วารสารพฤกษศาสตรไทย 9 (1): 31–37. 2560.

THAI JOURNAL OF BOTANY 9 (1): 31–37. 2017.

* Corresponding author: santibio@sut.ac.th Received: 15 October 2016 Accepted: 17 January 2017

ABSTRACT. Porpax capuccinorum Aver., recently described from Laos, is here recorded from two localities in Thailand. As a result, the conservation status is modifi ed from CR to DD.

KEYWORDS: Porpax capuccinorum, Orchidaceae, new record, Thailand

Porpax capuccinorum Aver. (Orchidaceae), a new record from Thailand

SANTI WATTHANA1,2,*, SOMRAN SUDDEE3 & ANDRÉ SCHUITEMAN4

1 School of Biology, Institute of Science, Suranaree University of Technology, 111 University Avenue, Suranaree Subdistrict, Muang, Nakhon Ratchasima 30000, Thailand2 Queen Sirikit Botanic Garden, P.O. Box 7, Mae Rim, Chiang Mai 50180, Thailand3 Forest Herbarium, Department of National Parks, Wildlife and Plant Conservation, Chatuchak, Bangkok 10900, Thailand4 Herbarium, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AE, UK

INTRODUCTION

The genus Porpax Lindl. (1845), in the delimitation adopted by Seidenfaden (1977, 1986) and Pridgeon et al. (2005), comprises 15 species distributed in tropical Asia, from South India and the Himalayan region to Southern China, mainland SE Asia and Borneo. They are small epiphytes or lithophytes with discoid pseudobulbs covered by a tunicate sheath with prominent, persistent veins. The leaves are seasonally deciduous, and the very short infl orescences carry a single, urceolate, usually brownish red fl ower with connate sepals.

As indicated by Seidenfaden (1986) and Schuiteman (2016), two distinct groups can be recognized by using the characters of the

veins of the pseudobulb sheath; these can be either reticulate or radiate. The fl owers can arise in two different periods. The group of species with reticulate veins produces proteranthous infl orescence early in the rainy season, while members of the group with radiating veins produce syn- or hysteranthous infl orescence late in the rainy season or early in the dry season.

Due to their small size, these orchids are easily overlooked in their tropical forest habitats; as a result they are sparsely represented in herbaria (Seidenfaden, 1977). Targeted exploration will almost certainly lead to the discovery of additional species or expand the known distribution area of previously described ones. For example, the new species Porpax thaithongiae Suddee,

Prommanut & Watthana was recently described from Thailand, while P. verrucosa Schuit. was not only a new species but also the fi rst record of the genus from Cambodia (Suddee et al., 2014; Schuiteman, 2016). Still more recently, another new species from Laos has been described, P. capuccinorum Aver. (Averyanov et al., 2016). Thailand seems to be a center of diversity of this genus, with eight species currently recorded, of which four are endemic (Seidenfaden, 1977, 1986; Suddee et al., 2014). In the course of preparing a taxonomic revision of the genus Porpax for the Flora of Thailand by the fi rst author, two specimens could not be identifi ed using the key to the species of Porpax in Thailand (Seidenfaden, 1986). One from Ratchaburi province was wrongly identifi ed as Porpax meirax King & Pantl. (Sitthisajjadham & Tripetch, 2009), after studied type specimen of P. meirax at K. Another specimen col lected in Chiang Mai province is similar to the above-mentioned P. capuccinorum. In spite of minor morphological differences, we decided that these two samples from Thailand should be considered conspecifi c with P. capuccinorum. As the latter was considered to be Critically Endangered, we believe that it is useful to describe the Thai material in detail. Further comparative studies from additional populations and molecular data are required to assess the circumscription of this species. Here, we provide a description, illustrations and color images based on the Thai material.

TAXONOMIC TREATMENT

Porpax capucc inorum Aver. , Turczaninowia 19(3): 45, fi gs. 11 & 12. 2016. Figs. 1–3.

