Indigofera smitinandii S. Mattapha & P. Chantaranothai, 2013

Mattapha, Sawai & Chantaranothai, Pranom, 2013, Two new species of Indigofera (Leguminosae-Papilionoideae) from Thailand, Phytotaxa 129 (1), pp. 47-52 : 47-50

Indigofera smitinandii S. Mattapha & P. Chantaranothai , sp.nov. ( Fig. 1 ).

Indigofera smitinandii can be distinguished from other Thai Indigofera species by symmetric T-shaped hairs, unifoliolate leaves and ciliate to fimbriate wing petals.

Type:— THAILAND. Chaiyaphum, Phu Khieo Wildlife Sanctuary , 16 º 09' 54̎ N , 101 º 39'18̎ E, 20 July 1973, T . Smitinand 11861 (holotype BKF!, isotype BKF!) .

Shrubs c. 1 m high; twigs with adpressed symmetric T-shaped hairs. Leaves unifoliolate, spirally arranged; stipules triangular, 0.5–1 mm long, hairy outside, glabrous inside, caducous; petioles 5–7 mm long, hairy; stipels lanceolate, 2 mm long, caducous; petiolules 2 mm long, hairy; lamina elliptic, 7–9 × 3.5–5 cm, apex acute with mucro 1 mm long, base cuneate to rounded, margin entire, coriaceous; upper surface glabrous, lower surface with the most adpressed symmetric T-shaped hairs; secondary veins 10–15-paired, anastomosing. Racemes 6–10 cm long, axillary, many-flowered; peduncles 1–2 cm long; rachis 5–8 cm long. Flowers 6–7 mm long, pale violet; bracts 1 × 0.5 mm, apex acute, margin ciliate; pedicels 1.5–2 mm long, densely hairy. Calyx cup-shaped, 1 mm long; teeth 0.5 × 1 mm, slightly unequal, densely hairy outside, glabrous inside. Corolla pale violet; standard orbicular, 5–6 × 4–5 mm, apex rounded with minute mucro, margin ciliate, densely hairy on the back, glabrous inside; wings oblong, c. 2 x 1 mm, margin ciliate to fimbriate, glabrous outside and inside; keel as long as standard, margin ciliate, hairy outside along margins, glabrous inside; lateral pocket c. 0.5 mm long, glabrous. Stamens diadelphous (9+1); staminal tube 5–6 mm long, glabrous; filaments 0.5–1 mm long; anthers 1 × 0.5 mm with apiculate, dark brown dots along connective on dorsal side, glabrous. Ovary c. 3 mm long, linear, silvery densely hairy, 7–9-ovuled; style c. 2.5 mm long, glabrous. Pods not seen.

Distribution:—Endemic to Thailand (Phu Khieo, Chaiyaphum).

Habitat & Ecology:—Frequently found in open forest, elevation of 1,000 m, only known from the types.

Phenology:—Flowering & fruiting: July to October.

Observations:—The specimens kept at BKF, T. Smitinand 11861, were determined as I. brunoniana Graham in Wallich (1834) which is confined to Myanmar. However, when the specimens were more thoroughly examined, there are several characters which appear to be dissimilar to that species and other closely related species. Therefore, a Thai unifoliolate leaf Indigofera was fully described here as a new species, and named I. smitinandii . The new species is allied to I. brunoniana in unifoliolate leaves but differs by elliptic lamina and glabrous on the upper surface of leaflets, and also differs from I. maymyoensis Sanjappa (1985: 227) , by shorter petioles and inflorescences, smaller leaflets, and the lower surface of leaflets with the most symmetric T-shaped hairs. The species also resembles to I. caloneura Kurz (1873: 229) in appearance. In contrast, I. caloneura has the most of densely non-symmetric T-shaped hairs on the lower surface of leaflets. The differences in characters of the new species and its relatives are shown in Table 1.

Petiole 7–15 mm long 10–17 mm long 15–30 mm long 5–7 mm long

Number of leaflets (1–)3 1 1 1

Shape of leaflets ovate, elliptic to ovate to broadly ovate ovate to elliptic elliptic

oblong

Size of leaflets 7–16 × 3.5–9 cm 11–14(–25) × (5–)8–13 10–15 × 6–11 cm 7–9 × 3.5–4 cm

cm

Upper surface of leaflets the most symmetric glabrous glabrous glabrous

hairs

Lower surface of leaflets the most symmetric the most non- the most non- the most symmetric hairs symmetric hairs symmetric hairs hairs

Secondary veins 12–13 pairs 19–25 pairs 16–20 pairs 10–15 pairs

Inflorescence 6–29 cm long (8–) 15–20 cm long 10–20 cm long 6–10 cm long

Flower 8–10 mm long, 8–10 mm long, creamy 9–10 mm long, not 5–6 mm long, pale creamy white white known violet

Ovary glabrescent densely hairy densely hairy densely hairy

Pod 3–4.5 cm long 4–5 cm long 3–4 cm long not seen

Distribution endemic to Myanmar Myanmar, Laos, endemic to Myanmar endemic to Vietnam, Thailand Thailand

Etymology:—The specific epithet is greatly honoured to the late Prof. Tem Smitinand, a well-known Thai botanist who collected the specimens.

Figures

FIGURE 1. Indigofera smitinandii. A: leaves and inflorescences, A1: lower surface of a leaflet, A2: two times magnification of A1 showing symmetric hairs; B: a young floral bud; C: standard in dorsal & ventral views, respectively; D: wings; E: keel; F: stamens without a vexillary stamen; G: anthers in ventral and dorsal views, respectively. From T. Smitinand 11861, drawn by M. Norsaengsri.