Tenicroa Raf., Fl. Tellur.

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 : 97-102

23. Tenicroa Raf., Fl. Tellur.

3: 52 (1837) ( Figs 56–59 ). Typus generis:— Tenicroa fragrans (Jacq.) Raf. ≡ Anthericum fragrans Jacq. ≡ Drimia fragrans (Jacq.) J.C.Manning & Goldblatt (holotype).

= Pilasia Raf., Fl. Tellur. 3: 53 (1837). Typus generis:— P. filifolia (Jacq.) Raf. ≡ Anthericum filifolium Jacq. ≡ Tenicroa filifolia (Jacq.) Oberm. ≡ Drimia filifolia (Jacq.) J.C.Manning & Goldblatt (holotype).

= Sypharissa Salisb., Gen. Pl. [Salisbury]: 37 (1866) ≡ Urginea sect. Sypharissa (Salisb.) Baker in J. Linn. Soc., Bot. 13: 216 (1873) ≡ Drimia sect. Sypharissa (Salisb.) J.C.Manning & Goldblatt in Strelitzia 40: 111 (2018). Typus generis:— S. exuviata (Jacq.) Salisb. ex Oberm. ≡ Anthericum exuviatum Jacq. ≡ Tenicroa exuviata (Jacq.) Speta ≡ Drimia exuviata (Jacq.) Jessop (lectotype designated by Obermeyer in Bothalia 13: 111. 1980).

= Drimia sect. Juncifoliae J.C.Manning & Goldblatt in Strelitzia 40: 107 (2018). Typus sectionis:— D. juncifolia J.C.Manning & J.M.J.Deacon ≡ Tenicroa juncifolia (J.C.Manning & J.M.J.Deacon) Mart. -Azorín et al. (holotype).

Description:—Medium-sized bulbous geophyte. Bulb hypogeal, ovoid to subglobose, up to 7 cm in diam., extended into neck surrounded by cataphylls with raised, transverse purple to brown ribs, inner scales white to pinkish, fleshy, compact or rarely loose, spirally arranged, rarely distichous, sometimes fibrose.Roots distinctly thickened and branched. Leaves 1‒50 per bulb, 3‒80 cm long, narrowly linear, from terete to channelled, synanthous or rarely hysteranthous, entire or rarely scabrid on margins, green or somewhat glaucous, usually leathery, sometimes twisted, smooth, glabrous. Inflorescence a long, erect, multiflowered raceme, 2‒25 cm long, with up to 60 flowers; peduncle 10‒40 cm long, green, grey or purple, terete, erect, smooth and glabrous; pedicels 3‒15 mm long, shorter than tepals at anthesis, spreading in flower and erect in fruit. Bracts narrowly lanceolate, long acuminate, lowermost auriculate with long spur, sometimes bifid or branched and sinuous; bracteoles absent. Flowers stellate with patent tepals, diurnal. Tepals 6, biseriate, 6‒17 mm long, free, ovate-lanceolate to elliptic, white with well defined, narrow, purplish longitudinal band. Stamens 6, suberect and slightly spreading; filaments filiform, 4‒8 mm long, tapering, smooth, white, slightly sigmoid and curving distally; anthers yellow, erect, basifixed, deshicing longitudinally along their whole length, with yellow pollen. Ovary ovate-oblong, green to yellow. Style 4‒8 mm long, declinate, sigmoid, white or rarely tinged with purple, with capitate, papillose stigma. Capsule ovate to ellipsoid, 6‒25 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 subellipsoid to compressed, (4–) 5‒11 mm long, flattened, embryo prominent with wide or short wings, testa black, dull or glossy, with sinuous cell walls.

Number of species and distribution:— Tenicroa includes twelve species restricted to southern and western South Africa and southern Namibia, it being therefore restricted to the Cape and Karoo-Namib Regions (sensu Taktajan 1986) ( Fig. 49 ). For complete species characteristics see Pinter et al. (2020).

Karyology:—2n=20 ( Speta 1998a).

