Zulusia Mart.-Azorín, N.R. Crouch, M.B.Crespo & M.Á.Alonso, 2023

Martínez-Azorín, Mario, Crespo, Manuel B., Alonso-Vargas, María Ángeles, Pinter, Michael, Crouch, Neil R., Dold, Anthony P., Mucina, Ladislav, Pfosser, Martin & Wetschnig, Wolfgang, 2023, A generic monograph of the Hyacinthaceae subfamily Urgineoideae, Phytotaxa 610 (1), pp. 1-143 : 125-128

31. Zulusia Mart.-Azorín, N.R. Crouch, M.B.Crespo & M.Á.Alonso gen. nov.

( Figs 76–77 ).

Typus generis:— Z. delagoensis (Baker) Mart.-Azorín, N.R. Crouch, M.B.Crespo & M.Á.Alonso ≡ Urginea delagoensis Baker (holotype).

Diagnosis:— Genus notabilis a Sekanama accedens , sed singulari characterum combinatione ab ea diversus et facile distinguendus, nempe foliis synanthis; racemo quam inflorescentiae pedunculo longiore; floribus subbrunneis, carneis vel virescentibus; tepalis emarcidis ad apicem capsulae persistentibus; capsulis anguste ellipsoideis vel fusiformibus; et seminibus anguste oblongo-fusiformibus.

Description:—Bulbous geophyte. Bulb epigeal or hypogeal, ovoid to subglobose, sometimes proliferous and clump forming, with loosely packed, thick, fleshy scales, sometimes very loose, cucullate and pedicellate. Leaves 1‒8 per bulb, narrowly lanceolate to filiform, canaliculate, green, glabrous to denticulate, 7‒45 cm long. Inflorescence long racemose, 10‒65 cm long, with 10‒60 flowers; peduncle 15‒60 cm long, terete, erect, green to greyish, sometimes papillose-hairy at base; pedicels 2.5‒6.0 mm long. Bracts lanceolate, 2‒5 mm long, lowermost with spur 3.5‒4.0 mm long. Bracteoles absent. Flowers subcampanulate, erect-patent, diurnal. Tepals 6, biseriate, 3‒6 mm long, lanceolate to oblong, light brown, creamy white or pale mauve, with darker longitudinal band, almost free to very shortly connate, connivent along basal half to form campanulate structure and spreading-patent in upper portion of tepals. Stamens 6, erect or slightly spreading; filaments filiform, 2.5‒4.0 mm long, suberect, adnate to tepals along their basal portion; anthers dorsifixed. Ovary ovate to ellipsoid, green. Style 1.5‒2.5 mm long, erect, white, with trigonous stigma. Capsules narrowly ellipsoid to fusiform, 7‒10 mm long, valves completely dehiscing from base; tepals cohering and inrolled above ovary after anthesis, circumcissile from base and persisting as a cap at the top of the developing capsules. Seeds narrowly oblong-fusiform, elongated, ca. 3‒5 times longer than wide, 4‒8 mm long, embryo prominent with very narrow, indistinct wings, black, glossy, testa longitudinally striate, with elongate, slightly sinuous anticlinal cell walls.

Number of species and distribution:— Zulusia is restricted to eSwatini (formerly Swaziland) and the KwaZulu-Natal and Mpumalanga Provinces in South Africa.The genus includes three species restricted to the Uzambara-Zululand Region (sensu Takhtajan 1986) ( Fig. 71 ). For further information on Zulusia species see Dyer (1942 a, 1942b), Jessop (1977), Crouch & Martínez-Azorín (2015), and Manning & Goldblatt (2018).

Karyology:—2n=32 ( De Wet 1957, as Urginea lydenburgensis R.A.Dyer ), indicating clear chromosomal differences between Sekanama s.str. and Zulusia . Caryological studies of other members of the genus would prove insightful.

History, diagnostic characters, and taxonomic relationships:— Speta (2001) described Sekanama to include Urginea sanguinea , U. burkei , and U. delagoensis , the latter species is sometimes including U. lydenburgensis in synonymy ( Jessop 1977, Manning & Goldblatt 2018), although field observations, ethnomedicinal trade research in Nelspruit (Mpumalanga), and phytochemical profiling support their distinction ( Koorbanally et al. 2005, Mullholland et al. 2013, Crouch & Martínez-Azorín 2015). Drimia edwardsii was described from KwaZulu-Natal ( Crouch & Martínez-Azorín 2015), sharing flower and fruit morphologies with S. delagoensis and U. lydenburgensis . Our studies have shown important differences in morphology between S. sanguinea (including U. burkei ) and the remaining taxa in this group. Sekanama sanguinea is distributed in the inland areas of northern South Africa, Botswana, and Namibia and shows hysteranthous leaves; racemose inflorescences with peduncle much shorter than the raceme; white flowers; withered tepals persisting at base of capsule; ovoid-ellipsoid capsule; and flat and wide, elliptic seeds. Urginea delagoensis , U. lydenburgensis , and Drimia edwardsii are collectively distributed in eSwatini and the neighbouring South African province of KwaZulu-Natal and produce synanthous leaves; peduncle longer than the raceme; pale brown or carneous to greenish flowers; withered tepals persisting at the top of the capsule; narrowly ellipsoid capsules; and narrowly lanceolate seeds.

Our phylogenetic study of Sekanama ( Martínez-Azorín et al. 2023a) revealed the analysed three samples of S. sanguinea to form a strongly supported clade. Samples of U. delagoensis , D. lydenburgensis , and D. edwardsii formed another strongly supported clade, with both groups shown related but with very weak support. Based on their phylogenetic divergence and the differences in morphology and biogeography of the two clades, we restrict Sekanama to include S. sanguinea (with S. burkei in synonymy) and related taxa sharing red and fleshy bulb scales, small and navicular bracts, presence of bracteoles, and the papery-translucent withered tepals mostly remaining at the base of developing capsules, and describe here the new genus Zulusia to accommodate U. delagoensis , U. lydenburgensis , and D. edwardsii .

