Mendoncia phytocrenoides (Gilg ex Lindau) Benoist, Mem. Soc. Linn.

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 : 84-86

9. Mendoncia phytocrenoides (Gilg ex Lindau) Benoist, Mem. Soc. Linn. Normandie, n.s.i. 2:44. 1928.

Afromendoncia phytocrenoides Gilg ex Lindau, Bot. Jahrb. Syst. 17:112. 1893. Thunbergia phytocrenoides T. Anderson ex Lindau, Bot. Jahrb. Syst. 17:113. 1893, pro syn. Monachochlamys phytocrenoides (Gilg ex Lindau) S. Moore, J. Bot. 67:227, in clavi. 1929.

TYPE.— GABON. Estuaire: Muni River, Lat. 1°N, Sep 1862, Mann 1839 (lectotype, designated here: K-000393679!; isolectotypes: P-00435325!, K-000393681!, K-000393680-photo!, W-0006693- photo!, S-SG128-photo!).

Afromendoncia iodioides S. Moore, Cat. Pl. Oban 74. 1913. Monachochlamys iodioides (S. Moore) S. Moore, J. Bot. 67:227, in clavi. 1929. Mendoncia iodioides (S. Moore) Heine, Kew Bull. 16:180. 1962. Mendoncia phytocrenoides var. iodioides (S. Moore) Heine (as “ ioides ”), Fl. Gabon 13:74. 1966.

TYPE. — NIGERIA. Cross River: Oban [05°13ʹ27.64ʺN, 008°33ʹ18.53ʺE], 1911, Talbot & Talbot 388 (holotype: BM-000930925 -photo!; isotype: K-000393684 -photo!).

Mendoncia letestui Benoist, Notul. Syst. (Paris) 11:143. 1944.

TYPE. — GABON: Ogooue-Lolo: région de Lastourville , Moughounda [ca. 00°51ʹ57.94ʺS, 012°46ʹ57.20ʺE], 14 Aug 1930, Le Testu 8250 (lectotype, designated here: P-00435326 -photo!; isolectotypes: P-00435327 !, BR-000000629448 -photo!, BR-000000629442 -photo!; K!; probable isolectotype: IFAN-16076 - photo!) .

Young stems evenly and densely pubescent with an overstory of flexuose to recurved, golden-brown or straw-colored, unbranched trichomes 1. 4–5 mm long and a sparse to dense understory (sometimes ± inconspicuous) of branched (stellate to dendritic) trichomes 0.2– 0.4 mm long, older stems sparsely pubescent to glabrate. Leaves subcoriaceous, petioles to 46 mm long, pubescent like young stems, blades broadly ovate to subcircular to elliptic to obovate-elliptic, 86–200 mm long, 57–114 mm wide, rounded to subcordate at base, subacute to acute at apex, abaxial surface pubescent with erect to flexuose, unbranched trichomes 1.3– 2.7 mm long (especially on main veins), these sometimes overtopping an understory (sometimes very sparse) of branched trichomes 0.2– 0.4 mm long (and sometimes very sparse and inconspicuous erect, glandular trichomes 0.1 mm long, as well), adaxial surface glabrous to ± mealy or pubescent along proximal portion of midvein with trichomes like those of abaxial surface. Inflorescences borne on older, woody, mostly leafless stems, solitary or opposite at nodes, dichasia 1–3 (–5) per axil, peduncles to 30 mm long, pubescent like young stems. Bracteoles red to purplish (or brown when dry), mostly persistent in fruit, subcircular to ovate to elliptic to lanceolate, 12–37. 8 mm long, 6.5–23. 4 mm wide, rounded at base, acute-apiculate at apex, apiculum (usually obscured by pubescence) 1–2. 8 mm long, abaxial surface and margin pubescent with flexuose to antrorse, mostly unbranched, golden-brown trichomes 1.5– 5.5 mm long, these overtopping an understory of branched trichomes 0.1– 1 mm long, adaxial surface ± mealy and sometimes with scattered trichomes to 1.5 mm long, major veins sometimes ± protruding abaxially resulting in a channeled appearance. Calyx pubescent with branched trichomes (fide Schönenberger and Endress 1998). Corolla white, 29.3–31. 8 mm long, externally glabrous, tube 23.4–24.9 (–30) mm long, apically ampliate, limb 9.3–14. 6 mm in diameter, upper lip 4.4– 4.9 mm long with emarginate lobes 2.7– 4.2 mm long and 4–5. 2 mm wide, lower lip 6. 5–7 mm long with emarginate lobes 4.4–5. 3 mm long and 3.5– 5.9 mm wide. Stamens 8.7–24. 8 mm long, ventral pair inserted 1–2 mm distal to dorsal pair, thecae 2.4 mm long, pubescent at base with a tuft of bristles 0.1– 0.2 mm long, these and glandular trichomes sometimes extending down the filament, connective extending 2–3 mm beyond thecae, connective extension attenuate, pubescent with glandular and eglandular trichomes 0.05–1 mm long, staminode 0.5– 1.3 mm long. Pollen 5-colpate, E = 29–31 µm, P = 29 µm, P:E = 0.967–1.007, C = 6.8–8.6 µm, C: P = 0.234–0.295, rugulae smooth to very sparsely microverrucate to microgemmate. Style 22. 8–27 mm long, stigma subequally 2-lobed, lobes 0.1– 0.4 mm long. Drupe ovoid to subspherical, 17.6–24. 8 mm long, 12.2–15. 3 mm in diameter, pubescent with erect, mostly unbranched (and with a few scattered, apically branched) trichomes 0.1– 0.6 mm long.

