Schizobasis litanthiflora N.R.Crouch & Mart.

Crouch, Neil R. & Martínez-Azorín, Mario, 2024, Schizobasis litanthiflora (Hyacinthaceae, Urgineoideae), a new species from the Tugela River Basin of KwaZulu-Natal, South Africa, Phytotaxa 672 (2), pp. 199-207 : 203-205

Schizobasis litanthiflora N.R.Crouch & Mart. -Azorín, sp. nov. ( Fig. 1A–F , Fig. 2 )

Diagnosis:—It resembles Schizobasis intricata but differs by the long lasting, nodding tubular constricted flowers with included stamens and very long style.

Type:— SOUTH AFRICA. KwaZulu-Natal: Stanger (2931): eMabhobhane (- AA), elevation 700 m, Eastern Valley Bushveld, flowered in cultivation in Alicante , 28 March 2024, N. Crouch 1302 (holotype GRA; isotype ABH) .

Deciduous herb. Bulb solitary, hypogeal to rarely semi-hypogeal, subglobose to ovate-oblong, short-necked, 25–60 mm length; outer bulb scales fleshy, with residual papery tunic fragments, green to pale beige, with contractile roots. Leaves shortly deciduous, one or two, filiform, up to 30 × 0.5 mm. Inflorescence solitary, 50–170 × 40–130 cm, scape 5–90 mm long, ca 0.3 mm in diameter, erect, arching, scabridulous at base, flushed purple below, moderately to extensively branched, branches alternate, divaricate, straight or curving, first degree branches 12–24 mm long, shortening to 3 mm long distally; lowermost bracts lanceolate, 0.6–1.0 mm long with spur 0.2–3.0 mm long, present at all nodes and shortening distally, sometimes deciduous; pedicels subpatent, becoming downward curved distally, but apically erect in fruit, 13–14 mm long in flower. Flowers tubular, nodding, subglobose at base, slightly constricted around middle, with slightly spreading apices, 5.0–7.0 × 1.8–3.0 mm, white with purplish-brown midvein and greenish around base, without discernable odour; tepals 4.5–6.5 × 1.5–1.7 mm, shortly connate in basal 1 mm, inner tepals narrowly obovate and narrowed at middle; outer tepals lanceolate, overlapping inners. Stamens included, adnate to perianth for ca 1 mm, thus inserted at top of tube; filaments filiform, erect, free for ca 2.5 mm long; anthers connivent around style, dorsifixed, introrse, thecae ca 1 × 0.6 mm long before dehiscence, longitudinally dehiscent, connective very shortly apiculate. Ovary ovate-subglobose, ca 1.7 × 1.4 mm, greenish yellow with white septal nectaria; style columnar, tapering along upper third, 2.8–3.5 mm long, longer than ovary, extending well beyond anthers by ca 1.2 mm, greenish along basal third and white distally, stigma obtuse, minutely 3-lobed. Capsule subglobose, ca 3.5 × 3.5 mm, presented sigmoidally to dehisce vertically, brown. Seeds ca 4–5 per locule, hemicircular, irregularly compressed with slightly winged margins, (2.6–)2.8–3.0 × (1.4–)1.6–1.7(–2.0) mm, testa glossy black, rugose and comprised of narrowly elongated cells aligned to long axis, cell edges slightly wavy.

Etymology:—Named after the urgineoid genus Litanthus , given its superficially similar tubular flower morphology and dimensions, and nodding presentation.

Phenology: — Schizobasis litanthiflora flowers mainly from July to October in the wild, with occasional flowers to early January concurrently with mature fruits; in cultivation in the Northern Hemisphere (Alicante, Spain) between March and May. The flowers last about three days, considerably longer than other Schizobasis species in which flowers are fugacious and last a single day. Mature fruits are produced from October to January in the wild and observed from April in the Northern Hemisphere.

Habitat: — Schizobasis litanthiflora occurs in well-drained shallow loamy soils overlying Natal Group Sandstones at the base of shrubs on rocky krantzes, and in rock crevices, on western and northwestern aspects ( Fig. 1G ). The savanna vegetation type within which it has been found is Eastern Valley Bushveld (SVs 6) ( Rutherford et al. 2006), at an elevation of 700 m.

Distribution:— Schizobasis litanthiflora is presently only known from the type locality at eMabhobhane in the Stanger District, within the valley of the Tugela River, in central KwaZulu-Natal ( Fig. 3 ). Several hundred plants have been observed at the site.

