Diplusodon rotatus T.B. Cavalc., 2015

Cavalcanti, Taciana B., 2015, New species in Diplusodon (Lythraceae) from Brazil, Phytotaxa 226 (2), pp. 144-156 : 145-147

1. Diplusodon rotatus T.B. Cavalc. , sp. nov.

Type:— BRAZIL. Maranhão: Balsas, Lote 19, na descida da escarpa-Agrovila Nova de Carli, 8º41’39”S, 46º45’45”W, 4 August 1998 (fl.), Oliveira et al. 1245 (holotype CEN!, isotypes CEN!, HEPH!). Figures 1 , 2 .

Species characterized by shrubby habit with minute indumentum throughout the plant, vegetative leaf different from the bracts, oval bracts with domatia, little flowers with 12 stamens, epicalyx segments evident, longer than sepals, spread horizontally and prophylls positioned on the upper third of the pedicel.

Shrubs 1–1.5 m tall. Branches lax, the uppermost delicate, rust to wine-colored, cylindrical compressed, unwinged, minutely pubescent, internodes 12–16 cm long. Leaves light green, decussate, not imbricate, suberect, chartaceous, petiolate, not discolorous, light green when dry, acrodromous-basal-supranumerary; petiole 1.5–2 mm long, thick; blades 20–35 × 12–19 mm, oblong to ovate, base retuse, apex obtuse, acuminate, margin plane to slightly subrevolute, ciliate with short trichomes, adaxial surface minutely pubescent to glabrescent, abaxial surface minutely pubescent; veins 2 or 3 on each side of the midvein, 2 departing near the base of the midvein, sulcate on the adaxial surface, slightly prominent on the abaxial surface; domatia absent. Synflorescence frondose, pleiobotryum type, branches rust colored, thin, delicate, lax; principal florescence truncate; paraclades of the first and second order 15–30 cm long; paraclades of the third order 4–7 cm long; bracts oval to elliptic, spreading to suberect, base retuse to slightly subcordate, margin plane to slightly subrevolute, pubescent, ciliate with short trichomes, apex obtuse, slightly acuminate, veins 2 or 3 on each side of the midvein, with domatia; flowers pedicelate, hypopodium ca. 1.5 mm long, epipodium ca. 0.5 mm long; prophylls 4–4.6 × 1.2–2 mm, inserted on the upper third of the pedicel, surpassing the apex of the floral tube, narrowly elliptic, unkeeled, base attenuate, apex acute, margin plane, minutely pubescent; floral tube 4.2–4.5 mm long, delicate, funnel-shaped, with minute trichomes; sepals 2–2.5 mm long, triangular, not caudate, not deflexed, with minute trichomes; epicalyx segments 4–4.1 mm long, fine, cylindrical, spreading, longer than the sepals, with minute, spiky trichomes; corolla 2–2.5 cm in diam., rose, petals 9–10 × 5–7 mm, obovate, apex obtuse; stamens 12, free portion of the filaments ca. 5 mm long, slightly exserted; ovary 2–2.4 × 2.2–2.9 mm, obovate, glabrous, style 7–8 mm long, ovules 10–12. Capsules 3.6–4 × 3.5–4 mm, globose to oblong, glabrous; seeds 3 or 4, 2.5–2.9 × 2–2.1 mm.

Distribution and ecology:— Diplusodon rotatus is a rare species found in cerrado, sensu stricto, with rocky soil, at 200– 447 m. Flowers from June to August; fruits October to January. Etimology:—Specific epithet related to epicalyx segments horizontally spreading around the floral tube. Paratypes:— BRAZIL. Maranhão: Carolina, BR 010-Balneário, ca. 500m da pista em estrada de terra, 7 o 1’3’’S, 47 o 27’27’’W, 19 October 2013 (fr.), Cavalcanti & Pereira-Silva 3780 ( CEN!, MO!, NY!, UFMA!, W!); Carolina, estrada BR 010-Balneário Encontro das Águas, km 1, área de influência indireta, 7 o 21’3’’ S, 47 o 27’46’’ W, 19 January 2010 (fr.), Pereira-Silva & Moreira 14965 ( CEN!, HUEFS!, SP!).

Comments:— Diplusodon rotatus is a tall shrub which loses its vegetative leaves during flowering. In this case, the vegetative leaves are much larger than the bracts, and are not present on the plant at the same time. The vegetative leaves in D. rotatus are oblong and without domatia, while the bracts are oval with domatia, which can cause problems of identification. Diplusodon rotatus is characterized by the presence of minute indumentum throughout the plant, flowers with 12 stamens, epicalyx segments evident, strongly spreading and prophylls positioned on the upper third of the pedicel. The inflorescence is delicate with small flowers.

Figures

FIGURE 1. Diplusodon rotatus (A–E from Oliveira et al. 1245). A, branch with inflorescences. B, detail of a branch. C, leaf, adaxial surface. D, leaf, abaxial surface. E, flower with prophylls, without petals.

FIGURE 2. Diplusodon rotatus. Branch with fruits (author of the photograph: T.B. Cavalcanti; voucher Cavalcanti & Pereira-Silva 3780).