Plant epiphytic, clump-forming, closely appressed to the substrate, to 1.5 cm tall. Pseudobulbs discoid, subglobose to oblong, often bilobed (seemingly in pairs), 5–13 mm long, covered by a tunicate sheath with distinct radiating veins; roots up to 0.5 mm in diameter, densely hairy. Leaves 2 per pseudobulb, base tapering to a petiole 1–2 mm long; blade elliptic, oblong or oblanceolate-oblong, 1–4.5 by 0.3–1 cm, midrib grooved above, prominent underneath, apex acute or retuse (or rarely truncate), the very tip apiculate. Infl orescence short, arising from apex of mature pseudobulb (without or) with fully grown leaves, 1-fl owered; peduncle very short, 1.5–3 mm long; floral bracts conspicuous, scarious, the uppermost larger than the lower, broadly ovate, 3–7 by 2–7.8 mm, margin fi nely erose to entire, midrib distinct, apex acuminate to subcaudate. Flower dark red, 6–14 by 5–9 mm; pedicel and ovary 2–3 mm long, curved, glabrous. Sepals connate, forming a tube 4–6.5 mm long sometimes grooved along the margin of the dorsal sepal, free in apical part, glabrous, gibbous at base; free dorsal sepal lobe triangular or ovate, 3.5–6.5 by 2.8–5 mm, with scattered transparent spots, recurved, with (sub) entire margins, 7–9-nerved, apex obtuse to acute with apiculate at very tip; lateral sepals connate almost to their length, forming an obovate, concave synsepal, 5–9.5

32 Santi Watthana et al.

by 5–9.5 mm with broadly emarginate apex; finely velvety-papillose with scattered transparent spots, 7–9-nerved, each lobe broadly triangular, 1.5–3 by 3–4.5 mm, apex broadly acute, apiculate, recurved. Petals obovate, 3.7–7 by 2.7–6.3 mm, usually longitudinally folded outward, slightly oblique, with entire margins, 7-nerved, apex obtuse. Labellum obovate-oblong, 2.9–3.5 by ca. 1.5 mm in natural position (2–2.5 mm wide when expanded) and concave with upright margin, (obscurely) 3-lobed, margin entire or irregular in the distal part, at base of labellum with a triangular cavity with raised, disk fi nely papillose and wrinkle, labellum apex emarginate. Column 1.5–2 by 0.7–1 mm, column foot distinct, 1.5–2.5 mm long; rostellum orbicular-ovate 0.3–0.4 by 0.3–0.5 mm; anther ovate with a short beak, 0.5–0.7 by 0.5–0.6 mm; pollinia 8, in 2 groups of 4, ovoid laterally compressed, each 0.3–0.4 by 0.25–0.35 mm; stigma suborbicular, 0.4–0.5 by 0.35–0.5 mm. Capsule not seen.

Distribution.— Laos, Thailand.Ecology.— Epiphyte on the lower part

of tree trunks, usually on bark covered by bryophytes and lichens, in limestone forest at 750–850 m elevation.

Phenology.— Flowering in August–October.

Specimens examined.— S. Watthana & W. Buddhawong 4227, Chiang Mai province: Chiang Dao district, Huai Luk, alt. ca. 750 m, 11 October 2014, (QBG!); P. Srisom 40, Ratchaburi province, Khao Krachoom, alt. 850 m, 18 August 2014 (BKF!).

Conservat ion s ta tus .— Porpax capuccinorum is known from three

populations in Thailand and Laos. Since it is easily overlooked, we lack information about its extent of occurrence. Consequently, its conservation status should be assessed as Data Defi cient (DD), following the IUCN Red Listing Criteria (IUCN, 2012).

Notes.— This species belongs to a small group of taxa with radiating (not reticulate) veins of the sheaths that cover the pseudobulbs, and with infl orescences that arise from the apex of mature pseudobulbs towards the end of the growing period, together with the full-grown leaves. The other species in this group are: P. elwesii (Rchb.f.) Rolfe, P. meirax (C.S.P. Parish & Rchb.f.) King & Pantl., and P. verrucosa Schuit. Porpax capuccinorum differs from these three species in that the lateral sepals protrude distinctly beyond the tips of the dorsal sepal and the petals. In addition, P. meirax differs by the ciliate petals; P. elwesii differs by the oblong petals and long-apiculate sepals; P. verrucosa differs by the warty surface of the petals. As here circumscribed, P. capuccinorum is quite variable in the size of the sepals and petals, but considerably less so in the size of the lip.

ACKNOWLEDGEMENTS

The authors are grateful to Mr. Priwan Srisom and Mr. Wins Buddhawong who collected and provided information on the specimens used in this study. Professor Leonid Averyanov is thanked for valuable comments. Part of the fi nancial support for fi eld trips was provided by the Queen Sirikit Botanic Garden (Survey and Study Orchids Project 2014).

Porpax capuccinorum Aver. (Orchidaceae), a new record ݦrom Thailand 33

FIGURE 1. Porpax capuccinorum: A. fl owering plant; B. a fl ower side view; C. longitudinal section of fl ower, with petals removed; D. dorsal sepal; E. petal; F. labellum when expanded; G. labellum in natural position; H. column; I. operculum; J. pollinia. From S. Watthana & W. Buddhawong 4227. Drawn by S. Pimpasalee.

34 Santi Watthana et al.

FIGURE 2. Porpax capuccinorum: A. fl owering Plant; B. a fl ower side view; C. A fl ower front view; D. longitudinal section of fl ower, with petals removed; E. dorsal sepal; F. petal; G. labellum; H. column; I. operculum; J. pollinia. From P. Srisom 40. Drawn by S. Pimpasalee.

Porpax capuccinorum Aver. (Orchidaceae), a new record ݦrom Thailand 35

FIGURE 3. Porpax capuccinorum: A.–B. fl owering plant in natural habitat; C.–D. close up of fl owers. A. and C. from Chiang Mai province, photos by S. Watthana; B. and D. from Ratchaburi province, photos by P. Srisom.

A

B

C D

36 Santi Watthana et al.

REFERENCES

Averyanov, L.V., Nguyen, K.S., Maisak, T.V., Konstantinov, E.L., Nguyen, T.H. & Bounphanmy, S. 2016. New and rare orchids (Orchidaceae) in the fl ora of Cambodia and Laos. Turczaninowia 19(3): 5–58.

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. 2nd edition. Gland and Cambridge.

Lindley, J. 1845. Porpax re ticulata. Edwards’s Botanical Register 3: 62.

Pridgeon, A.M., Cribb, P.J., Chase, M.W. & R a s m u s s e n , F. N . 2 0 0 5 . G e n e r a Orchidacearum. Vol. 4 (Epidendroideae, part 1). Oxford University Press.

Schuiteman, A. 2016. Porpax verrucosa (Orchidaceae), a new species from Cambodia. Kew Bulletin 71: 1–5.

Seidenfaden, G. 1977. Contributions to the orchid fl ora of Thailand VIII. Botanisk Tidsskrif 72(1): 1–14.

. 1986. Orchid Genera in Thailand XIII. Thirty-three epidendroid genera. Opera Botanica 89: 1–214.

Sitthisajjadham, S. & Tripetch, P. 2009. Wild Orchid of Thailand 2. Amarin Printing and Publishing, Bangkok. (in Thai)

Suddee, S., Prommanut, P. & Watthana, S. 2014. Porpax thaithongiae (Orchidaceae) a new species from Thailand. Thai Forest Bulletin (Botany) 42: 100–103.

Porpax capuccinorum Aver. (Orchidaceae), a new record ݦrom Thailand 37