Camchaya thailandica Bunwong, Chantar. & S.C.Keeley, 2012

Bunwong, Sukhonthip, Chantaranothai, Pranom & Keeley, Sterling C., 2012, A new species of Camchaya (Asteraceae, Vernonieae) from Thailand, PhytoKeys 12, pp. 53-57 : 54-55

Camchaya thailandica Bunwong, Chantar. & S.C.Keeley sp. nov.

Type.

Thailand. Prov. Udon Thani, rare on rocky areas in Phu Phrabat Historical Park. alt. 300 m, 17°43.84'N; 102°29.65'E, 29 September 2007 (flower) S. Bunwong 328 (holotype KKU, isotype US) ( Figures 1 -3 ). Known only from the type collection.

Annual. Inflorescences axillary or terminal, pedunculate. Phyllaries imbricate in 5-6 series, arachnoid-glandular, apices purple. Differs from Camchaya gracilis (Gagnep.) Bunwong & H.Rob. in having ovate acuminate rather than broadly ovate acute phyllaries without margin spines, 10-ribbed rather than 4-5-ribbed achenes, and broadly ovate leaves.

Annual herbs, 50-100 cm tall. Stems erect, rounded, inconspicuously ribbed, scabrous, hairs uniseriate, T-shaped, and glandular. Leaves alternate; petioles to 2 cm long; blades elliptic to oblong, 3-8 by 2-3 cm, chartaceous; bases attenuate, margins serrate, apices acute; both surfaces pubescent, hairs cylindric, T-shaped, and glandular, lateral veins 5-10 pairs. Capitulescences terminal and axillary, corymbose. Capitula pedunculate, involucres broadly campanulate, 5-6 mm diam. Receptacles convex, 2.5-3 mm diam., glabrous. Phyllaries 5-6-seriate, imbricate,light green with purple apices, 7-8 mm long, margins pale, without margin spines, outer surfaces arachnoid-glandular; the outer and the middle ones ovate, apices acuminate; the inner ones lanceolate to oblong, apices acuminate. Florets 50-70; corollas infundibular, purple, pubescent, glands capitate; tubes 6-7 mm long; lobes 2.5-3 mm long. Anthers ca. 2 mm long, bases rounded, apical appendages acute. Styles purple, 6-7 mm long; branches 2-2.5 mm long; sweeping hairs on the outer surfaces reaching below style bifurcation. Achenes obovate, ca. 1.5 mm long, glandular, 10-ribbed, carpopodium absent. Pappus bristles, uniseriate, 1-2 mm long, sometimes absent, deciduous. Pollen echinolophate, 6-porate, without micropuncta.

Distribution.

Endemic to Thailand. Only found in Phu Phrabat Historical Park, Udon Thani province.

Ecology.

Rocky areas of sandstone hills, scattering in dipterocarp forest, flowering from November and December.

Discussion.

Camchaya thailandica is similar to Camchaya gracilis in having ovate phyllaries without spines on the margin, but differs in having 10-ribbed achenes and a broadly ovate leaf shape. Its 6-porate echinolophate pollen is unique to Camchaya ( Bunwong and Chantaranothai 2008) and places it firmly in this genus. Additionally, this species has an inconspicuous carpopodium which is common in Camchaya .

Key to the genus Camchaya

1	Phyllaries broadly ovate without margin spines	2
-	Phyllaries broadly ovate with margin spines	3
2	Achenes 4-5-ribbed	Camchaya gracilis
-	Achenes 10-ribbed	Camchaya thailandica
3	Achenes 5 (6-9)-ribbed	Camchaya pentagona
-	Achenes 10-ribbed	4
4	Phyllaries eglandular, margin spines to 10 mm long	Camchaya spinulifera
-	Phyllaries glandular, margin spines to 5 mm long	5
5	Phyllaries acuminate; achenes 2.5-3 mm long	Camchaya kampotensis
-	Phyllaries aristate or apiculate; achenes 1.5-2 mm long	6
6	Leaves with T-shaped hairs; phyllaries spinose ≤ 1 mm long	Camchaya loloana
-	Leaves without T-shaped hairs; phyllaries spinose ≥ 1 mm long	Camchaya tenuiflora

Figures

Figure 1. Capitulescences, A-B terminal C axillary. Note that phyllaries are in 5 - 6 series and without margin spines.

Figure 3. A-B SEM micrographs of acetolysed pollen show 6 - porate echinolophate pollen. (scale bars = 6 µm).