History, diagnostic characters, and taxonomic relationships:— Rafinesque (1837) described Tenicroa to include T. fragrans ( Jacquin 1797: t. 86) Rafinesque (1837: 53), a species with rotate flowers, suberect stamens and deflexed style, among other characters. The revision by Obermeyer (1980b, 1981a) accepted four species in the genus from southern and western South Africa and southern Namibia: T. fragrans , T. exuviata (Jacquin 1794: 18) Speta (1980: 195) , T. filifolia (Jacquin 1794: 18) Obermeyer (1981a: 577) , and T. multifolia (Lewis: 1952: 9) Obermeyer (1981a: 577). All of them shared distinct characters such as the synanthous leaves surrounded by sheathing cataphylls that are markedly striate with raised, dark, transversal ridges; the stellate flowers with almost free tepals with a narrow, longitudinal dark band on the abaxial side; the suberect to slightly spreading stamens with basifixed anthers and the elongate, deflexed and curved style; and papillate stigma. Despite the distinct morphology of taxa in this genus, they have historically been placed in 8 different genera: Anthericum Linnaeus (1753: 310) , Albuca , Drimia , Ornithogalum , Phalangium Miller (1754 : s.n.), Pilasia Rafinesque (1837: 53) , Sypharissa Salisbury (1866: 37) , and Urginea , representing a good example of the uncertainty in taxonomy and systematics of urgineoid taxa ( Pinter et al. 2020). However, based on the clear synapomorphies of Tenicroa , researchers in Urgineoideae ( Jessop 1977, Obermeyer 1980b, 1981a, Speta 1998a, 1998b) usually recognised it as a distinct genus. Conversely, Manning et al. (2004) synonymised Tenicroa to Drimia sensu lato, and later Manning & Goldblatt (2018) placed the Tenicroa species recognised by Obermeyer (1980b) in D. sect. Sypharissa , whilst including T. filifolia as synonym of T. exuviata . They also separated their new D. sect. Juncifoliae to associate two newly described species [ Drimia decipiens Manning & Goldblatt (2018: 109) and D. juncifolia J.C.Manning & J.M.J.Deacon in Manning & Goldblatt (2018: 107)] based on their hysteranthous leaves, weakly barred cataphylls, and medifixed anthers that are not deflexed. Martínez-Azorín et al. (2019a) considered the latter distinction insufficient to recognise both sections, and transferred the two new species to Tenicroa .

The phylogenetic analyses of Manning et al. (2004) recovered two samples of Tenicroa as monophyletic, when excluding T. nana as the monotypic Mucinaea ( Pinter et al. 2013) . Pfosser et al. (2012) phylogenetically analysed nine samples of Tenicroa that formed a perfectly supported clade being sister to a clade comprising Litanthus plus Schizobasis . Furthermore, the phylogenetic analyses of Martínez-Azorín et al. (2023a) included 21 samples of Tenicroa , which formed a strongly supported and isolated clade within a large polytomy. Therefore, we here accept Tenicroa at genus rank based on the unique syndrome of morphological characters and its isolated phylogenetic position, following the latest revision of Tenicroa by Pinter et al. (2020), who accepted twelve species restricted to South Africa and southern Namibia.

Accepted species:—

Figures

FIGURE 49. Approximate distribution ranges of accepted genera in Urgineoideae.

FIGURE 56. Species of Tenicroa Raf. 1. Tenicroa fragrans (Jacq.) Raf. from Jacquin (1797: t. 86, as Anthericum fragrans Jacq.); 2. Tenicroa exuviata (Jacq.) Speta from Jacquin (1794: t. 415, as Anthericum exuviatum Jacq.); 3. Tenicroa filifolia (Jacq.) Oberm. from Jacquin (1794: t. 414, as Anthericum filifolium Jacq.); 4. Tenicroa filifolia (Jacq.) Oberm. from Ker Gawler (1821: t. 557, as Albuca filifolia (Jacq.) Ker Gawl.).

FIGURE 57. Species of Tenicroa Raf. 1. Tenicroa exuviata (Jacq.) Speta from Ker Gawler (1805: t. 871, as Albuca exuviata (Jacq.) Ker Gawl.); 2. Tenicroa fragrans (Jacq.) Raf. from Ker Gawler (1818: t. 311, as Albuca fugax Ker Gawl.); 3. Tenicroa multifolia (G.J.Lewis) Oberm. from Lewis (1952: 10, as Urginea multifolia G.J.Lewis).

FIGURE 58. Species of Tenicroa Raf. displayed in horizontal rows of images. 1. Tenicroa applanata M.Pinter et al.; 2. Tenicroa exuviata (Jacq.) Speta; 3. Tenicroa fibrosa M.Pinter et al.; 4. Tenicroa filifolia (Jacq.) Oberm.

FIGURE 59. Species of Tenicroa Raf. displayed in horizontal rows of images. 1. Tenicroa fragrans (Jacq.) Raf.; 2. Tenicroa multifolia (G.J.Lewis) Oberm.; 3. Tenicroa namibensis M.Pinter et al. (Photographs of bulb with leaf by H. Kolberg and in flower by A. Burke); 4. Tenicroa polyantha M.Pinter et al.; 5. Tenicroa unifolia (A.V.Duthie) M.Pinter et al.