Bonatea boltonii (Harv.) Bolus, J. Linn. Soc., Bot. 19: 340 (1882).
Habenaria boltonii Harv., Thes. Cap. 1: 55 (1860).
Habenaria bonatea var. boltonii (Harv.) Bolus, Icon. Orchid. Austro-Afric. 2: t. 45 (1911), nom. superfl.
Erect, decumbent or scandent terrestrial herbs, 100-750 mm tall; tubers 1-8, spreading, elongate-oblong, tomentose. Stem robust, 95-740 x 3.5-11.0 mm. Leaves 5-13, lax to dense, cauline, lower sheathing, blades reduced, oblong-lanceolate to widely-ovate, acute to acuminate, margins entire, smooth to undulate, 19-178 x 9-40 mm. Inflorescence cylindrical, 74-191 x 67-132 mm, lax to dense, 3-20flowered; bracts similar to upper leaves, sheathing, ovate-lanceolate to ovate-oblong, acuminate to apiculate, 16.5-43.5 x 6.0-17.0 mm. Flowers spreading, green and white, pedicel and ovary sub-erect, 3059 mm long. Dorsal sepal green, sub-erect to erect, elliptical-ovate, galeate, acute to acuminate, 12.5-18.5 x 4-7 mm; lateral sepals green, patent, slightly deflexed, oblong-lanceolate to oblong-ovate, acute to apiculate, base oblique, margins weakly to strongly revolute with acute tooth on lower margin, 10.0-20.5 x 4-8 mm, adnate to lip and stigmatic processes for 4.0-6.5 mm. Petals upper lobe green, erect, narrowly-falcate, acute to acuminate, 9.5-18.0 x 1-4 mm, adnate to dorsal sepal, lower lobe white with green tip, spreading horizontally, weakly deflexed, weakly to strongly falcate, linear to linear-lanceolate, tip curved, acuminate, 11.0-24(-27.5) x 0.5-2.0(2.5) mm, adnate to claw of lip for 1.5-4.0 mm. Lip green, claw 6.5-12.0 mm, median lobe descending, geniculate, sometimes apically recurved, linear-lanceolate to narrowly-oblong, acute to acuminate, 727 x 1-3 mm, lateral lobes descending, diverging, falcate, linearlanceolate, tips curved, acuminate, 10.5-32.0 x 0.5-3.0 mm; spur toothed, 27-51 mm long, clavate apex 7.0-14.5 mm long. Anther erect, acute, 4.5-7.0 mm long, canals slender, 6.5-11.0 mm long. Stigmatic processes very spathulate, projecting forwards and deflexed, sub-parallel, 8.5-15.0 mm long, base adnate to lip. Rostellum 3-lobed, base auriculate, median lobe cucullate, acute to acuminate, margin ciliate, 5-9 mm long, lateral lobes linear, fused to anther canals, projecting forwards to sub-erect 20°, sub-parallel, 2.0-3.5 mm long. Flowering period: rarely August to November, December to March.
Grassland, savannah and dunes in full sun, rarely in forest and thicket, at near sea level to 1900 m altitude.
Plants are generally short in stature, often with glaucous leaves. This taxon however, can reach heights comparable with B. antennifera and Bonatea speciosa (L.f.) Willd. when growing in tall vegetation such as forest margins and mixed grassland. Bonatea boltonii and B. antennifera are distinguished by a critical quantitative divide occurring at 15 mm for stigmatic process length and 24 mm for lower petal lobe length, with B. boltonii falling below the divide. Posture of the lower petal lobe and labellum side lobe are also significantly different in the species - both projecting forward, ascending in B. antennifera, whilst lateral, horizontal petal lobes and descending labellum side lobes occur in B. boltonii.
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