Monotagma congestum Hagberg & R.Erikss., 2011

Hagberg, Mats & Eriksson, Roger, 2011, New names in Monotagma (Marantaceae), Phytotaxa 20 (1), pp. 1-25 : 22

16. Monotagma congestum Hagberg & R.Erikss. , sp. nov. ( Fig. 4C )

Surculis aereis indeterminatis M. rudanii et M. ulei similis , sed ab eis differt inflorescentia congesta ovoidea.

Type:— BRAZIL. Amazonas : Upper Rio Negro , Rio Dimití, on side of Cerro Dimití, 12–19 May 1948, Schultes & López 9957 (holotype IAN, isotypes UBC, US).

Herb. Basal parts unknown. Aerial shoots with 7–10 nodes, not organized as a synflorescence, main shoot indeterminate, without a terminal florescence, second and subsequent internodes short, <0.3 cm long, each node with a well-developed leaf, florescences and/or leafy shoots arising from axils of main shoot leaves. Leaf at lowermost node with sheath 14–16 cm, papyraceous to chartaceous, puberulent to ± glabrous, auriculate; petiole 0.6–1.2 cm long, terete, appressed-puberulent throughout; pulvinus 0.6–1.6 cm long, ± terete, appressed-puberulent throughout, without annulus; blade ovate, chartaceous when dry, base obtuse to truncate, apex caudate, centric, 25–28 × ca 10 cm, length from base to broadest part ca 8 cm, adaxial surface not papillose, hirtellous throughout, abaxial surface not papillose, glabrous. Florescences in axillary clusters forming a dense ± ovoid head with 17–38 florescences; lowermost florescence 3.5–6 cm long with 9–16 unilaterally arranged bracts, first internode 0.3–0.4 cm long, peduncle 0.4–0.5 cm long; lowermost bract 1.6– 1.7 × 0.5–0.6 cm, greenish, chartaceous, hirtellous throughout; first prophyll 9–11 mm long, hirtellous throughout. Flowers 6–8 per bract, white; pedicel 0.5–1 mm long; ovary 1–1.5 mm long, hirtellous apically; sepals 4–5 × 1–1.5 mm; corolla tube 10–13 × ca 0.5 mm, outside ± glabrous, inside hirtellous in mouth, lobes ca 4 × ca 2 mm; outer staminode ca 4 × ca 2 mm, obovate, apex entire; stamen ca 2 mm long, theca ca 1 mm long; callose staminode ca 3.5 × ca 2 mm, fleshy throughout; cucullate staminode ca 2.5 mm long, appendage ca 0.5 mm long; style ca 2 mm long (tripped). Capsule 9.5–10 × 2.5–3 mm; seed ca 8 × ca 2.5 mm; aril ca 2.5 mm long.

Distribution:—Known only from the type locality, probably a premontane forest.

Discussion:— Monotagma congestum is similar to M. rudanii and M. ulei , but is distinguished by a more condensed aerial shoot system with florescences forming a dense ± ovoid head.

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).