Exacum courtallense Arnott. A. Habit 1839

Autor: Geethakumary, M. P., Deepu, S., Kissling, J., Pandurangan, A. G.
Rok vydání: 2022
Předmět:
DOI: 10.5281/zenodo.7021603
Popis: Exacum courtallense Arnott (1839: 175). Type:― INDIA. Tamil Nadu: Tirunelveli District, Courtallum hills, August 1835, Wight 1835. 553 (lectotype E [barcode E00001507, image], designated by Klackenberg (1985: 66); isolectotypes E [barcode E00001508, image], NY [barcode NY00297601, image]). Perennial herbs, to 30 cm tall; low, bushy, dichotomously branched from the base (older plants occasionally diffuse). Stem terete at the base, sharply 4-angular at medio-distal portion; young branches 4-lineolate; internodes 4–45 mm long. Leaves opposite, sessile, orbicular (when young) to lanceolate, 10–45 × 7–23 mm, succulent, glabrous, green, base cuneate, stem-clasping, margin scarious, apex acute to obtuse, (1–)3–5 veined, secondary veins diverging from base of the lamina, abaxially prominent. Inflorescence terminal, 5-flowered cyme, rarely solitary from terminal axis; peduncles 15–20 mm long; pedicels 8–15 mm long, slightly enlarging in fruit (10–20 mm), straight. Calyx 5-lobed; tube about half the length of the calyx, campanulate, 3–4 mm long; lobes 6–7 mm long, overlapping at the base in fruit, tapering to a long point at the apex, winged; wings ca. 2 mm broad, rounded or in fruit subcordate at the base, accrescent in fruit with prominent veins. Corolla tube ca. 6 mm long, green; lobes 5, obovate, 11–13 × 6–7 mm, obtuse to acute at apex, long persistent in fruit but eventually deciduous, blue to deep blue. Stamens 5, 8–9 mm long; filaments ca. 3 mm, as long as the anther, attached at the distal portion of the corolla throat; anthers bottle-shaped with a long narrow neck, ca. 6 mm long, base cordate, opening by apical pores that later widen to slits to the base, without papilla. Ovary oblong, ca. 5 mm long; style 10–12 mm long, curved; stigma capitate. Capsule oblong-ovate, ca. 7 × 3 mm, dehiscing septicidally, 2-valved; fruiting pedicel straight; style persistent. Seeds many, irregularly rhomboid, angular, with shallowly sunken sides (Fig. 1). Phenology:—Flowering and fruiting were observed from September to February. Chromosome number:—2n= 68 (Mallikarjuna et al. 1987) Distribution and Habitat:—Occurs in the rocky outcrops, mostly in high altitude grasslands in the southern Western Ghats of Kerala and Tamil Nadu. Specimens examined:— INDIA. Tamil Nadu, Tirunelveli District, Courtallum hills, 1836, Wight 1836.552 (MH). Kerala, Thiruvananthapuram District, Ponmudi, ± 793 m, 7 December 2014, Geethakumary 83197 (TBGT); ibid., 18 October 2015, Geethakumary 84385 (TBGT); ibid., 12 January 2015, Geethakumary 84743 (TBGT); ibid., 7 December 2015, Deepu Sivadas 78878 (TBGT); ibid., 10 January 2016, Geethakumary 84794 (TBGT). Note:—The specimen NY00297601 is likely to be the material studied by Arnott as this material reached NY from Arnott’s collection.
Published as part of Geethakumary, M. P., Deepu, S., Kissling, J. & Pandurangan, A. G., 2022, Revisiting the taxonomy of Exacum courtallense (Gentianaceae) and recognizing E. courtallense var. laxiflorum at the species rank, pp. 185-192 in Phytotaxa 559 (2) on pages 186-187, DOI: 10.11646/phytotaxa.559.2.7, http://zenodo.org/record/7021601
{"references":["Arnott, G. A. W. (1839) Exaci species ex peninsula Indica ac ex insula Ceylano. Annales de Sciences Naturelles; Botanique, Ser. 2, 11: 175 - 176.","Klackenberg, J. (1985) The genus Exacum (Gentianaceae). Opera Botanica 84: 1 - 144.","Mallikarjuna, M. B., Scheriff, A. & Krishnappa, D. G. (1987) Chromosome number reports XCVII (ed. A. Love). Taxon 36: 766 - 767. https: // doi. org / 10.1002 / j. 1996 - 8175.1987. tb 00894. x"]}
Databáze: OpenAIRE
Externí odkaz: