Diplusodon venosus T.B. Cavalc., 2015

Cavalcanti, Taciana B., 2015, New species in Diplusodon (Lythraceae) from Brazil, Phytotaxa 226 (2), pp. 144-156 : 149

3. Diplusodon venosus T.B. Cavalc. , sp. nov.

Type:— BRAZIL. Goiás: Cavalcante, entroncamento Minaçú-Kalunga (Engenho Dois), km 5, 13º36’06”S, 47º28’29”W, 31 August 2004 (fl., fr.), Cavalcanti et al. 3534 (holotype CEN!; isotype SPF!). Figure 4 .

Species characterized by the upper branches straw-colored, leaf blades 50–70 × 6–26 mm, very distinct from bracts (1–4 mm wide), long bracteose inflorescence and flowers with 18–24 stamens.

Subshrubs 0.35–0.7 m tall, glabrescent, foliage lax. Branches slightly quadrangular and flattened, with an inconspicuous wing, the upper branches straw-colored, with minute and very inconspicuous trichomes to glabrous, internodes 3–4.5 cm long. Leaves decussate, rarely verticillate, not imbricate, erect, coriaceous, subsessile, not discolorous, not glaucous, not dark brown when dry, eucamptodromous to acrodromous; petiole 0.5–1 mm long; blades 50.5–70 × 6–26 mm, narrow-elliptic or narrow-lanceolate to wide-elliptic, base obtuse to acute, apex acute, slightly acuminate, margin plane, irregular, with minute and inconspicuous cilia, blades glabrescent to glabrous, trichomes when present slightly bulbose at the base, sparse, common on the abaxial surface; veins 2 or 3 along the midvein, very prominent; domatia present, inconspicuous. Synflorescence bracteose, triplobotryum to pleiobotryum type, lax; accessory branches absent, principal florescence of the botryum type, usually truncate, paraclades 5–25 cm long; bracts 15–30 × 1–4 mm, glabrous, linear to narrow-elliptic; flowers short-pedicelate, hypopodium 0.5–1 mm long, epipodium to 0.5 mm long; prophylls 4–4.2 × 1.5–1.7 mm, surpassing the middle of the floral tube, almost reaching the apex of the floral tube, narrow-elliptic to obovate, keeled, base retuse to acute, apex acute, margin plane; floral tube 4.5–5 mm long, funnel-shaped, glabrous; sepals 2–2.2 mm long, triangular, not deflexed, glabrous; epicalyx segments ca. 2 mm long, slightly dorso-ventrally compressed, spreading, glabrous, shorter than the sepals; corolla 3.5–4 cm in diam., lilac to rose-magenta, petals 13–19 × 7–10 mm, obovate, apex obtuse; stamens 18–24, free portion of the filaments 6–6.5 mm long, slightly exserted; ovary 2–2.2 × 2.2–3 mm, obtrapezoidal, glabrous, style 7–10 mm long, ovules 22–42. Capsules 4.5–5 × 4–4.5 mm, globose, glabrous; seeds ca. 31, 1.5–2.2 × 1.5–2.8 mm.

Distribution and ecology:— Diplusodon venosus is known only from the municipality of Cavalcante in the vicinity of the traditional community Kalunga. It inhabits cerrado and fields on sandy soil with sandstones at 919–1,030 m. Flowers from March to July; fruits April to September.

Etimology:—Specific epithet related to conspicuously veined leaves.

Paratypes:— BRAZIL. Goiás: Cavalcante, aldeia Kalunga , 6 March 2003 (fl.), Pastore & Suganuma 444 ( CEN!) ; Cavalcante, estrada para Prata ( Kalungas ), 13º22’24”S, 47º41’9.1”W, Cavalcante , comunidade Kalunga , caminho para a cachoeira Capivara , 20 April 2003, (fl.), Pastore et al. 471 ( CEN!) ; Cavalcante, comunidade Kalunga , 20 April 2003, (fl.), Pastore et al. 473 ( CEN!) ; Cavalcante, estrada para Prata ( Kalungas ), 13º22’24”S, 47º41’9.1”W, 14 April 2004 (fl.), Fonseca et al. 5095 ( CEN!, HRB!, IBGE!) .

Comments:— Diplusodon venosus is another unusual species of the genus from the mountains of Goiás. The upper branches are straw-colored, the bracteose inflorescence is long, broad and conspicuous, with distinct linear to narrow-elliptic bracts different from the vegetative leaves, especially in size. The leaves are variable in width, ranging in shape from narrow-elliptic, narrow-lanceolate to wide-elliptic, but always with strongly prominent veins, also present on the bracts. Because of the bracteose inflorescence, the species resembles D. astictus Lourteig (1963: 6) and D. ramosissimus Pohl (1827: 151) , which also occur in the region. However, D. astictus has upper branches wine-colored to chestnut, and larger flowers with 12 stamens. In D. ramosissimus the leaves have conspicuous domatia and the flowers have very short prophylls, not reaching the middle of the floral tube.

Figures

FIGURE 4. Diplusodon venosus (A from Pastore & Suganuma 444; B–D from Pastore et al 473; E–H from Fonseca et al. 5095). A, section of vegetative branch with elliptic leaves. B, section of vegetative branch with narrow-elliptic leaves. C, branches with inflorescences. D, detail of a branch. E, bract, abaxial surface. F, flower with prophylls, without petals. G, prophyll, adaxial surface. H. stigma capitate.