Bonatea steudneri (Rchb.f.) T.Durand & Schinz, Consp. Fl. Afric. 5: 90 (1894).
Homotypic Synonyms:

Habenaria steudneri Rchb.f., Otia Bot. Hamburg.: 101 (1881).
Heterotypic Synonyms:
Bicornella arabica Deflers, Voy. Yemen: 208 (1889).
Habenaria eminii Kraenzl., Bot. Jahrb. Syst. 19: 245 (1894).
Habenaria kayseri Kraenzl., Abh. Königl. Akad. Wiss. Berlin 1894: 62 (1894).
Habenaria ecaudata Kraenzl. in H.G.A.Engler (ed.), Pflanzenw. Ost-Afrikas, C: 152 (1895).
Habenaria philippsii Rolfe, Bull. Misc. Inform. Kew 1895: 227 (1895).
Habenaria arabica (Deflers) Kraenzl., Orchid. Gen. Sp. 1: 184 (1897).
Bonatea eminii (Kraenzl.) Rolfe in D.Oliver & auct. suc. (eds.), Fl. Trop. Afr. 7: 254 (1898).
Bonatea kayseri (Kraenzl.) Rolfe in D.Oliver & auct. suc. (eds.), Fl. Trop. Afr. 7: 255 (1898).
Bonatea philippsii (Rolfe) Rolfe in D.Oliver & auct. suc. (eds.), Fl. Trop. Afr. 7: 254 (1898).
Bonatea pirottae Cortesi, Ann. Bot. (Rome) 2: 362 (1904).
Bonatea arabica (Deflers) Cortesi, Ann. Bot. (Rome) 2: 363 (1905).
Bonatea ugandae Rolfe, Orchid Rev. 14: 368 (1906).
Bonatea sudanensis Rolfe, Bull. Misc. Inform. Kew 1910: 162 (1910).
Habenaria sudanensis (Rolfe) Schltr., Bot. Jahrb. Syst. 53: 508 (1915).

A large terrestrial herb, 25-1.25 cm tall; tubers several, 3-21 cm long, 1-4 cm diam., subcylindric fusiform or irregular in shape, densely tomentose. Stem erect, robust, leafy throughout its length. Leaves io-2o, up to 19 X 5.5 cm, lanceolate to ovate-elliptic, acute, sheathing at the base, the lowermost sheathlike and the uppermost bractlike. Inflorescence 3-28 cm long, 10-20 cm diam., cylindric to almost corymbose, laxly 3-30- flowered; bracts 2-5.5 cm long, lanceolate, acuminate. Flowers spreading, green and white; pedicel and ovary 4-7 cm long, slender. Dorsal sepal 2-3 X 1-2 cm, elliptic-lanceolate, acuminate, apex often recurved; lateral sepals 2-3 x I-I'5 cm, oblique, ovate-lanceolate, acuminate, the upper margin united for basal I-2 cm to the claw of the lip and the stigmatic arms. Petals bipartite almost to base; upper (posterior) lobe, 1-7-2-7 cm X 1-2 mm, adherent to dorsal sepal, linear, slightly curved; lower (anterior) lobe 3-7 cm X I mm, linear to filiform, adnate to the claw of the lip for 6-20 mm at the base. Lip 3-lobed from a long narrow claw 1 5-3 cm long; side lobes 2.5--2.8 cm X 1-2 mm, spreading; mid lobe 2-3.5 cm x 1-3 mm linear, decurved, sharply reflexed in the middle; spur io-21 cm long, dependent, narrowly cylindric, somewhat swollen apically. Column1-1-8 cm tall; stigmatic arms 2.2-3-2 cm long, clavate, porrect, attached to lip in lower 0o7-2 -2 cm; rostellar side lobes slender, 1-2 cm long, mid lobe in front of the column, 5-8 mm long, helmet-shaped with an acute incurved apiculum, margins ciliolate.
In grassland, amongst rocks, in scrub and at the edges of thickets and forest; I000-2800 m.
Bonatea steudneri has variable spur length probably owing to local adaptation to pollinators across its wide distribution range. This species has slightly smaller flowers with similar rostellum structure to Bonatea lamprophylla J.L.Stewart. It differs in its porrect, strongly deflexed lateral sepals and shorter labellum side lobes. Schelpe and Under (1999) Figure 24 C is incorrectly labelled as B. steudneri. The image more closely approximates Bonatea boltonii (Harv.) Bolus, but there is no voucher reference to confirm this.

NE. Sudan to N. KwaZulu-Natal, SW. Arabian Pen.