Monotagma exile Hagberg & R.Erikss., 2011

Hagberg, Mats & Eriksson, Roger, 2011, New names in Monotagma (Marantaceae), Phytotaxa 20 (1), pp. 1-25 : 8-10

3. Monotagma exile Hagberg & R.Erikss. , sp. nov. ( Fig. 2D )

Monotagmatis juruani similis, sed ab eo differt foliorum laminis angustissime ellipticis apicibus rectis (vs. anguste ovatis apicibus obliquis), bracteis brevioribus (1.8–2.5 vs. 2.9–3.8 mm), ad anthesin patentibus (vs. imbricatis).

Type:— BRAZIL. Amazonas : Basin of Rio Purus. Rio Cunhuá at Canaça (6°34' S - 66°27' W), 27 November 1971, Prance et al. 16384 (holotype INPA, isotypes GB, K, L, NY) .

Herb 0.4–0.6 m tall. Rhizomes subterraneous, branched to form clusters of up to ca 5 shoots, each shoot bearing 3–6 distichous basal leaves. Ultimate basal leaf with sheath 10–16 cm long, ± chartaceous, puberulent to hirsute throughout, hairs sometimes appressed, rarely glabrous, auriculate; petiole 8–20 cm long, laterally ± flattened, with an adaxial furrow, glabrous; pulvinus 0.5–1.6 cm long, laterally ± flattened, puberulent adaxially, usually without annulus; blade usually very narrowly oblong, ± chartaceous when dry, base cuneate to obtuse, apex acuminate, ± centric (apex displacement 0–0.2 cm), 19–28 × 4.2–6.8 cm, length from base to broadest part 7–12 cm, adaxial surface usually not papillose, puberulent to appressed-puberulent along midrib and major lateral veins, and at apex, abaxial surface not papillose, glabrous or puberulent to appressedpuberulent at apex. Synflorescence 2–3-nodate with 3–4 florescences, lowermost node with a bladeless sheath, 2.3–4.2 cm long, or with a well-developed leaf, sheath 3.2–6.8 cm long, petiole 1.1–5.6 cm long, blade 15–20 × 3.7–5.4 cm, each subsequent node with a bladeless sheath, first internode 1.4–3.9 cm long, peduncle 9–24 cm long, ± glabrous. Main florescence 5–13 cm long, with 5–11 ± distichous bracts, first internode 0.9– 2 cm long, peduncle 1.4–2.1 cm long; lowermost bract 1.8–2.5 × 0.8–1 cm, greenish to brownish, glabrous or rarely appressed-puberulent at apex and along margins; first prophyll 12–15 mm long, glabrous or hirtellous on back and at apex, ecarinate; interphylls and bracteoles absent. Flowers 5–6 per bract, white; pedicel 1–2 mm long; ovary 1–2 mm long, glabrous or puberulent apically; sepals 9–11 × 1–2 mm; corolla tube 15–17 × ca 1.5 mm, outside hirsute above sepals, inside hirsute except for a glabrous basal portion or at least hirsute in mouth, lobes 5–5.5 × 2–3 mm; outer staminode ca 6 × ca 2 mm, narrowly oblong; stamen 2.5–5 mm long, appendage tapering to base of theca, theca 0.5–1.5 mm long; callose staminode 3–6 × 3–4 mm, fleshy throughout, with a shelf-shaped callus at 1.5–2.5 mm from apex; cucullate staminode 4–4.5 mm long, lateral appendage 0.5–1.5 mm long; style 3–4 mm long (tripped). Capsule 11–14 × ca 3 mm; seed 10–13 × 2.5–3 mm; aril 1–2 mm long, with two flattened unilateral lobes.

Distribution:—The lowlands of French Guiana and Amazonian parts of Brazil and Colombia.

Discussion:— Monotagma exile is most similar to M. juruanum , from which it differs by having leaf blades that are very narrowly elliptic and ± centric (vs. narrowly ovate and oblique), shorter bracts (1.8–2.5 vs. 2.9–3.8 cm), and by having bracts spreading at anthesis (vs. remaining imbricate).

Paratypes:— COLOMBIA. Amazonas: Río Loreto-Yacu , November 1946, Black & Schultes 325 (US) . BRAZIL. Pará: Cuiabá–Santarém road, km 1203, November 1977, Silva et al. 251 ( L, MG, NY). FRENCH GUIANA. Crique Noucir, affl. of the Oyapock, December 1983, Cremers 8321 ( CAY, GB); Crique Kapiri, basin of Approuague River , January 1991, Cremers 11626 ( CAY, GB, NY, P); Montagnes de Kaw , November 1985, de Granville 8242 ( CAY, GB); November 1987, de Granville 10203 ( B, CAY, GB, L, NY, P, US); Crique Solitaire, Montagnes de Kaw , December 1986, de Granville 9080 ( CAY, GB, P); Crique Gabaret, affl. of the Oyapock, December 1978, Grenand 1748 ( CAY, GB); Crique Sikini, Fleuve Oyapock, July 1969, Oldeman 2591 ( CAY, P); Régina– St. Georges road, basin of Approuague, April 1991, Cremers & Gautier 11953 ( CAY, GB) .

Doubtful specimens:— BRAZIL. Amazonas : Benjamin Constant , Igarapé Koyari , S of Tabatinga, March 1986, Andersson & Hagberg 1811 ( GB, INPA, S); Benjamin Constant, ca 3 km on trail towards Cruzeiro do Sul, March 1986, Andersson & Hagberg 1829 ( S). These two collections differ from the others by having oblique leaf blades and ± spathulate outer staminodes .

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).