Tridynamia spectabilis

Nomenclature

Accepted name/Authority/Place of publication:

Tridynamia spectabilis (Kurz) Parmar, J. Econ. Taxon. Bot. 18(2): 251. 1994.

Synonyms:

Porana spectabilis Kurz, J. Bot. 11: 136. 1873. — Poranopsis spectabilis (Kurz) Roberty, Candollea 14: 26. 1952. TYPE: Myanmar [Burma]. [? Karen State]: “forests of Martaban, in the Toukyeghat Valley, east of Tongu” [Nakawa Chg], S. Kurz 1083 (lectotype: CAL sheet 314372; isolectotypes: CAL sheet 314371, K).

Porana speciosa Benth. in Benth. & Hooker f., Gen. pl. 2: 876. 1876, sphalm. “spectabilis” ex Jackson Index Kewensis 2: 606. 1894, based on the same type as Kurz’s epithet.

Description

Habit:

Liana to 6(–10) m long, vegetative parts tawny. Lower stem woody; branches terete, 5–6 mm diam., striate, brownish, sparsely tomentellous to glabrous; stem tips terete, 2–3 mm diam., herbaceous, tomentose. Indumentum yellowish-ochraceous, tomentose; hairs 2-armed, arms erect or appressed.

Leaves:

Leaf petiole 1.6–7 cm long, coarsely wrinkled; blade narrowly to broadly ovate or suborbicular, 7.1–19.5 by 4–18 cm, base emarginate to cordate, apex acute or obtuse, apiculate or mucronulate, stiffly chartaceous or subcoriaceous, adaxially olivaceous and subglabrous, abaxially yellowish-olive, tomentellous.

Inflorescences:

Inflorescence a panicle of racemes, 12.5–59 cm long, nodes with raised scars after flowers fall off; lower bracts foliaceous, petiolate, petiole 0.9–2.4 cm long, blade ovate, 5.2–7.2 by 2.7–4.8 cm, base rounded or cordate, apex acute, rounded, or emarginate; bracts diminishing in size apically, becoming sessile, uppermost subulate to ovate, 4–7 mm long; pedicels flattened-filiform, 8–10 mm; bracteoles ovate to ovate-lanceolate, unequal, ca. 1–1.5 mm long, increasing to 3–4 mm in fruit.

Flowers:

Flowers showy, sweetly fragrant; buds slenderly ellipsoid, 1.6–2.2 cm long, apex acute to obtuse, tomentose. Sepals unequal, outer 3 ovate-oblong, flat or incurved, ca. 3–4 by 1 mm, base broader, margins entire, apex rounded, texture herbaceous, with 1 (or 3) longitudinal ridges, glabrous basally outside, otherwise golden-brown tomentose; inner 2 ovate-lanceolate, clasping corolla tube base, ca. 2–3 by 1 mm, lower margins hyaline, apex attenuate, tomentose outside except on hyaline margins, glabrous inside. Corolla narrowly funnelform, 1.9–2.7(–3.3) by 1.7–2.3(–2.7) cm, white, membranous, glabrous inside; tube gradually flaring, base glabrous, otherwise yellowish tomentose; limb 5-lobed, lobes obtuse to rounded, tomentose outside. Stamens unequal, included; filaments 6–10 mm; anthers ca. 2 mm long; pollen 3-colpate, oblate spheroidal, 18–20 by 22–24 micrometer, surface psilate. Pistil included in corolla throat, 12–13 mm long; disc absent; ovary ovoid, attenuate into style, ca. 1 by 1 mm, dark brown below, yellowish distally, glabrous; ovules 4; style 10–12 mm, appressed pilose on lower half, glabrous above; stigma biglobose, taller than broad, ca. 1 mm diam., grayish-tan.

Pollen:

Pollen 3-colpate, oblate spheroidal, 18–20 by 22–24 micrometer, surface psilate.

Fruits:

Fruiting calyx (immature) clasping utricle basally, flaring above; outer 3 sepals greatly enlarged, narrowly obovate-spathulate, flat, 4.9–5.5 by 1.1–1.5 cm, base medially thickened, keeled, margins entire, apex rounded to obtuse, stiffly chartaceous, greenish to tan, outside slightly reticulate, sparsely tomentellous to subglabrous; inner 2 linear-lanceolate, incurved around the utricle, 15–16 by 3–4 mm, apex long attenuate, thinly chartaceous, pale tan, glabrous inside, sparsely tomentellous outside. Utricle (immature) obovoid, ca. 6 by 5 mm, apically rounded, densely yellowish tomentose.

Seeds:

Seed (immature) obovoid, ca. 5 by 3 mm, dark brown to blackish, glabrous.

Author:

G. Staples

References:

Staples, G.W. 2006. Blumea 51: 403–491.

Biogeography, Ecology and Natural History

Distribution Map:

Distribution:

SE Myanmar (Karen and Mon states), W Thailand (map).

Ecology:

Evergreen forests, mixed deciduous/evergreen forests, hardwood
forests, and moist upper deciduous forests, along streams and on the edges of
clearings. The soil type, when recorded, is exclusively limestone. From 100–550
m elevation.

Phenology:

Months

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flowering specimens

Fruiting specimens

Author:

G. Staples

References:

Staples, G.W. 2006. Blumea 51: 403–491.

Other information

Common names and uses:

Ladaa dong (Central Thai dialect).

General comments:

Tridynamia spectabilis is very similar to, and has often been confused with, T. megalantha. However, the floral morphology of T. spectabilis is quite distinct: the corolla is narrowly funnelform corolla, the tube widening gradually from the base upwards, the limb flaring out from it more or less abruptly; the flowers are typically smaller than those of T. megalantha. Furthermore, the staminal filaments are flattened and fused to the corolla tube below, lacking a ‘collar’ at the point where the free portion of the filament departs from the corolla tube, and the outer three fruiting sepals are narrowly obovate to spathulate. Plants of T. spectabilis have a golden-brown or yellowish indumentum, the inflorescence is a panicle composed of racemes, and the three outer fruiting sepals are smooth or only slightly reticulate on the abaxial surface. While subtle, these characters amply distinguish the two species. As defined here, T. spectabilis has a restricted distribution in Myanmar and western Thailand. Plants passing under that name from other parts of Asia are actually T. megalantha.

Authorship for webpage

Editor:

George Staples, Esmond Er

Contributors:

Classification:

Tridynamia spectabilis

Add new comment

form.antibot { display: none !important; } You must have JavaScript enabled to use this form.

Search form

You are here