Mendoncia Vell. ex Vand., Fl. Lusit.

Magnaghi, Emily B. & Daniel, Thomas F., 2017, Systematics of Mendoncia (Acanthaceae: Thunbergioideae) in the Paleotropics, Proceedings of the California Academy of Sciences 64 (3), pp. 37-94 : 52-54

Mendoncia Vell. ex Vand., Fl. Lusit.

Brasil. 43. 1788. LECTOTYPE (designated by Leonard 1951).— M. aspera Ruiz et Pav. (as “ Mendozia aspera ”).

Engelia Nees in Alph. de Candolle, Prodr. 11:721. 1847. LECTOTYPE (designated by Leonard 1951).— E. tovarensis Klotzsch. & H. Karst. ex Nees.

Monachochlamys Baker, J. Linn. Soc., Bot. 20:217. 1883 (“1884”). TYPE.— M. flagellaris Baker.

Afromendoncia Gilg ex Lindau, Bot. Jahrb. Syst. 17:111. 1893. TYPE.— A. lindaviana Gilg ex Lindau.

Lirayea Pierre, Bull. Mus. Hist. Nat. (Paris) 2:341. 1896. TYPE.— L. floribunda Pierre.

Lianas. Young stems subquadrate to quadrate-sulcate, glabrous or pubescent with eglandular, branched (stellate and dendritic) or unbranched trichomes. Leaves (membranaceous to) subcoriaceous to coriaceous, petiolate, petioles glabrous or pubescent, blades (lanceolate to) ovate to subdeltate to elliptic to subcircular to oblong to obovate to obcordate, surfaces somewhat discolorous (darker green adaxially than abaxially), glabrous or sparsely to densely pubescent with eglandular trichomes, especially along midvein, margin sometimes ± revolute. Inflorescences of 1–10 (–20), pedunculate, 1-flowered dichasia borne in axils of leaves on young, herbaceous shoots (most species) or at leafless nodes on older woody stems (i.e., M. lindaviana and M. phytocrenoides ) or in axils of subfoliose bracts on axillary or terminal racemes (i.e., often in M. flagellaris ); flowers sessile or short-pedicellate in axil of 2 isomorphic bracteoles. Bracteoles opposite, sessile, (lanceolate to) ovate to elliptic to subcircular to oblong to obovate, rounded to acute and often apiculate at apex, truncate to rounded to subcordate at base, sometimes with a pair of prominent, bulbous, white protuberances basally (i.e., M. flagellaris ) on the abaxial surface, bracteolar pair at least partially connate and filled with watery fluid through most of anthesis in most (or all?) species. Calyx a rigid, entire or variously lobed (sometimes with a single prominent lobe, and/or irregularly and shallowly multi-lobed), often undulating, annular or cupular ring surrounding a ± fleshy nectar disc (evident after corolla dehisces). Corolla funnelform, white, white with purple spots, pink, or purple, glabrous (or inconspicuously mealy-glandular) on external surface, glabrous or with glandular trichomes on internal surface of throat, tube ampliate distally into a throat, which sometimes (e.g., M. combretoides ) narrows toward mouth, limb bilabiate with upper lip 2-lobed, lower lip 3-lobed, lobes convolute (left-contort) in bud, entire to emarginate at apex. Stamens 4, didynamous, inserted near the middle of corolla tube, included or barely exserted from mouth of corolla, anthers bithecous, thecae linear, subequally to unequally inserted, parallel, densely pubescent at least at base with a tuft of pointed or papilla-like bristles, dehiscing by apical pore or slit, connective usually extending 0. 2–3 mm beyond apex of thecae, 1 (–2) staminode(s) often present. Pollen (4–) 5 (–6)- brevicolpate, interapertural surfaces rugulate. Ovary situated on a prominent, ± fleshy or annular nectar disc, style included in or exserted from mouth of corolla, stigma equally to subequally 2-lobed or ± capitate. Drupes (when dry) ovoid to ellipsoid to oblong to spherical to obovoid, glabrous or pubescent, 1-seeded. Seed bony, generally shaped like and slightly smaller than drupe.

A genus of about 90 species occurring primarily in the Neotropics, but with 10 species in tropical Africa, Madagascar, and on the island of Mayotte in the Comoros Archipelago. The generic description is derived exclusively from the Paleotropical species.

