Thismia annamensis and Thismia tentaculata, Two New Species of Thismiaceae from Central Vietnam
The Herbarium of University of Aarhus, Universitetsparken, Building 137, DK-8000, Aarhus C, Denmark. E mail: firstname.lastname@example.org
Two new species of the genus Thismia Griff. (Thismiaceae), T. annamensis (Sect. Euthismia Schlechter, Subsect. Odoardoa Schlechter) and T. tentaculata (Sect. Euthismia Schlechter, Subsect. Brunonithismia Jonk.) are described and illustrated. Both were discovered recently in lowland areas of central Vietnam and represent important additions to the flora of this country.
Keywords:Thismia annamensis, Thismia tentaculata, New species, Vietnam
The genus Thismia Griff. (Thismiaceae) includes about 30 species distributed mainly in the tropical zone of Asia and America with a few species in subtropical and temperate areas of North America, Japan, China (Taiwan), New Zealand and Tasmania (Ridley, 1924; Jonker, 1948; Yang et al., 2002; Tsukaya & Okada, 2005). The highest species diversity of the genus is found in Southeast Asia including the Malay Peninsula, Sumatra, Java and Kalimantan. Only two species of the genus (Thismia javanica J. J. Smith and T. mirabilis K. Larsen) have previously been reported from the Indochinese Peninsula (Larsen, 1965; Pham-Hoang Ho, 2000). Two additional species discovered recently during field explorations of last years in central Vietnam are described below as new for science. Both species are rare plants known, up to now, only from type localities in central Vietnam. Noteworthy, that all species of Thismia are easily overlooked in botanical explorations due to their dwarf habit and ephemeral character of flowers. It may be reasonable to expect, for both discovered species, a wider distribution in Indochina and existence of further undescribed species of the genus in this area.
Newly discovered taxa
Thismia annamensis K. Larsen et Aver., sp. nov. Figs 1, 2
T. racemosae Ridley affinis, a qua differt caule simplice, pedicellis longiorbus, floribus duplo majoribus, tubo perianthii pyriforme, lobis sepalorum late rhombeis, lobis petalorum anguste rhombeis, lobis stigmatis angustis, ligulatis, ad apicem bidentatis.
Type: VIETNAM, Dak Nong Prov., Dak Glong Distr., Dak Plao Municipality, the territory of Ta Dung Nature Reserve, steep hill slopes at elevation 700-750 m., around point 11º 51'47" N 107º56'59" E, 4 November 2005. L. Averyanov, T. V. Thao, N. T. Vinh, HLF 5510 (Holotype, LE). d-EXSICCATES OF VIETNAMESE FLORA 0036/HLF 5510.
Figure 1. Thismia annamensis K. Larsen et Aver. - a. Flowering plant; b. Flower, view from top; c, d. Longitudinal section of flower; e. Longitudinal section of flower with recurved half of stamen tube; f. Stamen, dorsal surface (turned in flower inside); g. Stamen, ventral surface (turned in flower outside); h, i. Style in ovary (h) and in ripening fruit (i); j. Ripening fruit; k. Apex of ripening fruit; l. Seeds (all drawn from the type by Leonid V. Averyanov).
Figure 2. Thismia annamensis K. Larsen et Aver. - a-c. Flowering plant; d, e. Flowers, view from top; f. Longitudinal section of flower and ovary; g, h. Fruits on different stages of maturation, view from top; i. Fruits, side view; j. Bases of stems and roots (all photographs made from the type by Leonid V. Averyanov).
Figure 3. Localities of Thismia annamensis (●) and T. tentaculata (Δ) in Vietnam.
