Borneocola Y.Y.Sam, 2016

Sam, Yen Yen, Takano, Atsuko, Ibrahim, Halijah, Zaveska, Eliska & Aziz, Fazimah, 2016, Borneocola (Zingiberaceae), a new genus from Borneo, PhytoKeys 75, pp. 31-55 : 35-38

Borneocola Y.Y.Sam gen. nov.

Diagnosis.

Similar to Scaphochlamys and Myxochlamys . Borneocola has thin, translucent and marcescent floral bracts, absence of coloured streaks on labellum and two dorsal knobs on the stigma versus the coriaceous and persistent floral bracts, coloured streaks on labellum and absence of dorsal knobs on the stigma in Scaphochlamys . The mucilage on the floral bracts and the versatile anther of Myxochlamys are absent in Borneocola .

Type species.

Borneocola reticosus (Ridl.) Y.Y.Sam, comb. nov. Gastrochilus reticosa Ridl., J. Straits Branch Roy. Asiat. Soc. 44: 195 (1905).

Description.

Terrestrial rhizomatous herb, evergreen, rarely exceeding 50 cm in height. Rhizome creeping on the ground, terminal decumbent, rhizome elements short or long; roots fine, extensive, not tuberous. Leafy stem unifoliate, enclosed by a few bladeless sheaths at base, bladeless sheaths linear, papery, glabrous to hairy, light green or light brown, decaying early, leaf sheath glabrous or hairy, base swollen, margin thin and narrow; ligule membranous, inconspicuous, decaying early; petiole channelled in cross section, glabrous, lamina narrowly ovate to elliptic, rarely oblong, asymmetric, margin entire, smooth.

Inflorescence flowering from base to apex; peduncle short, usually hidden within leaf sheath; spike composed of compact rachis and 2-5 (-13) fertile bracts, bracts spirally and closely overlapping (rarely distichous), boat-shaped, 2-keeled, pink, pale brown, pale or light green, thin, translucent, glabrous or hairy, decaying early, marcescent, amplexicaul at the base of the bract, cincinni compact, 2-3 flowers in each cincinnus. First bracteole directly opposite floral bract and enclosing all the flowers and subsequent bracteoles, linear-shaped, 2-keeled, shorter than bracts, rarely same length. Flowers thin, delicate, ephemeral. Calyx tubular, splitting unilaterally on one side, floral tube long slender, usually puberulent externally, inner surface with a groove enveloping the style, corolla lobes 3, triangular ovate, translucent, glabrous, dorsal lobe apex hooded, lateral lobes 2, narrower than dorsal lobe. Staminodes elliptic to narrowly obovate, white, light yellow or green, spreading laterally, lined with translucent veins from base to apex, covered with glandular hairs on adaxial surface. Labellum obovate, flat, bilobed distally, rarely entire, translucent veins spread from base to apical part, pale white, pink, lilac or violet, median band light yellow or greenish yellow, without coloured streaks or patches beside the band, adaxial surface covered with glandular hairs. Stamen bends forward over labellum, usually white and covered with glandular hairs on abaxial surface, filament grooved, short, anther theacae 2, linear, dehiscing along entire length, basal ending with or without short spur, anther crest short, not recurved. Ovary ellipsoid, glabrous or sparsely hairy, unilocular, with basal placentation, less than 10 locules. Stigma small, held at apex of thecae, near oblate, 2 dorsal knobs, ostiole forward facing, ciliate. Epigynous glands 2, filiform, yellow. Fruit a capsule, ellipsoid or ovoid. Seeds not seen.

Etymology.

This new genus is named after the island of Borneo and - cola (Latin) means dweller or inhabitant. This is to recognise the extremely rich and unique biodiversity that is found in Borneo.

Distribution.

Borneo. The genus is currently known to occur only in the northwest and possibly central Borneo. Eight species are recorded from Sarawak, Malaysia and many more are undescribed.

Key to Borneocola species (modified from Ooi and Wong 2014)

1	Adaxial lamina with distinctly raised tessellate venation	6 Borneocola reticosus
-	Adaxial lamina without distinctly raised tessellate venation	2
2	Lamina broadly oblanceolate and elliptic to oblong, lateral veins conspicuously raised on adaxial surface	1 Borneocola argenteus
-	Lamina linear, lanceolate to broadly ovate and elliptic, lateral veins not conspicuously raised on adaxial surface	3
3	Lamina linear to very narrowly lanceolate, <3 cm wide	8 Borneocola stenophyllus
-	Lamina lanceolate, ovate to elliptic,> 3 cm wide	4
4	Leaf sheath plus petiole <10 cm long; lamina apex broadly acute to rounded, base cuneate	4 Borneocola iporii
-	Leaf sheath plus petiole> 10 cm long; lamina apex acute to acuminate, base attenuate, cordate, rounded or truncated	5
5	Lamina lanceolate to ovate, <7 cm wide	6
-	Lamina elliptic to broadly elliptic and ovate,> 7 cm wide	7
6	Basal lamina rounded to truncated; inflorescence stalk 3-9 cm long; labellum pale lilac	5 Borneocola petiolatus
-	Basal lamina attenuate; inflorescence stalk 1-2 cm long; labellum purplish blue	2 Borneocola biru
7	Inflorescence about 3 cm long; labellum pale pink	7 Borneocola salahuddinianus
-	Inflorescence> 7 cm long; labellum white	3 Borneocola calcicola