In their D. sect. Macrocentrae Manning &Goldblatt (2018) placed both Urginea macrocentra (= Boosia sensu Speta 2001 ) and U. sanguinea ( Sekanama p.p. sensu Speta 2001), apparently overlooking the previous phylogenetic work of Pfosser & Speta (2001, 2004), in which both these taxa resolved in different and distant clades in the phylogeny—an earlier finding in agreement with more recent phylogenetic results ( Martínez-Azorín et al. 2023a). Further, Manning & Goldblatt (2018) placed U. delagoensis (including U. lydenburgensis ) and D. edwardsii in their D. sect. Ledebouriopsis among eleven heterogeneous species including Urgineopsis and Ornithogalum anomalum (the monotypic Geschollia sensu Speta 2001 ), thus resulting in a polyphyletic aggregate according to the then available phylogenetic works ( Pfosser & Speta 2001, 2004), later confirmed by Martínez-Azorín et al. (2023a). Section Ledebouriopsis sensu Manning & Goldblatt (2018) merges species located in five genera ( Zulusia , Urginavia , Urgineopsis , Geschollia , and Boosia ) following the present study, and therefore this group is disregarded here. The name Zulusia has been selected in recognition of the importance of both U. delagoensis and D. edwardsii in the ethnomedicinal traditions of the Zulu nation. As recounted by Crouch & Martínez-Azorín (2015), D. edwardsii was first observed in the ethnomedicinal plant trade, some 15 years prior to its location by taxonomists in the field, and subsequent description.

Accepted species and required new combinations:—

Zulusia delagoensis (Baker) Mart.- Azorín, N.R. Crouch, M.B.Crespo & M.Á.Alonso comb. nov. ≡ Urginea delagoensis Baker, Fl. Cap. (Harvey) 6(3): 467 (1897), basionym ( Figs 6.7 , 76.1 , 77.1 ). Type:— MOZAMBIQUE. Between Delagoa Bay [Maputo] and the Lebombo Mountains , 1886, H. Bolus 7627 (K000257346! holo.; BOL s.n.! iso.).

Zulusia edwardsii (N.R.Crouch & Mart.-Azorín) Mart. - Azorín, N.R. Crouch, M.B.Crespo & M.Á.Alonso comb. nov. ≡ Drimia edwardsii N.R.Crouch & Mart. - Azorín in Phytotaxa 195(2): 137 (2015), basionym ( Figs 6.8 , 76.3 , 77.2 ). Type:— SOUTH AFRICA. KwaZulu-Natal. Port Shepstone (3030): middle Mkhomazi River , on north-facing shale rock ledge, 400 m, (–AA), 21 September 2011, N. Crouch 1280 (BNRH! holo.; HSMC! iso.).

Zulusia lydenburgensis (R.A.Dyer) Mart.- Azorín, N.R. Crouch, M.B.Crespo & M.Á.Alonso comb. nov. ≡ Urginea lydenburgensis R.A.Dyer in Fl. Pl. South Africa 22: t. 859 (1942), basionym ( Figs 6.9 , 76.2 , 77.3 ). Type:— SOUTH AFRICA. Mpumalanga, Lydenburg District , September 1937, Swart 12268 sub PRE23303 (PRE0048567-1, PRE0048567-2 holo.!).

Figures

FIGURE 6. Seed morphology in Urgineoideae. 1. Urgineopsis salteri Compton; 2. Vera-duthiea capillifolia A.Patzelt et al.; 3. Veraduthiea sp. (Urginea petrophila A.Chev., nom. nud.); 4. Vera-duthiea sebiri (Berhaut) Mart.-Azorín et al.; 5. Vera-duthiea sp. (Urginea segetalis A.Chev., nom. nud.); 6. Zingela pooleyorum N.R.Crouch et al.; 7. Zulusia delagoensis (Baker) Mart.-Azorín et al.; 8. Zulusia edwardsii (N.R.Crouch & Mart.-Azorín) Mart.-Azorín et al.; 9. Zulusia lydenburgensis (R.A.Dyer) Mart.-Azorín et al.; 10. Urginea cf. aurantica H.Lindb.; 11. Urginea revoluta A.V.Duthie.All to the same scale in mm.

FIGURE 71. Approximate distribution ranges of accepted genera in Urgineoideae.

FIGURE 76. Species of ZulusiaMart.-Azorín et al.1.Zulusia delagoensis (Baker)Mart.-Azorín et al.from Dyer(1942a:pl.858, asUrginea delagoensis Baker); 2. Zulusia lydenburgensis (R.A.Dyer) Mart.-Azorín et al. from Dyer (1942b: pl. 859, as Urginea lydenburgensis R.A.Dyer); 3. Zulusia edwardsii (N.R.Crouch & Mart.-Azorín) Mart.-Azorín et al. from Crouch & Martínez-Azorín (2015: 139, as Drimia edwardsii N.R.Crouch & Mart.-Azorín).

FIGURE 77. Species of Zulusia Mart.-Azorín et al. displayed in horizontal rows of images. 1. Zulusia delagoensis (Baker) Mart.-Azorín et al.; 2. Zulusia edwardsii (N.R.Crouch & Mart.-Azorín) Mart.-Azorín et al.; 3. Zulusia lydenburgensis (R.A.Dyer) Mart.-Azorín et al.