Striatula M.Pinter, Mart.-Azorín, M.B.Crespo & Wetschnig

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 : 96-97

22. Striatula M.Pinter, Mart.-Azorín, M.B.Crespo & Wetschnig

in Phyton (Horn, Austria) 59: 93 (2019) ( Fig. 55 ).

Typus generis:— S. platyphylla (B.Nord.) M.Pinter, Mart.-Azorín, M.B.Crespo & Wetschnig (holotype).

Description:—Small bulbous geophyte. Bulb hypogeal, solitary, subglobose to ovoid, 1.5−4.0 cm in diam., outer tunics pale-brownish to brownish when drying, membranous, adherent, forming distinct neck, inner tunics whitish, compact, soft and fleshy. Roots thickened and branched. Leaves 1−2 per bulb, proteranthous, flattened, ovate to elliptic to elliptic-oblong, 1–4 cm long, appressed to ground, proteranthous, fleshy or subsucculent, dull or dark green, with 2 or 4 longitudinal furrows, minutely and densely velutinous on adaxial side, glabrous on abaxial side, with obtuse to rounded apex. Inflorescence 1(–2) per bulb, erect, racemose, 1.5−12.0 cm long, moderately dense, with 4–50 flowers; peduncle 3−15(−30) cm long, usually reddish brown or purplish red at base with dense and short to minute papillae or hairs disposed in straight vertical lines; pedicels patent or erecto-patent to spreading, 3−10 mm long, minutely scabridpapillate or glabrate. Bracts ovate-triangular to lanceolate, 1.0− 2.5 mm long, lowermost with distinct spur, 1−2 mm long; bracteoles absent. Flowers shallowly campanulate, urceolate or subglobose, nodding to subpatent. Tepals 6, 3.5–6.0 mm long, basally connate for ¼ to ½ of their length, reddish brown to creamy pink or pinkish white with broad purplish to green or greenish median stripe visible on both sides. Stamens 6, included in perigone, erect and connivent to style; filaments adnate to tepals for less than 1 mm, free parts 1.0− 1.5 mm long, whitish, laxly papillate-puberulous or smooth; anthers ellipsoid or ovate-sagittate, 1.0− 1.8 mm long, yellow, dehiscing with apical pore-like slits up to ½ of theca length, sometimes basally barbellate. Ovary ovoid to subquadrate, 1.8−2.0 mm long, light green, glabrous. Style columnar, erect, terete, 1.0− 1.8 mm long, white. Capsule broadly ovoid to subglobose, 4.5–7.0 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 elliptic-oblong to reniform, 2–4 mm long, flattened, with prominent embryo and short, wings, with black, glossy testa and alveolate-reticulate testa cells with collapsed periclinal walls and prominent anticlinal walls.

Number of species and distribution:— Striatula includes 2 species from the Western Cape, Eastern Cape, and Northern Cape Provinces of South Africa and southern Namibia ( Fig. 49 ), being restricted to the Cape and Karoo-Namib Regions and the Southern Section of the Zambezian Subregion (sensu Takhtajan 1986 and Martínez-Azorín et al. 2023a). For complete morphological descriptions of the two taxa see Nordenstam (1970) and Manning & Oliver (2009).

Karyology:—2n=20 ( Bruyns & Vosa 1987, as Rhadamanthus platyphyllus B.Nord.).

History, diagnostic characters, and taxonomic relationships:— Nordenstam (1970) described Rhadamanthus platyphyllus , a species sharing the general flower morphology and anther dehiscence of that genus, but differing in having two, flat, ovate, velutinous leaves with longitudinal furrows, which are appressed to the ground and the anthers basally barbellate with spine-like or papilliform outgrowths, whilst the remaining species of Rhadamanthus sensus Nordenstam (1970) show numerous, filiform, erect leaves. Drimia oliverorum was described from southern Namibia and shares the peculiar leaf morphology and flower structure of R. platyphyllus . The phylogenetic analyses of Pfosser et al. (2012) showed that seven samples of the Rhadamanthus platyphyllus group formed a perfectly supported clade, which is located far from the clade including other Rhadamanthus species, the latter being basal to all Urgineoideae when Bowiea is excluded. The clear phylogenetic divergence of both R. platyphyllus and D. oliverorum , together with their distinct vegetative morphology led Pinter et al. (2019) to described Striatula to accommodate these two taxa, a solution followed in the present work. The phylogenetic studies by Martínez-Azorín et al. (2023a) confirmed the results by Pfosser et al. (2012) and include 12 samples of Striatula , which form a perfectly supported clade in an isolated position within Urgineoideae . This genus can be easily identified by its unique syndrome of morphological characters, and is restricted to southern and western South Africa and southern Namibia.

