The Genus Indigofera L. (Leguminosae) in Thailand
Total Page:16
File Type:pdf, Size:1020Kb
Tropical Natural History 12(2): 207-244, October 2012 2012 by Chulalongkorn University The Genus Indigofera L. (Leguminosae) in Thailand SAWAI MATTAPHA1 AND PRANOM CHANTARANOTHAI2* 1Department of Biology, Faculty of Science, Udon Thani Rajabhat University, Udon Thani 41000, THAILAND 2Applied Taxonomic Research Center, Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, THAILAND * Corresponding author. E-mail: [email protected] Received: 7 December 2011; Accepted: 28 August 2012 ABSTRACT.– An account of the 30 species (32 taxa) of Indigofera L. found in Thailand is presented, with keys, descriptions, cited specimens, a line drawing, distribution and photographs. I. kasinii Boonyamalik is placed in synonymy of I. lacei. I. laxiflora is lectotypified. KEY WORDS: Indigofera, lectotype, synonym, taxonomy, Thailand (1928). In his treatment, he recognized 22 INTRODUCTION species. The aim of this paper is to describe and provide keys for the 30 species (32 Indigofera L. is the largest genus of the taxa) found in Thailand. tribe Indigofereae, family Leguminosae- Papilionoideae. The genus contains around 700 species found in the tropics and MATERIALS AND METHODS subtropics of the Old and New World (Polhill & Raven, 1981). The genus was The revision is based on the study of first described by Linnaeus in 1753 based on herbarium specimens from the following the three species of I. tinctoria, I. hirsuta herbaria: AAU, BCU, BK, BKF, BM, C, and I. glabra. Later, the first one was CMU, E, K, KKU, L, P, PSU, QBG, SING selected as the lectotype of the genus by and TCD (The abbreviations follow Thiers, Fawcett & Rendle (1920). Three revisions 2011) plus the Biology Herbarium at Chiang of the genus have recently been published. Mai University, which is here abbreviated to De Kort & Theijsse (1984) revised the BH-CMU. Field observations were carried genus for the whole of S.E. Asia, Sanjappa out throughout Thailand and ecological data (1985) for Burma (Myanmar) and Thuân et and location were also recorded. al. (1987) for Indo-China. Some species of the economically important Indigofera RESULTS AND DISCUSSION species are I. arrecta, I. suffruticosa and I. tinctoria, especially the last one is widely Note on Morphology used in the traditional manufacture of the Habit ranges from prostrate shrubs to dye indigo. large shrubs or treelets. Indumentum is In connection with a revision of the present in all species, consisting of T-shaped genus for the Flora of Thailand, we found hairs (medifixed hairs or biramous hairs) quite a number of unnamed specimens of with short or long arms throughout both the genus. The only and lastest checklist of vegetative and reproductive parts. Some the genus for Thailand is that of Craib 208 TROPICAL NATURAL HISTORY 12(2), OCTOBER 2012 species, e.g. I. squalida and I. trifoliate, variable in colour, e.g. greenish, pink, have both disc-shaped glandular and T- purplish or reddish, and sometimes the shaped hairs on the lower surface of the colour of each petal varies slightly within a leaflets, while other species have both species. The standard petal is always larger gland-tipped and T-shaped hairs along the than the others, sessile or with a short claw, stem, twigs and on the surfaces of leaflets or and is usually covered by T-shaped hairs on pods, such as I. colutea and I. scabrida, or the back but totally glabrous in e.g. I. theysome have both simple and T-shaped atropurpurea. The wing petals are as long hairs along the twigs, such as I. emmae. as or shorter than keel petals and always The leaves are usually compound with a ciliate margin. The keel petals of (trifoliolate, imparipinnate), sometimes most species have a lateral or a sac-like simple, such as in I. linifolia, I. pocket on its lamina around the middle, nummulariifolia and I. squalida, or are except for I. aralensis. The stamens are unifoliolate as in I. caloneura. Stipules are diadelphous (9+1). The anther has an present and caducous. Stipels are absent in I. apiculate connective in most species but is colutea, I. dusua and I. glabra, whilst in all lacking in I. aralensis. The pods vary in Indigofera species the rachis is grooved shape, being crested or with four ridges in I. above. The arrangement of leaflets is mostly trifoliata and I. trita subsp. subulata var. opposite, subopposite or a very few scabra, and falcate or sickle-shaped in I. alternating in the lower or middle part of the nummulariifolia and I. suffruticosa. The size rachis in several species. However, a few of pods varies considerably in most Thai species are markedly alternate, viz. I. Indigofera. The direction of pods, as fixed hendecaphylla var. hendecaphylla and var. on inflorescences, is mostly drooping or siamensis and I. linnaei. spreading but is upright in I. galegoides. The inflorescence is racemose in the The dehiscence of pods is found in many axils of the leaves and its length varies species but the indehiscence is found in I. considerably. A short raceme with a few galegoides, I. nummulariifolia, I. tinctoria flowers is found in I. glabra and I. linnaei and I. zollingeriana. whereas a long raceme, about 1 to 2 times as long as the subtending leaf, with very dense TAXONOMIC TREATMENT and many flowers is found in I. lacei, I. laxiflora and I. nigrescence. The bract INDIGOFERA subtends a flower in axillary raceme. The bracteole or a bract-like scale attaching to a L., Sp. Pl.: 751. 