THREE NEW GESNERIACEAE FROM PALAWAN, PHILIPPINES

* Two new species of Aeschynanthus and one new Henckelia are described and illustrated. Trichosporum grandiﬂorum Elmer (non D. Don) is transferred to Aeschynanthus and renamed A. elmeri

axillary or pseudoterminal, 2-4-flowered. Peduncles (3-)8-20mm, sparsely white hairy, sometimes borne on short spurs. Bracts 1-3mm, oval, white hairy. Bracteoles 1.5-6mm, broadly elliptic, sparsely white hairy. Pedicel green, 14-16mm, slender, abruptly widening at apex, with scattered minute eglandular hairs. Calyx 5-8mm, bowl-shaped with shallow incurving lobes and with abscission layer at base, pale greenish-white flushed reddish in apical half, externally with occasional minute eglandular hairs towards apex. Corolla tubular, arcuate, 5.2-5.7cm, with small asymmetric gibbosity at base then flaring gently to throat, lobes spreading; externally bright scarlet, pale at base, internally cream at base of lobes and in throat and tube, with a red central line on each of the three lower lobes, upper lobes c.9×4mm (central sinus 3mm), lateral and lower lobes c.9×9mm, all rounded triangular and fringed with tiny glandular hairs; externally with sparse 0.3mm red glandular hairs on tube, internally with thickened papillate areas where lobes fuse and with short papillae in throat and nectar-containing tube. This species, with its trailing, flexuous stems and shallowly lobed calyx detaching easily from the pedicel, is a typical member of sect. Aeschynanthus. The seeds lack the podium of 'bubble cells' at the base of the hilar appendage that was at one time thought to be diagnostic for the section (Clarke, 1883;Burtt & Woods, 1975), but some other members of the section, including the Bornean A. tricolor Hook. and the Palawan A. arctocalyx Mendum, also lack bubble cells. The large bright red corollas, cream in throat and tube and with a gibbosity at the base, are usually associated with tubular calyces; the calyx of A. curvicalyx, to which the epithet refers, is very different. The type was grown from seed; wild-collected cuttings of the same plant are cult. RBGE accession no. 19980281.
Again this species is typical for the section, but differs from the large flowered Bornean members with tubular calyces in that it lacks the pronounced gibbosity at the base of the corolla seen in the latter.
Aeschynanthus madulidii is named in honour of Dr Domingo Madulid, head of the Division of Botany, the National Museum, Manila, who has been of much help in facilitating our fieldwork.
The Philippine Trichosporum grandiflorum Elmer, from Mindanao, is similar to A. madulidii but differs in its glabrous slightly flared calyx with larger lobes, a lack of papillae on the floor of the corolla tube and much larger anthers. The transfer of this species to Aeschynanthus requires a replacement name because A. grandiflorus (D. Don) Spreng. exists already as a synonym of A. parasiticus (Roxb.) Wall. The necessary new name is: Aeschynanthus (sect. Aeschynanthus) elmeri Mendum, nom. nov. Syn.: Trichosporum grandiflorum Elmer, Leafl. Philipp. Bot. 7: 2667(1915; non D. Don 1822. Henckelia corrugata Mendum, sp. nov. Fig. 2A-F Upright herb. Stems to 80cm, leafless and woody in lower part, brown hairy in leafy part, sometimes branching near base. Leaves opposite, strongly corrugated, crowded towards apex of stem, to 21.5×4.1cm, linear-lanceolate, apex acute, base rounded, margins irregularly serrate, bright green above and paler with prominent reddish mid-vein below, with brown antrorse hairs along mid-vein above and below, along lateral veins below, and dense at leaf base and on 5mm petiole ( leaves on juvenile plants ovate-lanceolate with petioles to 12mm). Inflorescences axillary in dichasial cymes, flowers sweetly scented. Rhachis 9.5-11cm. Calyx divided to base, lobes 3×0.8mm, linear, pale green, externally with colourless glandular hairs. Corolla 17mm, dorsoventrally compressed, strongly 2-lipped, floor of lower lip and tube deeply ridged and channelled, tube 8mm, two upper lobes reflexed, 6×5mm (central sinus 3mm) rounded, tips of three lower lobes deflexed; lateral lobes 9×5mm, rounded oblong, lower lobe 4×5mm, rounded; corolla externally white with colourless glandular hairs, internally white with pale purple lobes, hairs at base of upper lobes purple, hairs on lower lip to 1.3mm, pale yellow and very papillose, hairs on floor of tube shorter, smooth and purple. Stamens 2, filaments 6mm, white; anthers cohering, ovate, 2.5×1mm, white; pollen white; paired staminodes unequal, c.2mm, third staminode minute. Disc 1.5×2mm, yellow, glabrous. Ovary green with dense colourless glandular hairs and sessile glands. Style 4.5mm, white, hairy at base. leaves to 14cm and inflorescences bearing single 3cm flowers (Merrill, 1925). The Bornean H. crenata (Baker) B. L. Burtt (syn. Didymocarpus multinervius Merr.) appears similar to H. corrugata, another indication of the island's Bornean affinities ( Weber & Burtt, 1997), but the leaves are described as being smooth or slightly bullate (Merrill, 1923a). Henckelia corrugata is known only from the type and was grown from leaf cuttings; the epithet refers to the ribbed leaf surface. The sterile wild-collected specimen, 'Herb to 80cm. Rootstock woody. Leaves in top third only.', is a unicate in PNH.

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Thanks are due to Dr R. R. Mill for the Latin diagnoses, to Mr B. L. Burtt for helpful discussion, and to the horticultural staff at RBGE, especially S. Scott and A. Fowler, for their skill and interest. Thanks are also due to the staff of the Philippine National Herbarium, and to our guides in Palawan.