Scaphochlamys baukensis Y.Y.Sam, 2015

Sam, Yen Yen, Ibrahim, Halijah & Saw, Leng Guan, 2015, Four new species of Scaphochlamys (Zingiberaceae) from Peninsular Malaysia, Phytotaxa 221 (1), pp. 21-34 : 21-22

1. Scaphochlamys baukensis Y.Y.Sam , sp. nov. ( Figs. 1–2 )

Scaphochlamys baukensis is different from all other species of Scaphochlamys in its broad obovate leaves, small compact rachis and tiny flowers.

Type:— PENINSULAR MALAYSIA. Terengganu: Bukit Bauk Forest Reserve, Endemic Trail , 93 m, 13 July 2007, Y. Y . Sam FRI 68955 (holotype: KEP!, isotypes: AAU!, E!, KLU!, SAN!, SING!) .

Rhizomatous herb, 30–40 cm tall. Rhizome 4–5 mm diameter, light brown internally, running horizontally on ground surface, covered by thick leaf litter. Successive shoots emerging from rhizome, 2.5–13.5 cm apart. Bladeless sheathes 2, the largest 5–6.5 cm long, hairy, dark purple brown, not persistent. Leaf 1 per shoot; sheath 1–1.5 cm long, membranous, very narrow, densely hairy, not persistent; petiole plus leaf sheath 6.5–11(19) cm long, channelled, densely covered with woolly hairs, base slightly swollen, whitish or tinged purple; lamina 17.5–20.5(–25) × 10– 11.3(–12.1) cm, obovate, coriaceous, held sub-erect, base long attenuate, apex rounded, adaxial surface dark green and glabrous, abaxial surface pale green and hairy, tip usually tinged purple. Inflorescence 7.5–10 cm long; peduncle 4.5– 6.5 cm long; rachis (2.5)3.2–4.1 × (1–1.6) 2–2.5 cm, compact, composed of (5–6)12–16 floral bracts, spirally arranged, closely overlapping. Floral bract 20–24 × 13–15 mm, boat-shaped, light green, some with purple tinge at base, sparsely hairy, more dense at the tip, margin crisped, lower half of the margin slightly inflexed but not overlapping, apex acute, open and slightly recurved. Cincinnus with at least 7 flowers in the axil of each bract. First bracteole 18–20 mm long, shorter than bract, margin involute and overlapped, 2-keeled, hairy, apex acute; subsequent bracteoles reducing in size. Flowers ca. 33 mm long, white except labellum. Calyx ca. 7 mm long, tubular, unilaterally split ca. 4 mm from apex, apex incised, glabrous except the apex. Corolla tube ca. 21 mm long; corolla lobes 7–8 × ca. 3 mm, near triangular when flattened, apex acute, margin incurved. Staminodes ca. 3.5 × 1 mm, half the length of corolla lobes, linear, apex obtuse, covered by glandular hairs on adaxial surface. Labellum ca. 10 × 8 mm, obovate, apex bilobed, cleft 2 mm from apex, covered by glandular hairs on adaxial surface, white with yellow median band and red streaks on both sides. Stamen ca. 7 mm long; covered by glandular hairs on abaxial surface; filament ca. 2 mm long, tinged red; pollen sacs ca. 4 mm long, basal spurred, dehiscing longitudinally; anther crest ca. 1 × 1 mm, extended but not recurved, trilobed, midlobe pointed. Stigma less than 0.5 mm long, funnel-shaped, hairy. Ovary ca. 2 × 1 mm, covered by long fine hairs, unilocular with 2 ovules. Epigynous glands filiform, two, ca. 4 mm long.

Etymology:—The epithet refers to the location where the species is found.

Distribution and ecology:—Endemic in Peninsular Malaysia, so far known only from one location: Bukit Bauk Forest Reserve, Terengganu. It occurs in lowland dipterocarp forest, 93–135 m elevation, on forest floor near streams, level terrain, under small canopy gaps with sparse ground vegetation.

Conservation status:—Critically Endangered, CR B2ab(iii). The area of occupancy for S. baukensis is 4 km 2 and it is only known from one location, Bukit Bauk Forest Reserve. As a result, these criteria qualify the species to be listed under the CR category ( IUCN 2012). Furthermore, the population on forest trail called “Endemic Trail” is threatened by disturbance because the site is a favourite recreation spot for local people. The clearing of undergrowth is a common practice in most recreation areas. Another population that is near to the road leading to the telecommunication tower on the summit is small and scattered. The possible disturbance is due to the clearing of an adjacent compartment of the forest reserve for the construction of a school that caused deterioration in the forest condition where the plants were found.

Additional specimen examined (paratype):— PENINSULAR MALAYSIA. Terengganu: Bukit Bauk Forest Reserve , road leading to the telecommunication tower, 135 m, 19 October 2002, Y. Y . Sam FRI 47168 ( KEP!) .

Discussion:— Scaphochlamys baukensis is unique in the genus. Its broad obovate leaves, compact rachis and tiny flowers easily distinguish it from other species. Other species with such dainty flowers and small, compact rachis are S. pennipicta Holttum (1950: 93) , S. petiolata Smith (1987: 210) , S. pusilla Sam (2010: 675) and S. reticosa Smith (1987: 209) . Both S. petiolata and S. reticosa are endemic in Bornean Sarawak whereas S. pennipicta and S. pusilla are from Peninsular Malaysia. Besides broadly obovate lamina and crisped floral bracts, there are other morphological differences that separate S. baukensis from its similar looking taxa. For example, both S. petiolata and S. reticosa have scarious floral bracts and light purple labellum as opposed to the coriaceous bracts and white labellum in S. baukensis . Scaphochlamys baukensis has red streaks beside the yellow median band on its labellum but there is no such variegation on the labellum of S. petiolata and S. reticosa .

For S. pennipicta , it has distinct leaf variegation and floral bract texture readily distinguishable from S. baukensis . Its lamina upper surface has 2 white bands while the underneath is coloured entirely red that persisted with age. In S. baukensis , there is no such variegation on the lamina upper surface and only a slight red tinge on the lamina lower surface that disappears with age. Furthermore, the coriaceous floral bracts, yellow median band and red streaks on the labellum of S. baukensis differ from the thin bracts and completely white flowers of S. pennipicta .

At first glance, the small sized S. baukensis resembled S. pusilla from which it differs in the lamina shape. Closer examination of the inflorescence revealed many differences, especially in the floral characters. The floral bracts of S. baukensis is much larger than S. pusilla (20–24 × 13–15 versus 12–19 × 5–9 mm) and the cincinnus within consists of only 1–2 flowers compared to S. pusilla which has at least 7 flowers in each cincinnus. Two other distinct characters to separate S. baukensis from S. pusilla are the size of staminodes and the structure of stigma. The length of the staminodes of S. baukensis is only half of its corolla lobes whereas the size of staminodes and corolla lobes of S. pusilla is similar. Scaphochlamys baukensis has a funnel-shaped and densely hairy stigma whilst S. pusilla has a beak-like and ciliated stigma.

Figures

FIGURE 1. Scaphochlamys baukensis. A. Habit. B. Floral bract. C. First bracteole. D. Ovary and calyx. E. Dorsal corolla lobe. F. Lateral corolla lobe. G. Staminode. H. Labellum. I. Stamen side view (I’), front view (I’’), back view (I’’’). J. Stigma front view (J’), side view (J’’). A–J from Y.Y. Sam FRI 68955 (KEP).

FIGURE 2. Scaphochlamys baukensis. A. Plants in loose clumps. B. Habit. C. Inflorescence. D. Flower. Photos by Y.Y.Sam.