Monotagma aurantispathum Hagberg & R.Erikss., 2011

Hagberg, Mats & Eriksson, Roger, 2011, New names in Monotagma (Marantaceae), Phytotaxa 20 (1), pp. 1-25 : 18-20

13. Monotagma aurantispathum Hagberg & R.Erikss. , sp. nov. ( Fig. 4A )

Differt a speciebus caeteris Monotagmatis spathis aurantiacis ad anthesin imbricatis. M. smaragdini et M. flavicomi similis , sed ab eis differt staminodio exteriore anguste elliptico (vs. spathulato) apice integro (vs. emarginato).

Type:— PERU. Loreto: Brillo Nuevo on Río Yaguasyacu, trib. to Río Ampiyacu , 8 November 1977, Gentry & Revilla 20389 (holotype MO, isotype GB) .

Herb 1–1.5 m tall. Rhizomes subterraneous, branched to form clusters of a few shoots, each shoot bearing up to ca 6 irregularly arranged basal leaves. Ultimate basal leaf with sheath 24–37 cm long, subchartaceous to chartaceous, hirsute throughout, not auriculate; petiole 0.4–12 cm long, laterally flattened, hirsute; pulvinus 0.5–0.7 cm long, ± terete, hirsute throughout, without annulus; blade narrowly elliptic, papyraceous when dry, base cuneate to obtuse, apex caudate, centric, 24–33 × ca 10 cm, length from base to broadest part 12–15 cm, adaxial surface ± papillose, hirsute throughout, abaxial surface not papillose, hirsute throughout. Synflorescence 2–3-nodate with 3–7 florescences, first and sometimes also second node with a welldeveloped leaf, lowermost one with sheath 10–13 cm long, petiole absent or 0.3–0.5 cm long, pulvinus 0.3– 0.4 cm long, blade 18–33 × 8–10 cm, subsequent node with a bladeless sheath, first internode 2.7–6.8 cm long, peduncle 40–70 cm long, hirsute. Main florescence 5.2–9.2 cm long with 7–14 bracts, distichous and ± imbricate at anthesis, first internode 0.6–0.8 cm long, peduncle 0.8–2 cm long; lowermost bract 2.5–2.8 × 1.1–1.2 cm, narrowly elliptic, orangish, subchartaceous, hirsute throughout; first prophyll 15–17 mm long, hirsute throughout or at least on back and at apex. Flowers 5–6 per bract, white; pedicel 1–2 mm long; ovary 1.5–2 mm long, hirtellous apically; sepals 3.5–6.5 × ca 1 mm; corolla tube 18.5–20 mm long, outside glabrous or hirtellous throughout, inside hirtellous in mouth, lobes 4–5 × ca 3 mm; outer staminode 1–3 × 0.5–1 mm, narrowly elliptic, apex entire; stamen 3–3.5 mm long, theca 1–1.5 mm long; callose staminode ca 4.5 × 3–3.5 mm, 0.5–1 mm petaloid apically, with a shelf-shaped callus at ca 3 mm from apex; cucullate staminode ca 3 mm long; style 2.5–3 mm long. Capsule 10–12 × ca 3 mm; seed 10–11 × 2.5–3 mm, narrowly cylindrical; aril ca 1 mm long, tubular without lobes.

Distribution and habitat:—Collected in the western part of the Amazon Basin of Peru and Brazil, in lowland terra firme forests on latosol.

Discussion:— Monotagma aurantispathum is readily recognized by having orange bracts which are ± imbricate throughout anthesis. It is similar to M. smaragdinum and M. flavicomum , both of which have bracts spreading throughout anthesis. It differs from both by having outer staminodes that are smaller (1–3 × 0.5–1 vs. 5.5–7 × 2.5–5.5 mm) and narrowly elliptic (vs. spathulate) with entire apex (vs. bilobed), and shorter capsules (10–12 vs. 16–21 mm).

Paratypes:— BRAZIL. Amazonas: “Camatian” (probably Igarapé Camatiá near São Paolo da Olivença ), January 1949, Fróes 24053 ( IAN) ; Tabatinga , December 1945, Pires & Black 916 ( GH, IAN) . PERU. Loreto: Brillo Nuevo on Río Yaguasyacu, trib. to Río Ampiyacu , April 1977, Plowman et al. 6769 ( GH) ; November 1981, Treacy & Alcorn 625 ( F) ; Pongo de Manseriche, Río Marañón , 1924, Tessman 4631 ( G, possibly mislabeled) .

Figures

FIGURE 4. Monotagma habits. A, M. aurantispathum (Treacy & Alcorn 625); B, M. spathulatum (Schunke 5523); C, M. congestum (Schultes 9951); D, M. nutans (Smith 3706).