Key to Paleotropical Taxa of Mendoncia

(see Appendix 3 for regional keys to taxa in Africa and Madagascar / Mayotte)

1a. Young stems, petioles, peduncles, and abaxial surface of bracteoles pubescent with at least some branched (stellate to dendritic) trichomes; Africa............................. 2

1b. Young stems, petioles, peduncles, and abaxial surface of bracteoles glabrous or pubescent with unbranched trichomes only; Africa and Madagascar................................ 3

2a. Inflorescences borne in leaf axils on young, mostly herbaceous, leafy stems; corollas 17. 5–22 mm long; style 16–18 mm long; drupes mealy-glandular (lacking elongate trichomes); leaves 44–133 mm long and 23–86 mm wide.............................. M. combretoides

2b. Inflorescences mostly borne at naked nodes on older, woody, leafless stems; corollas 29.3–31. 8 mm long; style 22. 8–27 mm long; drupes pubescent with eglandular trichomes to 0.6 mm long; leaves 86–200 mm long and 57–114 mm wide...................... M. phytocrenoides

3a. Inflorescences mostly borne on peg-like, woody, sometimes branched short-shoots at naked nodes on older, woody, leafless stems; drupe oblong (symmetrical); Africa... M. lindaviana

3b. Inflorescences borne in leaf axils on young, mostly herbaceous, leafy stems; drupe variously shaped, but rarely oblong (asymmetrical or symmetrical); Africa and Madagascar........ 4

4a. Ovary and drupe glabrous or mealy-glandular (i.e., with inconspicuous, sessile glands mostly <0.05 mm in diameter), lacking elongate, eglandular trichomes; calyx glabrous or sparsely pubescent................................................................. 5

4b. Ovary and drupe pubescent with elongate, eglandular trichomes; calyx usually densely pubescent...................................................................... 8

5a. Bracteoles mostly persistent in fruit, usually pubescent with trichomes up to 3 mm long; drupe 6.8–11. 8 mm long, ± irregularly shaped (overall obovoid) and widest at or just below the truncate to shallowly acute (symmetrically or asymmetrically) apex; Africa....... M. gilgiana

5b. Bracteoles mostly deciduous in fruit, if pubescent, then with trichomes up to 1.2 mm long; drupe 9. 5–30 mm long, variously shaped and sometimes obovoid, but not as described above; Madagascar................................................................ 6

6a. Corollas pink or light to dark purple, 20–35 mm long, upper lip 10–17 mm long; bracteoles usually lacking dense pubescence at apex of adaxial surface; extension of connective beyond anther thecae pubescent with glandular and eglandular trichomes 0.1– 0.3 mm long; drupe subspherical to spherical, 14. 8–25 mm in diameter; northern Madagascar........ M. vinciflora

6b. Corollas white and usually with purple markings near base of limb and/or throat (rarely purplish in M. delphina ), 8–18. 5 mm long, upper lip 2–12. 5 mm long; bracteoles with dense pubescence at apex of adaxial surface; extension of connective beyond anther thecae (if present) glabrous to minutely glandular; drupe ovoid-ellipsoid to ellipsoid to spherical to obovoid, 6–15. 7 mm in diameter; widespread............................................ 7

7a. Dichasia 1–2 in axils of leaves; apex of leaf blade acuminate to caudate, with tail-like apex to 12 mm long; bracteoles yellowish, lacking a pair of conspicuous, whitish, bulbous, gall-like basal protuberances; pollen 5-aperturate; southern Madagascar.............. M. delphina

7b. Dichasia 1–4 (–8) in axils of leaves or commonly in axils of bracts in an a raceme to 15 cm long; apex of leaf blade (acuminate) to acute to rounded to truncate to retuse, and sometimes with an apiculum to 1.6 mm long; bracteoles green, often with a pair of conspicuous, whitish, bulbous, gall-like basal protuberances; pollen mostly 4-aperturate; widespread.. M. flagellaris

8a. Corollas 13. 2–19 mm long, tube 10–14 mm long; leaf blades mostly with length:width 1.4–1.7.................................................................... M. kely

8b. Corollas 26–49 mm long, tube 20–38; leaf blades mostly with length:width 1.7–2.8....... 9

9a. Corollas white with purplish markings, limb 20.6–32. 4 mm in diameter, upper lip 13.5 mm long with lobes 8–10 mm long and 11.2–13. 2 mm wide, lower lip 16. 5–19 mm long with lobes 9.4–13. 5 mm long and 12.2–15. 2 mm wide............................... M. decaryi

9b. Corollas light pink to dark pink (sometimes whitish externally), limb 6–21 mm in diameter, upper lip 1. 8–10 mm long with lobes 1.8– 7.4 mm long and 3.7–8. 6 mm wide, lower lip 3–12. 4 mm long with lobes 2.2–7. 5 mm long and 3.4–9. 1 mm wide........................ 10

10a. Young stems, petioles, abaxial surfaces of leaf blades and bracteoles, and peduncles subglabrous and/or pubescent with erect to flexuose to antrorse trichomes, underlying surfaces plainly visible; corolla with upper lip 4. 4–10 mm long and lobes of lower lip 3.5–7. 5 mm long and 3.5–9. 1 mm wide..................................... M. cowanii var. cowanii

10b. Young stems, petioles, abaxial surfaces of leaf blades and bracteoles, and peduncles densely pubescent with flexuose-interwoven trichomes such that underlying surfaces not visible (or only partially so on abaxial surface of leaf blades); corolla with upper lip 1.8– 3.6 mm long and lobes of lower lip 2.2–3. 3 mm long and 3.4– 3.5 mm wide......... M. cowanii var. coursii