1753; Benth. & Hook.f., pedicel is absent. The flower is a Gen. Pl. 1: 494. 1865; Baker in Hook.f., Fl. papilionaceous form. The calyx is cup- Brit. Ind. 2: 92. 1876; Gagnep., Fl. Indo- shaped with minute teeth or slightly truncate Chine. 2: 422. 1916; Hutch., Gen. Fl. Pl. 1: lobes. The length of the calyx lobes is as 400. 1964; J.B. Gillett, Pl. Trop. E. Afr., long as or shorther than the calyx tube in Leg. Pap. 1: 212. 1971; Polhill in Polhill & most species but longer than the calyx tube Raven, Adv. Legume Syst.: 289. 1981; de in I. caudata, I. hirsuta, I. linifolia and I. Kort & G. Thijsse, Blumea 30: 89. 1984. trita subsp. subulata var. scabra. The Lectotype: I. tinctoria L., selected by corolla is caducous during anthesis and is Fawcett & Rendl, 1920. MATTAPHA AND CHANTARANOTHAI — INDIGOFERA IN THAILAND 209 Treelet, shrub or prostrate shrub. T- truncate. Corolla: papilionaceous; standard shaped hairs: appressed to spreading with larger than others, sessile or with a short subequally or very unequally long arms, claw; wing petals as long as or shorter than sometimes mixed with disc-shaped keel petals, margin always ciliate; keel glandular hairs or gland-tipped hairs. petals with a lateral pocket or a sac-like Leaves: simple, unifoliolate, trifoliolate to pocket, on its lamina around the middle. imparipinnately compound, alternate or Stamens: diadelphous (9+1), alternately spiral, stipulate; petioles pulvinate; rachis shorter or longer; anthers with an apiculate grooved above. Leaflets: opposite, connective, and tufted hairs at base or apex. subopposite or alternate, the upper most of Ovary: superior with 1-many ovules, leaflets larger than others; midrib grooved glabrous or hairy. Pods: cylindric, globose above and raised below; lateral viens to subglobose, rarely moniliform or ridged, indistinct, somewhat invisible; stipels straight or falcate, dehiscent, rarely usually present, caducous. Inflorescences: indehiscent; endocarp septate between racemose, axillary; bracts very caducous; seeds. Seeds: globose, elliptic or cubic, bracteoles absent. Calyx: cup-shaped with shiny. distinct 5 lobes or minute teeth to slightly KEY TO THE SPECIES 1. Leaves simple or unifoliolate …………………………………………………………….... 2 1. Leaves imparipinnate, with 3 or more leaflets …………………………………………….. 5 2. Leaves simple (stipellae absent) ………….…………..…………………………………… 3 2. Leaves unifoliolate (stipellae present) …...……………………………….… 4. I. caloneura 3. Ovary with 1-2 ovule(s) ………………………...…………………………………………. 4 3. Ovary with 5-6 ovules ………………………………………………………. 24. I. squalida 4. Pods falcate, echinate …………………………………………….... 20. I. nummulariifolia 4. Pods globose or subglobose, not echinate ………………………...…………. 18. I. linifolia 5. Leaves trifoliolate; lower surface of leaflets with disc-shaped glandular hairs …………….. …...……………………………………………………………………..…… 27. I. trifoliata 5. Leaves with more than 3 leaflets; if with 3 leaflets, lower surface of leaflets without disc- shaped glandular hairs …………………..…………………………………………………. 6 6. Leaflets distinctly alternate ………………………………….…………………………….. 7 6. Leaflets opposite, subopposite or rarely a few alternating 3-4 pairs in lower or middle part of rachis ………………………………………………………………………………...….. 8 7. Pods less than 5 mm long .…………………………………………………….. 19. I. linnaei 7. Pods more than 15 mm long …………………………………………. 13. I. hendecaphylla 8. Gland-tipped hairs present ……………………………………………………………….... 9 8. Gland-tipped hairs absent ……………………………………………………………….... 10 9. Standard obovate, 4-4.5 mm long …………………………………………...… 7. I. colutea 9. Standard orbicular, 6-7 mm long …………………………………………… 22. I. scabrida 10. Both surfaces of leaflets with slightly symmetric T-shaped hairs or glabrous …………. 11 10. Either lower or upper surface of leaflets with asymmetric T-shaped hairs ….……….…. 25 11. Racemes much longer, ca. 1 to 2 times as long as the subtending leaf ……………….… 12 11. Racemes slightly longer, as long as or less than the subtending leaf …………………… 13 210 TROPICAL NATURAL HISTORY 12(2), OCTOBER 2012 KEY TO THE SPECIES (Continue) 12. Leaflets 9-19; racemes with lax flowers ………………………………..…. 17. I. laxiflora 12. Leaflets