230 
Card. Bull. Singapore 69(2) 2017 
Microchirita involucrata in the serrate margin of the bracts and from M. rupestris in 
the much smaller size of the bracts. - TYPE: Thailand, Nan, Song Kwaw, Sakoen, 
Khao Tham Plakang, 750 m, 3 September 2006, Watthana, S. 2126 (holotype QBG; 
isotype CMU). 
Herb to 50 cm tall. Stems fleshy, sparsely glandular hairy. Leaves opposite, with the 
exception of the single basal leaf; petioles 0.1-2 cm long, glandular hairy and with 
sparse long eglandular hairs; blades lanceolate, 2-8.5 x 1-6.5 cm, 1.3-2.2 times as long 
as wide, base cordate or obtuse, apex acute, with a dimorphic indumentum of dense and 
short glandular hairs and longer and thicker eglandular hairs, margin delicately serrate, 
8-10 pairs of secondary veins in the opposite leaves, tertiary venation inconspicuous. 
Inflorescence 1-3-flowered, arising from the axil end of the petiole; peduncles 2-8 
mm long, glandular hairy; bracts fused at the base and enclosing the pedicels, 0.6-1.1 
x 0.3-0.5 mm, sessile or shortly petiolate, margin and indmentum matching those 
of the leaves; pedicels 0.8-1.2 cm long, covered in minute glandular hairs. Calyx 
zygomorphic, tube 1.5 mm dorsally, 1 mm laterally and 0.5 mm ventrally, lobes linear 
to oblanceolate, 4.5-7.5 x 0.8-2.2 mm, minutely toothed towards the apex, apex acute, 
densely glandular hairy outside and inside. Corolla 15-18 mm long, reportedly white, 
tube with a narrow basal portion, slightly curved downwards, then progressively 
broadening, externally with a minute glandular indumentum; tube c. 12.5 mm long 
dorsally, 15-16 mm ventrally, 13 mm laterally between lips; upper lobes elliptic, c. 
1.5 x 2.5 mm, lateral and lower lobes seemingly small but not measured. Stamens 
arising c. 7 mm above the corolla base; filaments glabrous, c. 3.5 mm long, S-shaped; 
anthers with a dense indumentum at the insertion, c. 1.3 x 2.5 mm, apically joined by 
a connective, thecae subparallel; lateral staminodes c. 0.5 mm long, arising c. 6.5 mm 
above the corolla base, central staminode c. 0.7 mm long, arising c. 6.5 mm above 
corolla base. Disk annular, 0.4-0.5 mm high. Pistil 12-14 mm long; ovary 5-6 mm 
long, c. 1.5 mm diameter, with minute glandular hairs throughout its length, except 
for the lowermost half millimetre, which is glabrous; style c. 6 mm long, covered in 
the same indumentum as the ovary; stigma lobes c. 1.5 mm long, glabrous. Fruit and 
seeds not seen. 
Distribution. Northern Thailand (Nan). 
Habitat. On exposed limestone. 
Provisional IUCN conservation assessment. Data Deficient DD. This species is 
only known from a single collection from a National Park. There is extensive but 
underexplored limestone in the region and more information is needed on the 
distribution of the species and on potential threats before a satisfactory conservation 
assessment can be given. 
Notes. The epithet refers to the conspicuous presence of a glandular indumentum. 
