekos (dune wolves food), duin inkblom (dune ink bloom). The white, exserted and recurved styles of Hyobanche are the primary reason for katnaels as a common name. Wolwekos as a common name is a misnomer. Wolves are not native to South Africa; the niche of wolves is filled by the African wild dog. The origin of this common name is unknown, but may refer to the resemblance of the inflorescence to fresh scraps of carrion ( Manning 2007). Inkblom refers to the use of the plant for making ink ( Smith 1966). Hyobanche , similar to other genera in Orobanchaceae , tends to dry black after harvesting the inflorescence. Dried material is then ground into powder and added to liquid to make ink.

Taxonomic notes. Hyobanche thinophila is easily differentiated from H. sanguinea by dissecting the corolla to examine the interior vestiture: a ring of long multicellular hairs at the level of stamen insertion in H. thinophila vs. short glandular hairs scattered throughout the interior surface of the corolla in H. sanguinea . The shape of the inflorescence is ovate to slightly elongated in H. thinophila vs. compact to oblong in H. sanguinea . Flowers of H. thinophila are light pink, tubular and non-galeate, and slightly curved to straight vs. scarlet to deep red, galeate and strongly curved in H. sanguinea .

Additional specimens examined: SOUTH AFRICA. Western Cape: Koeberg Nature Reserve , 33°08'56.8" S, 18°24' 55.9" E, 26 m, 06 September 2002, Wolfe 1026 ( OS) ; Cape Peninsula: Fish Hoek , 1916, Glover s.n. ( BOL) ; Cape Peninsula: Noordhoek Beach , 34°S 18°E, 3 m, 20 September 2010, Wolfe 1364 ( OS) ; Pringle Bay , 34.38190 S, 18.82493 E, 12 m, 22 September 2001, Wolfe 939 ( OS) ; Pringle Bay , 34°20'46.5" S, 18°49'40.2" E, 16 m, 16 September 2002, Wolfe 1060 ( OS) ; Hangklip , 34°22'54.9" S, 18°49'30.2"E, 10 m, 4 September 2002, Wolfe 1021 ( OS) ; Betty's Bay , 20 m, 6 September 1942, Leighton s.n. ( BOL) ; Betty's Bay , 34°S, 18°E, 20 m, 14 August 1982, Burman 830 ( BOL) ; Struisbaai , 34°45.631 S, 20°02.650 E; 2 m, 24 September 2004, Wolfe 1202 ( OS) ; Struisbaai , August 1940, Esterhuysen 5042 ( BOL) .

Figures

FIGURE 1. A–H Hyobanche thinophila. Scale bar for A-B below B; scale bar for C-H below D. A. Habit. B. Rhizome. C. Complete flower with bract and bracteoles. D. Corolla interior. E. Pistil. F. Flower bract. G. Flower bracteoles. H. Calyx, showing four fused sepals and one free.

FIGURE 2. Distribution map of Hyobanche thinophila, which is endemic to the coastline of the Western Cape from Cape Agulhas to the Atlantic coast.