Sagina diffusa, Timaná, 2018

Timaná, Martín E., 2018, Sagina diffusa (Hook. f.) Timaná, comb. nov. (Caryophyllaceae), a new combination for the flora of Île St. Paul (Southern Indian Ocean), with some historical notes, Adansonia (3) 40 (3), pp. 47-53 : 50

Sagina diffusa (Hook.f.) Timaná, comb. nov.

( Fig. 1 )

Colobanthus diffusus Hook. f., Botany of the Antarctic Voyage , vol. I, Flora Antarctica 2: 249 (1845). — Typus: “Île Amsterdam” [Île Saint Paul], Staunton s.n., s. dat. (1 or 2.II.1793). — Lectotype (designated here), BM! ( BM 000513207 ). The sheet carries an underside annotation: “Island of Amsterdam. Sir Geo. Staunton”. — Syntype: “Île Amsterdam” [Île Saint Paul], Lieut. A J. Smith s.n., s.dat. (VIII.1844?), reported to be at K, would presumably be a syntype, but verification was not possible because the specimen could not be located.

Sagina hochstetteri Reichardt, Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 21: 34 (1871), nom. illegit. — Typus: “Île Amsterdam” (Île Saint Paul), Staunton s.n., 1 or 2.II.1793 (W, destroyed); F. von Hochstetter s.n., s.dat. (7.XII.1857) (W, destroyed).

DESCRIPTION

Diffuse, loosely spreading herb; branches filiform, sometimes slightly angular, glabrous, 5-8 cm long.Leaves opposite, spreading along the main axis; rosette leaves lacking; lower cauline leaves 4-9 mm long, 0.4-0.7 mm wide; upper cauline leaves 6-7 mm long, (0.3) 0.5-1 mm wide; leaves sessile, blade basally connate forming a shallow, scarious cup; apex mucronate; blade glabrous. Inflorescence single-flowered, pedicel filiform, c. 8-10 mm long, upright, glabrous. Flowers bisexual, paired, terminal or axillary, bracts paired, foliaceous, c. 1.6 mm long. Calyx cymbiform, sepals 4 or rarely 5, ovate, apex acute to obtuse, 1.6-1.8 mm long, glabrous, margin hyaline, appressed at the time of capsule maturity. Petals 4 or 5, alternisepalous, ovate to elliptic, apex acute to obtuse, 1.2-1.4 mm long, 0.6- 0.7 mm wide, thin, hyaline. Stamens (4)5(6), episepalous; filament 1.2-1.4 mm long, slightly enlarged toward the base, anthers dorsifixed.Pistil ovoid, c. 1.5 mm long, stigmatic lobes as many as sepals. Fruit capsule, opening lengthwise by 4 or rarely 5 valves, opposite to sepals, 2.5-2.7 mm long, longer than sepals. Seeds reniform, dark brown.

Figures

FIG. 1. — Lectotype (BM 000513207) of Sagina diffusa (Hook.f.) Timaná, comb. nov. Reproduced by permission, ©The Natural History Museum, London, U.K.