Accepted species:—

Striatula oliverorum (J.C.Manning) M.Pinter, Mart.- Azorín, M.B. Crespo & Wetschnig in Phyton (Horn, Austria) 59: 95 (2019) ≡ Drimia oliverorum J.C.Manning in Manning & Oliver in Bothalia 39(2): 225 (2009), basionym ( Figs 4.17 , 55.1 ). Type:— NAMIBIA. Witputz (2716): Huib Hoch Plateau, Zebrasfontein, (–DB), elev. 1200 m, 29 June 1989 [in leaf only], E.G.H. Oliver & I.M. Oliver 9164 (NBG0233338-0! holo.).

Striatula platyphylla (B.Nord.) M.Pinter, Mart.-Azorín, M.B.Crespo & Wetschnig in Phyton (Horn, Austria) 59: 95 (2019) ≡ Rhadamanthus platyphyllus B.Nord. in Taxon 63(6): 1332 (2014), basionym ≡ R. platyphyllus B.Nord. in Bot. Not. 123: 172 (1970), nom. inval. ≡ Drimia platyphylla (B.Nord.) J.C.Manning & Goldblatt in Strelitzia 40: 132 (2018) ≡ D. platyphylla (B.Nord.) J.C.Manning & Goldblatt in Strelitzia 9: 712 (2000), nom. inval. ( Figs 4.18 , 55.2 ). Type:— SOUTH AFRICA. Western Cape. Wuppertal (3219): Clanwilliam Div., in stony or shallow sand on rocky slope below shale band below Cederberg Tafelberg, (–AC), elev. 3500–4000 ft., 16 December 1950, Esterhuysen 18135, leaves added April 1951 (BOL140333! holo.: the bulb with two leaves at the bottom left hand side corner of the sheet).

Figures

FIGURE 4. Seed morphology in Urgineoideae. 1. Rhodocodon rotundus H.Perrier ex Knirsch et al.; 2. Rhodocodon siederi Knirsch et al.; 3. Rhodocodon urgineoides Baker; 4. Schizobasis intricata (Baker) Baker; 5. Schizobasis macowanii Baker; 6. Schizobasis sigmoidea (J.C.Manning & J.M.J.Deacon) Mart.-Azorín et al.; 7. Sekanama brachystachys (Baker) Mart.-Azorín et al.; 8. Sekanama porphyrostachys (Baker ex Balf.f.) Mart.-Azorín et al.; 9. Sekanama sanguinea (Schinz) Speta; 10. Squilla hesperia (Webb & Berthel.) Mart.-Azorín et al.; 11. Squilla maritima (L.) Steinh.; 12. Squilla palaestina (M.B.Crespo et al.) Mart.-Azorín et al.; 13. Squilla pancration Steinh.; 14. Squilla secundiflora (Maire) Mart.-Azorín et al.; 15. Squilla serotina (Schousb.) Mart.-Azorín et al.; 16. Squilla undulata (Desf.) Mart.-Azorín et al.; 17. Striatula oliverorum (J.C.Manning) M.Pinter et al.; 18. Striatula platyphylla (B.Nord.) M.Pinter et al.; 19. Tenicroa exuviata (Jacq.) Speta; 20. Tenicroa fragrans (Jacq.) Raf. All to the same scale in mm.

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

FIGURE 55. Species of Striatula M.Pinter et al. displayed in horizontal rows of images. 1. Striatula oliverorum (J.C.Manning) M.Pinter et al.; 2. Striatula platyphylla (B.Nord.) M.Pinter et al.