Diagnostic characters and taxonomic relationships:— Schizobasis litanthiflora is unique in the genus in producing nodding tubular flowers, which although seemingly having fused tepals for most of their length, are comprised rather of almost free, erect and overlapping tepals; included stamens; and subglobose ovary with elongated style ( Fig. 2A–B ). All other species in the genus produce spreading tepals that expose the androecium and gynoecium at anthesis (see figs. 44–46 in Martínez-Azorín et al. 2023a).

Discussion:—In their treatment of the “ Schizobasis group of Drimia ”, the inclusion by Manning et al. (2014) of eight morphologically highly diverse species in their concept for D. intricata inevitably resulted in a very broadly circumscribed taxon concept, for an entity widespread in southern and central Africa. In the sense of Manning and co-workers (2014) D. intricata flowers from early through to late summer (November to March in the Southern Hemisphere). The plant figured as Drimia intricata by Manning et al. (2014, figure 1) and Manning & Goldblatt (2018, figure 32) and based on D. van der Walt sub J. Deacon 3133 (NBG), was gathered originally in the Port Elizabeth District of the Eastern Cape province, and represents a far narrower species concept than that detailed in the description provided by these authors.

In consideration of specimens from KwaZulu-Natal used to inform their opinion of their concept for D. intricata , none were cited by Manning et al. (2014) for that province, despite their figure 2 showing a distribution at the topacadastral QDS 2831BD within the Nkandla District. This distribution point would appear to roughly correspond with Venter 3000 (PRE!) cited earlier by Jessop (1977) from near the Old Gold Mine, Babanango. Jessop (1977) also cited a photographic voucher of a plant from Rooikrans above the Bivane (Pivaan) River in Louwsburg District (Dyer 5042, PRE!), from 2731CA. Neither of these vouchers nor Schizobasis plants encountered by us at these localities corresponds with the material from eMabhobhane on the Tugela, either vegetatively or sexually. Without explanation, the subsequent revision of Drimia s.l. in southern Africa by Manning & Goldblatt (2018) did not reflect any localities within KwaZulu-Natal on their distribution map (67) for D. intricata , nor were the PRE vouchers seen by Jessop and ourselves cited by them.

Schizobasis litanthiflora is unusual in the genus for flowering in situ mainly during late winter through to late spring, much earlier in the season than its summer-flowering sister taxa. Although similar in overall floral form and dimensions the tepals of both Litanthus species are connate for three quarters to four fifths of their length into a cylindrical tube ( Fig. 2C–E ), whereas those of S. litanthiflora are connate only in their basal fifth and so otherwise free, but are similarly borne as pendulous cylindrical tubes ( Fig. 1A, D ; Fig. 2A ). The strong similarity in overall form of the corolla of S. litanthiflora to that of Litanthus is intriguing, leading one to speculate on the evolutionary pressures that may have brought about such convergence. The notion that the widespread Litanthus pusillus Harvey (1844: 315) and S. litanthiflora might mutually support a pollination guild at the eMabhobhane locality is not yet substantiated by observations for co-occurrence of L. pusillus plants (although this latter species also occurs along the Tugela River). The asynchronous but largely successive phenologies of these two species would enable pollinator rewards to extend across a longer season, given that S. litanthiflora plants flower mainly from July to October, and L. pusillus blooms thereafter between November and March.

Figures

FIGURE 1. Schizobasis litanthiflora N.R.Crouch & Mart.-Azorín from the type locality at eMabhobhane. A. Inflorescence section, with mature flowers and buds; B. Infructescence; C. Entire plant with immature fruits; D. Pendulous flower in lateral view; E. Mature capsule with seeds; F. Seed in lateral view. G. Habitat at type locality. Scale bars: A: 4.5 mm, B: 25 mm, C: 20 mm, D, E: 2 mm, F: 0.7 mm. Photographs by the authors.

FIGURE 2. Schizobasis and Litanthus flower morphology: Schizobasis litanthiflora N.R.Crouch & Mart.-Azorín from the type locality in cultivation (A–B). A. Mature flowers and dissections; B. Dissected immature flowers; C. Litanthus pusillus Harvey from Harvey (1844: Tab. IX); D. Litanthus pusillus; E. Litanthus stenocarpus (J.C.Manning & J.M.J.Deacon) Mart.-Azorín et al. Scale bar: 5 mm. Photographs by the authors.

FIGURE 3. Known geographic distribution range of Schizobasis litanthiflora N.R.Crouch & Mart.-Azorín (■).