Tephrosia fusca Wight & Arnott (1834: 210)

Krishnaraj, Moothedathu Venugopalan Nair, Mohanan, Narayanan Nair & Davis, Thomson, 2013, Rediscovery of Robert Wight’s Tephrosia fusca (Fabaceae: Papilionoideae) from India, Phytotaxa 81 (2), pp. 55-60 : 56-57

Tephrosia fusca Wight & Arnott (1834: 210)

Type:— INDIA. Tamil Nadu: Dindygul high hills, s.d., Wight Cat. no. 885 (lectotype E! bar code no. 00174454, isolectotype E! bar code no. 00174455, hic designatus) .

Shrubs, 2–2.5m high; stem softly ferruginous to wooly hairy throughout, bark coarsely fissured. Leaves 10–14 cm long (including petiole), subcoriaceous; stipule ca. 7 × 3 mm, blackish, appressed pubescent outside, glabrous inside, densely velutinous on margins, ovate, long acuminate at apex, acumen folded back, early caducous. Petiole ca. 1 cm long; petiolule 2–2.5 mm long, terete; basal leaflets ca. 1.8 × 1 cm long; middle leaflets ca. 3.7 × 1.6 cm long; terminal leaflets larger or nearly equal to middle leaflets, ca. 4 × 2.2 cm long; all leaflets elliptic-oblong, 9–17 in numbers, imparipinnate, subcoriaceous, abruptly acuminate, obtuse at apex, glabrescent above, appressed silvery to grey pubescent below; lateral nerves 10–15 pairs, prominent below, faint above. Inflorescence axillary or terminal raceme, many flowered, 6–12 cm long; peduncle. ca. 3 cm long; pedicel ca. 1.2 cm long; bracts elliptic, lanceolate, whitish pubescent, ca. 1 × 0.2 cm. Calyx tube ca. 4 mm long, appressed velutinous; upper 2 lobes ca. 4 × 3 mm, ovate-oblong, truncate or round at apex; lower 3 lobes oblong, ca. 3 × 2.5 mm, obtuse at apex. Standard petal ca. 2.7 × 2.6 cm, orbicular, densely ferruginous outside, glabrous inside, purple; claw ca. 1.5 mm long; wing petals oblong-obovate, ca. 1.9 × 0.5 cm; claw ca. 2 mm long; keel petals ca. 1.5 × 0.5–0.8 cm. Staminal sheath ca. 1.4 cm long. Ovary ca. 1.6 × 0.2 cm, densely appressed wooly; style ca. 1.1 cm long; stigma obliquely truncate or pointed, laterally pubescent. Infructescence 12–22 cm long. Pods beaked with stylar remains, later woody, ca. 9 × 0.8 cm long, turgid opposite to seeds, flat between seeds, sparsely appressed golden pubescent, turns to ferruginous pubescent at maturity. Seeds 6–7, ca. 0.7 × 0.5 cm, elliptic, brownish-black, smooth; hilum submedian, ca. 2.25 mm long, with a white rim aril.

Flowering and fruiting:—October–June.

Status:—Endemic to Southern Western Ghats, India. A detailed ecological assesment is essential throughout south India to propose any IUCN categories.

Habitat, ecology, distribution and relationships:—In Kerala this taxon is populated in the rain shadow regions of Idukki district, (10° 14 ' 56. 2'' N, 77 ° 10 ' 25.3 '' E) therefore shows some variations in morphology when compared with type specimen, collected from Dindygul high hills of Tamil Nadu, especially in leaflet number and nature of indumentum. The size and number of leaflets in upper branches that subtends the inflorescence are comparatively lower than other branches. Nine to 13 leaflets are observed from the upper part and maximum of 17 leaflets from lower branches. The indumentum in upper branches is dull-grey in color and gradually changes to white during maturation. This character is common in all parts of the plant. The upper surface of the leaflets is pubescent or glabrous and the stem bark is coarsely fissured. Brummitt (1981) divided the genus Tephrosia Persoon (1807: 328) in to two subgenera, based on the nature of pubescence in style and stigma. However here we followed the observations of Bosman & Haas (1983) because of the fact that it is impossible to correlate the pubescence of the style with any other characters, except that the barbistyled species tend to possess larger flowers. So at present it is better to abstain from formal infrageneric subdivision awaiting a worldwide monograph.

Very few individuals are surviving in Kovilkadavu at Marayoor and Kanthalloor and facing great threat due to human interventions. We cannot rule out the probability of finding this taxon in Tamil Nadu, especially Dindygul high hills and adjoining regions. The taxon is allied to Tephrosia candida Candolle (1825: 249) however differs from the later in having abruptly obtuse leaflets, calyx teeth densely appressed velutinous, pods with ferruginous indumentum and elliptic seeds.

Specimens examined:— INDIA. Kerala: Idukki district , 3 January 2008, Way to Chinnar Wild Life Sanctuary, M. V. Krishnaraj 61976 ( TBGT, CAL) ; Idukki district , 29 June 2011, Kovilkadavu, Marayoor, M. V. Krishnaraj & Thomson Davis 66328 ( TBGT) ; Kanthalloor , 23 October 1986, B. Gurudev Singh & K. R. Sasidharan 12652 ( FRC) .

Note:—According to Noltie (2005:132), the Wight Catalogue numbers (WC) are not actually the collection numbers, but species numbers given by Robert Wight. So the Prodromus specimens at E and K, named after Wight and Arnott should be considered as “original materials” or syntypes, if they are annotated by Wight alone or jointly with Arnott and should be extremely cautious while using the word “ holotype ”, a concept that only evolved 100 years after Wight and Arnott (Noltie, Pers. Comm.). But in some rare cases they actually represent holotype or isotype ( Krishnaraj & Mohanan 2012). There are two sheets of Tephrosia fusca available at Edinburgh herbarium (E), barcoded as E00174454 and E00174455. E00174454 is with Herb.Wight Prop. label, Wight Cat. no: 885 and Wall. List no. 5648, collected from Dindygul hills, belongs to Arnott (GL). E00174455 is with Herb. Wight Prop. label (as separate on lower right hand corner), Wight Cat. no: 885, without Wall. List no. 5648, annotated as Tephrosia argentea?, Dindygul hills, from Wight, Negapatam (=Nagapattinam), belongs to Graham. Noltie (2005: 330) considered E00174454 with HWP label, WC 885 and W. L. n. 5648 as holotype (typographical error, Noltie, (Pers. comm.)) [however annotated as syntype in sheet] and E00174455 as duplicate, therefore cited as isosyntype. Since both are syntypes, Arnott one would be the best choice for lectotype since Graham specimen is clearly a supplicated of the one in Arnott’s herbarium. So we selected E00174454 as the lectotype and E00174455 as an isolectotype as per the

article 9.10 of ICBN (Mc Neill et al., 2006).