Small achlorophyllous mycotrophic herb. Roots a few, white to yellowish-gray, fleshy, branching, vermiform, clustering along short horizontal rhizome bearing 1-3 orthotropic stems. Stem light yellowish-brown, simple, glabrous, erect or ascending, 6-9 cm tall with many imbricate bract-like leaves and 1-7 flowers in loose terminal cincinnus. Leaves and floral bracts light yellowish-brown, narrowly triangular to narrowly ovate, acute, adpressed to the stem, 4-12 mm long, 0.8-5 mm wide. Pedicel white, 8-28 mm long, conical; pedicel and ovary longitudinally finely grooved and irregularly dentate along ribs. Flowers actinomorphic, urceolate, of 6 tepals fused to form a basal perianth tube, free apically; below the flowers 2-3 bracts forming loose involucre; perianth tube longitudinal bars connected by many short transverse pyriform, 10-14 mm long, 8-11 mm wide near the bars, at the apex with narrow, prominent, fleshy, apex, chestnut-brown, longitudinally finely grooved olive-brown annulus; free parts of perianth lobes with 12 low rough deep brown ribs, inside with rhomboid; outer lobes broadly rhomboid, 6-8 mm long and broad; inner lobes narrowly rhomboid, 7-9 mm long, 3-4 mm wide; both outer and inner lobes irregularly finely crenulate along margin, terminated at the apex into straight or slightly arcuate filiform process, 6.5-9 mm long; filaments 6, arising from thickened margin of the perianth tube, down curved, connate together into an anther tube 4-5.5 mm long, hanging at an annulus in the perianth throat; individual filaments whitish, hyaline, broad, ribbon-like, at the apex with 5 narrow tooth-like processes (among them 2 obtusely clavate and 3 acuminate), bearing at the middle large anther with two thecae and laterally with two small round glands; on inner side of filament, below anther, with broadly cordate petaloid appendage, wider than stamen, finely denticulate along margin; style black, slender, short, 2-2.5 mm long, cylindrical, persistent, bearing at apex 3 narrow ligulate, bidentate, incurved and converging, glabrous stigma-lobes; ovary deep brown to black, broadly obconical, 4-6 mm long; the 3 placentas inserted parietally in the basal part of the ovary. Fruit deep brown to black, fleshy cupule, crowned by the persistent, fleshy, basal ring of the perianth tube and the style with stigmas; seeds light yellowish-brown, ellipsoid, 0.3-0.35 mm long, with long narrow processes of testa at poles.
Etymology: Species name refers to area of its distribution, which includes mainly lowland and montane regions of central Vietnam (Annam).
Habitat: Secondary open broad-leaved evergreen forest with bamboo and Pinus khesya. Very rare at elevation 700 - 750 m.
Distribution: VIETNAM (Dak Nong Province Dak Glong District). Fig. 3
Note: Thismia annamensis may be compared solely with T. racemosa Ridley once collected in Malacca Peninsula (near Pahang). According to the treatment by F. P. Jonker (1948), new species belongs to Sect. Euthismia Schlechter, Subsect. Odoardoa Schlechter. It differs in simple stems, long pedicels, twice larger flowers and in unequal sepal and petal lobes. A lone small colony of this very rare plant was found in shady humid wet place along forest trail. Hard persistent attempts to find more specimens were fruitless.
Thismia tentaculata K. Larsen et Aver., sp. nov. Figs 4, 5
T. javanicae J. J. Smith et T. arachniti Ridley affinis, a qua differt, tubo perianthii laete albo, intra irregulariter manicato-ruguloso sine transtris transversalibus, apicibus filamentorum bidentatis, glabris, lobis stigmatis ovatis, ad apicem retusis.
Figure 4. Thismia tentaculata K. Larsen et Aver. - a, b. Flowering plant; c, d. Flower, side view and view from top; e, f. Longitudinal section of flower and ovary; g. Base of stem and roots; h. Fruiting plant; i. Ripening fruit, view from top (all photographs made from the type by Leonid V. Averyanov).
Figure 5. Thismia tentaculata K. Larsen et Aver. - a. Flowering plant; b. Flower, view from the top; c, d. Longitudinal section of the flower; e. Longitudinal section of the flower with recurved half of stamen tube; f. Ovary; g. Longitudinal section of ovary; h. Ripening fruit; i. Seeds (all drawn from the type by Leonid V. Averyanov).
Type: VIETNAM, Quang Tri Prov., Da Krong Distr., Huc Nghi Municipality, in vicinities of La To village around point 16º29'16" N 107º00'32" E at elevation about 414 m., 26 March 2006, L. Averyanov, P.V.The et al., HLF 6251 (Holotype, LE). d-EXSICCATES OF VIETNAMESE FLORA 0058/HLF 6251.
