Argyreia paivae A.R.Simões & P.Silveira, 2011

Simões, A. R., Silva, H. & Silveira, P., 2011, The Convolvulaceae of Timor with special reference to East Timor, Blumea 56 (1), pp. 49-72 : 50-52

1. Argyreia paivae A.R.Simões & P.Silveira , sp. nov. — Fig. 1 , 2 ; Map 1

Ab Argyreia walshae Ooststr. foliis multo longioribus anguste ovatus (nec late ovatis vel ovatis) et subtus pilis brevibus adpressis rectis (nec crispatis) instructis differt. — Typus: Friedberg 257a (holo LISC), East Timor, Abis, 1.vi.1966 .

Etymology. The name Argyreia paivae is a tribute to Jorge Paiva, who has dedicated his life to the study of tropical flora and who gave a fundamental contribution to this project.

Woody twiner. Stems with milky sap, sparsely pilose with short, appressed whitish hairs when young, later glabrescent and lenticellate. Leaves narrowly ovate, two or more times as long as wide, 6.5–12 cm long, 2 –5 cm broad, rounded at the base, attenuate to acuminate at the apex, glabrous or nearly so above, sparsely to rather densely pilose beneath with short, appressed, straight hairs; midrib and 10 –13 pairs of lateral nerves rather prominent beneath; petiole 2 –5 cm long, appressed-pilose. Inflorescences axillary; 3–10-flowered compound cymes; peduncles shorter or as long as the petiole, 2 – 5 cm long, densely appressed-pilose. Bracts oblong, 2 – 3 mm long, appressed-pilose outside, glabrous inside, caducous. Pedicels 3 – 6 mm, hairy like the peduncles, thickened towards the apex. Sepals subequal, the outer two ovate, the inner three broadly ovate, 5 – 6 mm long, apices obtuse, outside fulvous tomentose, inside glabrous and brown, three inner ones with a slightly scarious margin. Corolla whitish, tubular to funnel-shaped, c. 2 – 3 cm long, the limb shallowly lobed, midpetaline bands and upper portion of the tube sericeous. Stamens slightly exserted; filaments c. 20 mm long, inserted at c. 5 mm from the base of the corolla tube, hairy at the base; anthers sagitate, c. 3 mm long. Disc annular, c. 0.5 mm high. Ovary, 2-celled, glabrous; style glabrous, exserted, 20–25 mm long, stigma globose. Fruit unknown.

Distribution — Timor.

Habitat & Ecology — Thick liana, growing over shrubs, collected at 700 m.

Uses — The bark can be boiled and the resulting water is drunk for treating gonorrhoea.

Vernacular name — Mau halé (Timor: unknown dialect).

Other specimens examined. INDONESIA, West Timor, Nikiniki, 700 m,

1.iv.1974, Kooy 905 ( L!); Supul, c. 750 m , 25.iii.1969, Kooy 706 ( L!) .

Notes — We examined specimens of Argyreia from Timor and three of them stood out because they did not appear to match any of the species of Argyreia included in Flora Malesiana (Van Ooststroom & Hoogland 1953). After careful study, extensive comparison with the descriptions of species from other territories and comparison with herbarium material (especially from BM, K and L), it was found necessary to describe A. paivae as a new species.

Specimens of A. paiva e share some characteristics with each of the other two Timorese endemic species: A. reinwardtiana and A. walshae . Like A. reinwardtiana this new species has the lower leaf surfaces sparsely to rather densely pilose with short, appressed, straight hairs, while in A. walshae the lower surface is densely pubescent to tomentose with short curled hairs. The inner and outer sepals are subequal and thus similar to those of A. walshae . In A. reinwardtiana , the outer sepals are distinctly larger than the inner ones, with peculiar undulate margins. The indumentum of the sepals is also like that of A. walshae , in that it is entirely densely sericeous outside. In A. reinwardtiana , the sepals are distinctly less sericeous towards the apex. A distinctive feature of A. paivae are the narrowly ovate leaves that are at least twice as long as they are wide. The other two Timor endemics have broadly ovate to ovate leaves, the length of which is less than two times the width. Given the distinctive leaf shape of A. paivae , the possibility that it is a hybrid between the two other Timorese species is unlikely.

In the absence of fruit, and in order to confirm that these specimens should indeed be included in the genus Argyreia , we studied the pollen morphology of the three endemic Timor Argyreia ( Fig. 2 ).

The pollen of all three species is very similar, apolar, with radial symmetry, circular in optical section, pantoporate. In detail, they are characterised in the following way: diameter 83–100 µm; pori operculate, diameter of opercula 6 – 8 µm; opercula microreticulate-cristate; exine c. 16 µm thick under the spines, c. 9 µm between the spines; tectum echinate-microreticulate-cristate; spines 6.8 –9.4 µm long (excluding the dilated exine bases), cylindrical, obtuse, psilate, with subglobose, microreticulatecristate bases.

Considering that the fruit of A. reinwardtiana is known (Van Ooststroom & Hoogland 1953) and that the pollen morphology is very similar in all three species, we can confirm that the complex belongs to Argyreia .

Figures

Map 1 Distribution of Argyreia paivae A.R.Simões & P.Silveira (5), A. rein­ wardtiana (Blume) Miq. ($) and A. walshae Ooststr. (:).

Fig. 1 Argyreia paivae A.R.Simões & P.Silveira. a. Node with inflorescence and leaf; b. corolla section, view from inside; c. corolla section, view from outside; d. ovary and disk; e. sepals, view from outside; two on the left inner ones, three on the right outer ones; f. sepals, view from inside; left hand one of the outer sepals, right hand one of the inner sepals (based on Friedberg 257a, LISC, complemented with information from Kooy 706 and Kooy 905, both L).

Fig. 2 SEM images showing detail of indumentum of abaxial surface of the leaf (left) and pollen morphology (right) of all three species of Argyreia from Timor. a, b. Argyreia paivae A.R.Simões & P.Silveira; c, d. Argyreia reinwardtiana (Blume) Miq.; e, f. Argyreia walshae Ooststr.