Diplusodon micromerus T.B.Cavalcanti, 2011

Cavalcanti, Taciana B., 2011, New taxa in Diplusodon (Lythraceae) from Brazil, Phytotaxa 38, pp. 29-35 : 33-35

Diplusodon micromerus T.B.Cavalcanti , sp. nov. ( Fig. 3 ).

Ab generis speciebus omnibus epicalycis segmentis prophyllisque valde redactis, foliis basibus cordatis, trichomatibus albis ornatis, acrodromisque, inflorescentiis congestis, floribus 18 staminibus praeditis distinguitur. A Diplusodon cordifolio foliis oblongis vel lanceolatis eucamptodromisque, tubo florali appendiculato, appendicibus usque ad 2 mm longis differt.

Type: BRAZIL. Goiás: Cavalcante, caminho para cachoeira Santa Bárbara , 20 April 2003 (fl), Pastore et al. 466 (holotype CEN!, isotypes K!, MO!, SPF!, W!) .

Subshrub ca. 35 cm tall, much-branched, congested. Upper branches cylindrical, non-winged, densely hirsute, whitish, internodes 0.5–0.8 cm long. Leaves sessile, blades 4–6 × 3–6 mm, orbicular to ovate, base cordate ovate, apex obtuse, canescent, decussate, not imbricate, suberect, strongly congested, coriaceous, discolorous, acrodromous supra-numerary, margin strongly revolute; veins 3–4 on each side of midvein, adaxial surface hirsute-sericeous, green-grayish, with deeply sulcate veins, abaxial surface hirsute-sericeous, white, with prominent veins; domatia absent. Inflorescence a compound raceme, frondose, congested; accessory branches absent, lateral branches 3–10 cm long; bracts similar to the cauline leaves in shape and size; flowers sessile, hypopodium and epipodium absent; prophylls ca. 5 × 3.8–3.9 mm, reaching to the apex of the floral tube, obovate, unkeeled, margin plane; floral tube ca. 4 mm long, funnel-shaped, densely covered with silvery trichomes, turning the floral tube shiny; sepals 2.0– 2.5 mm long, triangular, not caudate, not deflexed, densely covered with silvery trichomes; epicalyx segments 0.0– 0.5 mm long, shorter than the sepals, cylindrical, spreading, sericeous; corolla ca. 1.5 cm in diam., lilac, petals ca. 12 × 6.5 mm, elliptic, apex obtuse; stamens 18, free portion of the filaments ca. 6 mm long, shortly exserted; ovary obovoid, glabrous, ca. 1.9 × 1.8 mm, style ca. 11 mm long, ovules ca. 13. Fruits not seen.

Distribution and ecology:— Diplusodon micromerus is only known from the type collected in Chapada dos Veadeiros, Goiás, in Cerrado vegetation. It flowers in April.

Etymology:— The specific epithet was chosen to emphasize the diminutive floral parts of this species.

IUCN red List category:— The conservation status of IUCN Red List is estimated as “CRB2a” based on area of occupancy estimated to be less than 10 km ² and known to exist at only a single location (microendemic species).

Discussion:— Shrubs densely branched, with congested, discolorous, small leaves with a white abaxial surface. The flowers are congested on the branches, small, hidden by the bracts, and the floral tube and sepals are white, densely hirsute. The epicalyx segments are absent or inconspicuous, and the prophylls reach the apex of the floral tube. Diplusodon cordifolius is closely allied to D. micromerus , but differs from it by an oblong to lanceolate leaf shape, eucamptodromous venation with 2–3 lateral veins and evident domatia and epicalyx segments ca. 2 mm long that have sparsely spreading hairs.

Figures

FIGURE 3. Diplusodon micromerus A. branch. B. leaf, adaxial surface. C. leaf, abaxial surface. D. flower with prophylls, without petals. (A–D from Pastore et al. 466). Illustrated and inked by Taciana Cavalcanti.