Strobilanthes fusca J.R.I.Wood

Wood, J.R.I. & Scotland, R.W. 2009. New and little-known species of Strobilanthes (Acanthaceae) from India and South East Asia. Kew Bulletin 64: 3. DOI: https://doi.org/10.1007/s12225-009-9098-2

Morphology General Habit

Isophyllous shrub to 0.5 m high

Morphology Stem

Stems glabrous, young branchlets reddish

Morphology Leaves

Leaves shortly petiolate; petioles 0 – 5 mm long, glabrous; lamina 5 – 12 × 1.5 – 3.3 cm, oblong-elliptic, acuminate to an obtuse apex, tapered to the base, the margins undulate, paler and slightly scabrid beneath, glabrous and with prominent cystoliths on both surfaces

Morphology Reproductive morphology Inflorescences

Inflorescence a small terminal panicle up to 7 cm long; rachis and branches densely pilose with short, glandular hairs; branches trifurcate with 2 – 3 imbricate flower pairs; bracts at inflorescence branching points 15 – 20 × 3 – 4 mm, oblong, tapered at both ends, fuscous, densely pilose with short glandular hairs; floral bracts 10 – 13 × 4 – 5 mm, elliptic to oblong-elliptic, acute and narrowed at both ends, fuscous, densely pilose with short, gland-tipped hairs, ciliate on the margins with a few scattered long, white multicellular setae; bracteoles absent; calyx 8 – 10 mm long, divided into 5 lobes to c. 3 mm above the base, lobes narrowly lanceolate, finely attenuate, shortly glandular-pilose, one lobe c. 2 mm longer than the others, interior surface glabrous or with a few short hairs; corolla c. 2 cm long, white, glabrous outside, straight, the tube 5 – 6 × 2 mm, then expanded to c. 8 mm, 5-lobed, the lobes ovate, obtuse, c. 2.5 mm long; fertile stamens 4, all included, filaments glabrous, the longer pair c. 4 mm long, the shorter pair c. 2 mm long; anthers 2 mm long; pollen prolate, 55 × 35 μm, 3-colporate, pseudocolpate, c. 12-ribbed, the tectum between the pseudocolpi consisting of a coarse irregular reticulum with a punctate tectum between the course reticulum (Plate 1K); style c. 12 mm long, sparsely pilose; ovary pilose

Morphology Reproductive morphology Fruits

Capsule 11 × 1.75 mm, elliptic in outline, glandular-pilose, 4-seeded; seeds 1.5 × 1 mm, pilose with a small but distinct glabrous areole

Distribution

On Luzon Island in the Philippines.

Ecology

In forest on basic soil; 300 – 400 m.

Conservation

Data insufficient but clearly very rare and probably Endangered (EN).

Note

This species appears to be most closely related to Strobilanthes schomburgkii (Craib) J. R. I. Wood from Thailand. It is similar in facies and both species lack bracteoles. However, the inflorescence is clearly terminal and branched although rather small and compact. The bracts are narrowly elliptic rather than ovate, fuscous in colour and covered in an indumentum of short, dense glandular hairs. The long white, multicellular setae which cover the bracts of S. schomburgkii are restricted to scattered cilia along the margins in S. fusca. The calyx is glabrous inside and the central posterior lobe is noticeably longer than the others. It is the only species, which Bremekamp would have placed in Sericocalyx known from the Philippines.