Small achlorophyllous mycotrophic herb. Roots a few, light brown, fleshy, vermiform, clustering at the base of stem. Stem white, simple, glabrous, erect or ascending, 2-7 cm tall with a few distant bract-like leaves and 1-3 terminal flowers. Leaves and floral bracts white, narrowly triangular, acute, adpressed to the stem, 2-8 mm long, 0.5-2 mm wide. Ovary and pedicel white, 6-8 mm long, conical, longitudinally finely grooved and irregularly dentate along ribs. Flowers actinomorphic, urceolate, of 6 tepals fused to form a basal perianth tube, free apically; perianth tube broadly conical to obovate, 8-12 mm long, 5-7 mm wide near the apex, pure white, longitudinally finely grooved with 12 low rough ribs, inside with finely irregular manicate-rugulose surface without 2.4 mm long, light yellowish with broadly obtuse or transverse bars, at the apex with broad, prominent, rounded apex; free parts of inner perianth lobes fleshy, brightly yellow annulus; free parts of outer triangular with broad light yellowish base 2.5-3 mm perianth lobes of nearly isosceles triangle form, 1.8-wide, tapering at apex into long, red, filiform, tentacle-like 14-16 mm long process with articulation near the base; filaments 6, arising from thickened margin of the perianth tube, down curved, connate together into an anther tube 4.5-5 mm long, hanging at an annulus in the perianth throat; individual filaments white, yellow at the base, broad, ribbon-like at the apex with two distinct teeth without papillae, bearing at the middle large anther with two thecae and laterally with two round glands; on inner side of filament, below anther, with broadly cordate petaloid appendage, wider than stamen, finely crenulate along margin; style white, thick, short, 1.2-1.6 mm long, cylindrical, persistent, bearing at apex 3 simple, hardly notched, finely papillose, ovate stigma-lobes; ovary white, obconical or obovoid; the 3 placentas inserted parietally in the basal part of the ovary. Fruit white to light brownish, fleshy cupule, crowned by the persistent, fleshy, basal ring of the perianth tube and the style with stigmas; seeds ellipsoid, 0.2-0.3 mm long, with short narrow processes of testa at poles.
Etymology: Plant name reflects the funny resemblance of inner perianth segment processes to tentacles of boiled shrimp.
Habitat: Primary broad-leaved evergreen lowland forest on montane hills composed with shale. Very rare, at elevation 400-500m.
Distribution: VIETNAM (Quang Tri Province, Da Krong District). Fig. 3
Note: According to the treatment of F. P. Jonker (1948) Thismia tentaculata belongs to Sect. Euthismia Schlechter, Subsect. Brunonithismia Jonk. This new species is most similar to Thismia javanica J. J. Smith distributed in Java and Sumatra and T. arachnithes Ridley in Malacca Peninsula. From these closely related species, T. tentaculata differs in bidentate filaments without hairs at apex, finely irregular manicate-rugulose inner surface of perianth tube without transverse bars and in pure white perianth tube. Most probably, a lone record of the genus Thismia from Vietnam reported under the name T. javanica (Pham-Hoang Ho, 2000) belongs to this new species. Only two specimens were found growing on a shady humid slope of small forest stream. Many days' attempts to find more specimens gave no results.
Field and laboratory studies, results of which are presented in this paper, were made according to the investigation program of Vietnamese Botanical Conservation Program supported from Henry Luce Foundation (U.S.A.). We are indebted to Dr Benjamin Ulgaard for latinizing the diagnoses.
Jonker, F. P. 1948.Burmanniaceae. In: Flora Malesiana Ser.1. Vol. 4:13 - 26. Batavia. Noordhoff-Kolff N.V. Larsen, K. 1965.Studies in the Flora of Thailand 27. Thismiaceae. Dansk Bot. Ark. 23: 169-174. Pham-Hoang Ho 2000. In Illustrated Flora of Vietnam. Vol. 3: 1020. Ho Chi Minh. Nha Xuat Ban Tre. Ridley, H. N. 1924. Thismia. Flora of Malay Peninsula. Vol. 4:307-308. L. Reeve & Co. London. Tsukaya, H. & Okada 2005. Thismia mullerensis (Burmanniaceae), a new species from Muller Range, central Kalimantan. Acta Phytotax. Geobot. 56: 129-133. Yang, S.-Z., Saunders, R. M. K. & C.-J. Hsu 2002. Thismia taiwanensis sp. nov. (Burmanniaceae tribe Thismieae): first record of the tribe in China. Syst. Bot. 27:485-488.
(1) Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov str. 2 Saint Petersburg 197376, Russia. E-mail: email@example.com
Received: 26.6.2006 Revised and accepted: 20.9.2006
E.K. JANAKI AMMAL NATIONAL AWARD ON TAXONOMY 2007
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