Musa arunachalensis A.Joe, Sreejith & M.Sabu, 2013

Sreejith, Puravannoor E., Joe, Alfred & Sabu, Mamiyil, 2013, Musa arunachalensis: a new species of Musa section Rhodochlamys (Musaceae) from Arunachal Pradesh, northeastern India, Phytotaxa 134 (1), pp. 49-54 : 50-53

Musa arunachalensis A.Joe, Sreejith & M.Sabu sp. nov. ( Figure 1 & 2 )

Type:— INDIA. Arunachal Pradesh: West Kameng District, Durga Mandir, way to Bomdilla from Balukpong , 24 March 2012, 774 m, A . Joe & P. E . Sreejith 130835 (holotype CALI!, isotypes CAL!, CALI!) .

Similar to Musa aurantiaca and M. laterita , but differing in having only 1–2 suckers, green pseudostems, almost fully clothed with old brown leaf sheaths; inflorescence erect at first, but bending towards one side later, finally attaining an arch-shape; bracts red-orange with yellow tip adaxially and yellow-orange tip abaxially; fruit bunches lax, arranged at an angle towards the rachis.

Plants slender, suckers 1–2, close to the main shoot, 7–12 cm, vertically arranged. Rhizomes globose, with brown scale bracts and numerous bud like structures. Mature pseudostems 1.4–3 m, 24–40 cm circumference at the base, light green, fully clothed with old brown leaf sheaths except apical region, sap watery. Leaf habit drooping, laminae 80–120 × 39–49 cm, oblong-lanceolate, apices oblique, truncate, with a tendril like appendage when young, adaxially dark green, dull, abaxially medium green with purple coloration, appearance glossy, leaf bases asymmetrical, one side acute and other side rounded, midribs adaxially and abaxially yellow green with purple lines. Petioles 28–39 cm long, glossy, petiole margins straight with erect rim, one side more scarious than the other and with reddish brown blotches at the base, petiole bases winged and clasping the pseudostem. Inflorescences first erect at arising stage, then bending to one side, peduncles 11–17 cm, green, puberulent with short hairs, grooves not prominent. Sterile bracts two, deciduous, 19–26 cm, adaxially light green with dull orange tinge and abaxially green to dull orange. Female buds lanceolate, convolute at tip. Female bracts 17–21 × 8.8–9.9 cm, deeply grooved, adaxially red-orange and yellow tip, dull, yellow-orange abaxially, apices acute, lifting one bract at a time, reflexed towards the rachis before falling. Basal 2–6 hands female. Flowers 3–5 per bract in a single row, 9.2–9.8 cm. Compound tepal 4.8–5 × 1.6–1.7 cm, orange yellow, ribbed at dorsal angles, lobes 5, 0.7–0.8 × 0.4–0.5 cm, dark orange. Free tepal 3.4– 3.6 × 2–2.1 cm, elongate, cream tinged with yellow, yellow at base and apex, slightly corrugated at apex, apex mostly truncate. Staminodes 5, 0.6–1.4 cm, cream with brown apex. Ovary 4.1–5.3 cm, straight, light green, with ovules in 2 rows per locule, style straight, 3.2–3.4 cm, cream, stigma globose, creamy-grey, sticky. Male buds lanceolate, imbricate at apex, rachis arched. Male bracts 15–19 × 7.3–9 cm, deeply grooved, adaxially red-orange with yellow tip, dull, abaxially yellow-orange, glossy, apex acute, lifting one bract at a time, reflexed towards rachis before falling, sometimes bracts revolute and persistent or trapped behind the reflexed bracts, the entire bud degenerating before maturity of the fruits. Male flowers on average 4–6 per bract in single row, 5.8–6.5 cm, falling with the bract, bract scars prominent. Compound tepal 4.9–5.5 × 1.1–1.5 cm, orange yellow, ribbed at dorsal angles, and with 5-toothed dark orange lobes, 0.9–1.1 × 0.4–0.6 cm. Free tepal 4.2–4.5 × 1.6–1.9 cm, translucent cream tinged with yellow, much darker at apex and base, oval shaped, corrugated at apex, apex truncate. Stamens 5, 4.7–5.3 cm, apex exerted, filament cream, 2.4–2.8 cm, anther cream with pink tinge, 2.2–2.7 cm. Pistillodes straight, 0.9–1.2 cm, creamy white, style straight, 4.2–4.4 cm, stigma yellow-orange. Fruit bunch lax, with 2–6 hands and 3–5 fruits per hand, in a single row, fingers arranged perpendicular or pointed towards the rachis, fruits glabrous, straight, pronouncedly ridged, apex lengthily pointed, with floral relicts, immature fruit peel color green with black blotches.

Distribution and habitat:— Musa arunachalensis is distributed in West Kameng District, Arunachal Pradesh, North-East India. This species is growing in the undergrowth and also in forest margins along with M. cheesmanii , M. sikkimensis and M. velutina subsp. markkuana .

Etymology:— The specific epithet is in reference to the name of the state where this species is found.

Flowering and fruiting:— January–May.

Additional specimens examined:— INDIA. Arunachal Pradesh: West Kameng District , Durga Mandir, way to Bomdilla, 30 December 2010, 765 m, A . Joe & Rajesh Kumar 116127 ( CALI), West Kameng District, Durga Mandir , way to Bomdilla, 24 March 2012, 768 m, A . Joe & P. E . Sreejith 130837 ( CALI) . West Bengal: Kalimpong, Kenibreed Plants, 21 April 2013 ,1253 m, M . Sabu 130765 ( CALI) .

Figures

FIGURE 1. Musa arunachalensis. A. habit. B. pseudostem. C. leaf abaxial surface. D. inflorescence at arising stage. E. inflorescence at advanced blooming. F. bract adaxial surface. G. bract abaxial surface. H–K. female flower parts. H. entire flower. I. compound tepal. J. free tepal. K. Pistil with staminodes. L–P. male flower parts. L. entire flower. M. compound tepal. N. free tepal. O. rudiment pistilode with stamens. P. pistilode. Photos by Alfred Joe.

FIGURE 2. Musa arunachalensis. A. inflorescence. B. leaf apex. C. leaf base. D. cross-section of petiole. E. bract (abaxial surface). F–J. female flower parts. F. entire flower. G.compound tepal. H. free tepal. I. cross-section of ovary. J. pistil with staminodes. K–O. male flower parts. K. entire flower. L. compound tepal. M. free tepal. N. rudiment pistilode with Stamens. O. rudiment pistilode. Illustration by Alfred Joe.