Triandra Mart.-Azorín, M.B.Crespo, M.Á.Alonso, N.R. Crouch & M.Pinter

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 : 108-109

25. Triandra Mart.-Azorín, M.B.Crespo, M.Á.Alonso, N.R. Crouch & M.Pinter

in Phytotaxa 487(1): 66 (2021) ( Fig. 62 ).

Typus generis:— T. pellabergensis Mart. -Azorín, M.B.Crespo, M.Á.Alonso, N.R. Crouch & M.Pinter (holotype).

Description:—Small bulbous geophyte. Bulb hypogeal, ovoid to subglobose, 8‒18 mm in diam., with white, fleshy, compact, inner scales and pale brown, membranous outer tunics. Roots thickened and branched. Leaves 2‒6 per bulb, hysteranthous, 2‒8 cm long, filiform, to 1 mm in diam., subterete or very slightly flattened, green, smooth, glabrous. Inflorescence a lax, erect raceme, 2‒5 cm long, with 4–8 flowers; peduncle 4‒8 cm long, brownish, erect, terete, smooth; pedicels 7‒9 mm long, smooth, patent proximally and soon arching downwards distally at anthesis, curving upwards in fruit. Bracts ovate-lanceolate, small, ca. 0.5 mm long, lowermost with short spur, ca. 0.3 mm long, persistent; bracteoles absent. Flowers stellate, nodding, with strongly reflexed tepals at full anthesis with tips touching flower pedicel, nocturnal, opening in late evening and closing before sunrise, fragrant during night. Tepals 6, biseriate, 5‒6 mm long, narrowly oblong, slightly constricted along middle, obtuse, whitish to pale brown, with darker brownish longitudinal band more evident on abaxial side, almost free to very shortly connate for 0.5 mm. Stamens 3, only inner whorl present, outer absent with no basal rudiments, erect, straight, approaching ovary and style, with 3 anthers placed near stigma; filaments 3.5‒3.8 mm long, filiform, white, subterete, only slightly widened at base, connivent to style, free, not adnate to tepals; anthers oblong, ca. 0.6 mm long after dehiscence, subbasifixed, yellow to orange, with yellow polen. Ovary ovate, 1.9‒2.2 mm long, pale brown to yellowish. Style 2.0‒ 2.2 mm long, erect, white, filiform and narrow, ending in undifferentiated stigma. Capsule ovate, trigonous, 4‒5 mm long, pale brown, 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 ellipsoidal to broadly ellipsoid, flattened, 6‒16 mm long, testa black, glossy, with subpolygonal cells.

Number of species and distribution:—A monotypic genus originally described from a single locality on the Pella-se-Berge, northwestern South Africa, near to the border with Namibia, a locality included in the Karoo-Namib Region (sensu Takhtajan 1986) ( Fig. 49 ). Recently, Manning (2022) cited the collection Harrower 6188 (NBG) as the second known locality for this species occurring in the Pienaarsfontein-se-Berge, Koedoesberge near Touwsrivier, representing an extension of more than 400 km to the south, near the Tanqua Karoo in the Western Cape Province of South Africa. Two additional populations were found, in September 2015 in the Naib se Berg and in August 2022 in the Nouroepberge near Dabenoris Mountains, both in vegetative stage, by M. Martínez-Azorín & collaborators (MMA1269 ABH74121! and MMA2078 ABH74374! respectively). The phylogenetic analyses of these samples and their recent flowering in cultivation confirmed their placement in Triandra .

Karyology:— Not studied yet.

History, diagnostic characters, and taxonomic relationships:—Our field work in Southern Africa led to the discovery at the Pella-se-Berg (NW South Africa) of a small species of Urgineoideae with a remarkable morphology. The plants produce nocturnal, nodding flowers with most notably only three stamens per flower, a character not previously reported in Hyacinthaceae . This led Martínez-Azorín et al. (2021) to describe Triandra pellabergensis Martínez-Azorín et al. (2021: 68) —a new genus and species. The phylogenetic studies by Martínez-Azorín et al. (2023a) based on plastidial DNA sequences placed this species in an isolated position, sister to a clade comprising samples of Rhodocodon from Madagascar. Therefore, we accept Triandra to accommodate this outstanding species in the subfamily, which is supported by clear morphological, biogeographical, and molecular data ( Martínez-Azorín et al. 2023a).

Accepted species:—

Triandra pellabergensis Mart. - Azorín, M.B. Crespo, M.Á. Alonso, N.R.Crouch & M. Pinter in Phytotaxa 487: 68 (2021) ≡ Drimia pellabergensis (Mart. - Azorín, M.B. Crespo, M.Á. Alonso, N.R.Crouch & M.Pinter) J.C.Manning & Goldblatt in Bothalia 52(1): 3 (2022) ( Figs 5.8 , 62 ). Type:— SOUTH AFRICA. Northern Cape. Pofadder (2919): Pella , Pella se Berge , ca. 25 km W of Pofadder, rocky slopes at base of large south facing cliffs, (–AA), elev. 919 m, among quartz and mica rocks, fl. ex hort at University of Alicante on 29 June 2018, M. Martínez-Azorín, M.B. Crespo, M.Á. Alonso et al. MMA1671b (GRA! holo.; ABH!, K, PRE iso.).

Figures

FIGURE 5. Seed morphology in Urgineoideae. 1. Tenicroa multifolia (G.J.Lewis) Oberm.; 2. Tenicroa polyantha M.Pinter et al.; 3. Tenicroa unifolia (A.V.Duthie) M.Pinter et al.; 4. Thuranthos bakeri Mart.-Azorín et al.; 5. Thuranthos macrocarpum (Stedje) Speta; 6. Thuranthos nocturnale R.A.Dyer; 7. Thuranthos pauciflorum (Baker) Mart.-Azorín et al.; 8. Triandra pellabergensis Mart.-Azorín et al.; 9. Urginavia altissima (L.f.) Speta; 10. Urginavia capensis (Burm.f.) Mart.-Azorín et al.; 11. Urginavia echinostachya (Baker) Mart.-Azorín et al.; 12. Urginavia kniphofioides (Baker) Mart.-Azorín et al.; 13. Urginavia micrantha (A.Rich.) Speta; 14. Urginavia multisetosa (Baker) Mart.-Azorín et al.; 15. Urginavia simensis (Hochst. ex A.Rich.) Mart.-Azorín et al.; 16. Urginea fugax (Moris) Steinh.; 17. Urgineopsis arenosa (Adamson) Mart.-Azorín et al.; 18. Urgineopsis dregei (Baker) Mart.-Azorín et al.; 19. Urgineopsis exilis (Adamson) Mart.-Azorín et al.; 20. Urgineopsis gracilis (A.V.Duthie) Mart.-Azorín et al. All to the same scale in mm.

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

FIGURE 62. Triandra pellabergensis Mart.-Azorín et al.