Monotagma spathulatum Hagberg & R.Erikss., 2011

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

14. Monotagma spathulatum Hagberg & R.Erikss. , sp. nov. ( Fig. 4B )

Monotagmatis dolosi similis sed ab eo differt rhizomate partim epigaeo (vs. hypogaeo), foliis basalibus spirodistichis (vs. distichis vel irregulariter dispositis), lamina elliptica (vs. ovata), et florescentiae primo internodio breviore (0.4–0.7 vs. 0.7–1.1 cm longo).

Type:— PERU. San Martín: Cerro Sinsín, 15 km W of Tocache Nuevo along road to Puerto Pizana , 550–580 m, 17 December 1981, Plowman & Schunke 11470 (holotype F, isotype GB) .

Herb 0.25–1 m tall. Rhizomes usually partly above ground and supported by “stilt” roots, branched to form clusters of 2–5 shoots, each shoot bearing 3–8 spirodistichous basal leaves. Ultimate basal leaf with sheath 12–21 cm long, subchartaceous to chartaceous, puberulent to hirtellous throughout, auriculate; petiole 0.3–17 cm long, laterally flattened, puberulent to rarely hirtellous; pulvinus 0.3–0.6 cm long, terete, puberulent throughout or at least adaxially, without annulus; blade very narrowly elliptic, ± papyraceous when dry, base cuneate, apex caudate, centric, 18–32 × 4–5.4 cm, length from base to broadest part 5–8 cm, adaxial surface ± papillose, puberulent to rarely hirtellous along midrib, major lateral veins and margins, and at apex, very rarely puberulent throughout, abaxial surface not papillose, glabrous or hirtellous to hirsute at apex. Synflorescence 2-nodate with 3–6 florescences, first and sometimes also second node with a well-developed leaf, lowermost one with sheath 3.5–16 long cm long, petiole (0–) 0.2–11 cm long, first internode 2–10.5 cm long, peduncle 5.5–40 cm long, usually hirtellous. Main florescence 4.4–6 cm long with 6–12 ± distichous bracts, first internode 0.4–0.7 cm long, peduncle 1.1–1.8 cm long; lowermost bract 1.8–2.1 × 0.6–0.9 cm, greenish, chartaceous, puberulent or rarely hirtellous throughout; first prophyll 12–14 mm long, hirtellous on back and at apex. Flowers 6–7 per bract, white except for the greenish sepals; pedicel 0–1 mm long; ovary ca 2 mm long, glabrous; sepals 6–9.5 × ca 1 mm; corolla tube 15–18 mm long, outside hirsute towards lobes, inside hirsute except for a glabrous basal portion, lobes 5–5.5 × 1.5–2 mm; outer staminode ca 6.5 × ca 5 mm, spathulate, emarginate or entire apically, probably shed early after pollination, rarely preserved in dried specimens; stamen 4–4.5 mm long, theca 1–1.5 mm long; callose staminode 3.5–4 × 2.5–3 mm, 0.5–1 mm petaloid apically, with a shelf-shaped callus 2–2.5 mm from apex; cucullate staminode ca 3.5 mm long, appendage 1–1.5 mm long; style ca 2 mm long (tripped). Capsule 15–20 × 2.5–3.5 mm; seed 15–19 × 2.5–3.5 mm, narrowly pyramidal; aril 3–4 mm long, tubular without lobes.

Distribution and habitat:— Monotagma spathulatum has a restricted distribution along the middle Huallaga River around Tocache Nuevo in Peru. It occurs in ± primary, lower montane forests, usually on slopes at 500–950 m elevation.

Discussion:— Monotagma spathulatum is most similar to M. dolosum , but differs by having rhizomes partly above ground supported by “stilt” roots (vs. subterraneous), spirodistichous phyllotaxy (vs. distichous to irregular), elliptic leaf blades (vs. ovate), and a shorter first florescence internode (0.4–0.7 vs. 0.7–1.1 cm).

Paratypes:— PERU. San Martín: 12 km W of Tocache Nuevo , March 1979, Gentry et al. 25606 ( MO) ; Palo Blanco, 10 km W of Tocache Nuevo , March 1976, Kennedy & Plowman 3642 ( F, GB, GH) ; December 1981, Plowman et al. 11313 ( F, GB) ; 7.4 km N of Pulcache , December 1981, Plowman & Schunke 11640 ( F, GB) ; E of Caserío Bambamarca, Tocache Nuevo , November 1972, Schunke 5523 ( F, L) ; 3 km along road to Pushurumbo from Palo Blanco , March 1978, Schunke 9959 ( GB, MO) ; Challuayacu, Tocache Nuevo , February 1979, Schunke 10761 ( GB, MO) . CULT. Lyon Arboretum , January 1985, Kennedy 4470 ( GB) ; Lyon Arboretum (orig. from Campanilla, Peru ), February 1986, Nagata 3448 ( GB) .

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).