Monotagma roseum Hagberg & R.Erikss., 2011

Hagberg, Mats & Eriksson, Roger, 2011, New names in Monotagma (Marantaceae), Phytotaxa 20 (1), pp. 1-25 : 11-12

6. Monotagma roseum Hagberg & R.Erikss. , sp. nov. ( Fig. 2G )

Bracteis roseis, foliis ad bases cordatis, et nodo inferiore synflorecentiae vagina tantum instructo Monotagmatis rhodanthi similis, sed ab eo differt foliis abaxiali pagina virella (vs. cerosa et glaucescenti) et laminarum costa ad apices attingentibus (vs. ad 2/3 laminae longitudine attingentibus).

Type:— BRAZIL. Pará: Rio Cururí, tributary of Rio Tapajos, region of village Pratatí , 300–400 m, 11 February 1974, Anderson et al. 10773 (holotype IAN, isotypes AAU, F, MO, NY, UPS) .

Herb up to ca 1.5 m tall. Rhizomes subterraneous, branched to form clusters of up to ca 5 shoots, each shoot bearing 2–3 ± irregularly arranged basal leaves. Ultimate basal leaf with sheath 12–36 cm long, chartaceous to subcoriaceous, puberulent throughout, auriculate; petiole 13–41 cm long, laterally ± flattened, without an adaxial groove, glabrous; pulvinus 0.5–1.3 cm long, laterally ± flattened, puberulent adaxially, annulus lacking; blade narrowly elliptic, ± coriaceous when dry, base slightly cordate, apex acuminate, ± centric, 14– 31 × 4.5–7 cm, length from base to broadest part 7–13 cm, adaxial surface not papillose, puberulent along margins and at apex, or rarely glabrous, abaxial surface not papillose, glabrous. Synflorescence 2–4-nodate with 5–15 florescences, each node with a bladeless sheath, lowermost one 2.9–6 cm long, first internode 0.7– 3.8 cm long, peduncle 50–160 cm long, glabrous. Main florescence 4–8 cm long with 10–23 ± unilaterally arranged bracts, first internode 0.3–0.5 cm long, peduncle 0.2–0.6 cm long; lowermost bract 1.5–1.8 cm long, pinkish, subchartaceous, glabrous; first prophyll 8–10 mm long, glabrous. Flowers 2–3 per bract; pedicel ca 1 mm long; ovary 1–1.5 mm long, glabrous; sepals 4.5–6.5 × 1–1.5 mm, apex obtuse; corolla tube 11–16 × ca 1 mm, outside glabrous, inside hirsute to hirtellous in mouth, rarely throughout except for a glabrous basal portion, lobes 3.5–5 × 2–3 mm, only slightly open, leaving a small pore at apex; outer staminode absent; stamen ca 3.5 mm long, appendage tapering to base of theca, theca ca 1.5 mm long; callose staminode 2.5–3.5 × 2.5–3.5 mm, ca 1 mm petaloid apically, with a shelf-shaped callus at ca 2.5 mm from apex; cucullate staminode 3–3.5 mm long, lateral appendage ca 1.5 mm long; style 2.5–3 mm long (untripped), or 2–3 mm long (tripped). Capsule 10–11 × 4–4.5 mm; seed 9–9.5 × 3.5–4 mm; aril ca 3 mm long, with 2 narrow and string-shaped, coiled lobes.

Distribution and habitat:—Southern Pará and adjacent parts of northern Mato Grosso; in sandy cerrado vegetation and along streams, at 300–400 m elevation.

Discussion:— Monotagma roseum is most similar to M. rhodanthum , from which it differs in having leaf blades that are greenish beneath (vs. waxy and glaucescent) and by the midribs reaching the leaf apex (vs. only 2/3 up the blade).

Paratypes:— BRAZIL. Mato Grosso: Rio Teles Pires , Posto dos Indios Caiabí, January 1952, Pires 3866 ( IAN) . Pará: Rio Cururí , affl. to Rio Tapajós, SE of Missão Cururú, February 1974, Anderson et al. 10616 ( AAU, F, LD, MO, NY, US) ; Missão Cururú , Rio Tapajos, July 1959, Egler 853 ( MG) .

Figures

FIGURE 2. Monotagma seeds (A–C), habits (D–E, G–H), and synflorescence (F). A, M. laxum (Hagberg et al. 330); B, M. rudanii (Hagberg et al. 331); C, M. tuberosum (Hagberg & Medin 362); D, M. exile (Cremers 8321); E, M. floribundum (Bamps 5222); F, M. paradoxum (Schunke 5739); G, M. roseum (Andersson 10616); H, M. septentrionale (Jangoux 10164).