PHENOLOGY.— Flowering: February–September; fruiting: all year.

DISTRIBUTION AND HABITATS.— Tropical central Africa ( Cameroon, Congo-Kinshasa, Gabon, Nigeria; EOO = 689,906 km 2; Fig. 18 ). Plants occur in wet, evergreen forests. Elev. 200–850 m. The species likely also occurs in the mainland African portion of Equatorial Guinea, which lies between occurrences in Cameroon and Gabon.

ILLUSTRATIONS.— Thiselton-Dyer (1896:t. 2427); Heine (1966:75, Pl. 15).

Although only a single collection (Mann 1839) of Afromendoncia phytocrenoides was cited in the protologue, several specimens of it exist. It is unknown whether Lindau had a specimen at B that is no longer extant, but it is clear that he saw and annotated materials at K, where three syntypes are extant. One of these from Hooker’s herbarium (K-00393679) was annotated as “ holotype ” by Breteler in 2013. Because this specimen bears the greatest amount of original label data as well as both Anderson’s manuscript name and that of Gilg (both noted in the protologue), we designate this specimen as the lectotype for A. phytocrenoides . Similarly only a single collection of Mendoncia letestui was cited in the progologue, but multiple specimens of it exist, with at least two at P that bear the name in Benoist’s handwriting. From these syntypes, P-00435326, with more complete locality information, is chosen as the lectotype.

We include Mendoncia phytocrenoides var. iodioides in the synonymy of M. phytocrenoides . The distinction between these varieties was primarily the presence or absence of a layer of dendritic to stellate trichomes on the leaves and bracteoles which underlies a layer of longer, simple, antrorse-appressed trichomes. Heine (1966) recognized var. iodioides and distinguished it from var. phytocrenoides on the basis of its pubescence consisting principally of stellate trichomes (vs. pubescence principally consisting of simple trichomes mixed with branched or substellate trichomes). This feature is not consistent, and sometimes trichomes on leaves, bracteoles, and drupes of mature specimens fall off. Also, the geographic ranges of the putative varieties overlap. With the limited availability of specimens (19) and thus limited flowering material, a comparison of the floral features of the two varieties was difficult. Until additional collections are studied, the stated differences between the putative varieties appear to be insufficient to warrant their recognition at this time.

ADDITIONAL SPECIMENS EXAMINED.— CAMEROON. Central: près Ndokononoro , à 15 km SW de Ndikiniméki, [ca. 04°38ʹ13.10ʺN, 010°46ʹ00.59ʺE], Letouzey 10888 ( P) . East: près Djouo , rive gauche du Dja (45 km SSE de Mesaména) [ca. 03°21ʹ25.88ʺN, 012°56ʹ17.08ʺE], Letouzey 4306 (K, P) . Littoral: Ebo Forest Research Station (proposed Natl. Park), north transect, Osborne & Beheng 118 (K) . Southwest: Gazette-Kupe Village , Cable S. 3884 ( MO) ; main trail from Kupe village toward Mt. Kupe , Etuge M. 2769 ( MO) ; Mount Kupe, SW slope, main trail to the top from Kupe village [ca. 04°46ʹ44.72ʺN, 009°40ʹ47ʺE], Schönenberger 50 (F, K, P) . CONGO-KINSHASA. North-Kivu: Kabunga Terr., Walikale [ca. 01°24ʹ55.03ʺS, 028° 03ʹ43.23ʺ], Leonard 1792 ( BR) . South-Kivu: Kalehe Terr., réserve IRSAC à Irangi, km 110, route Kavumu–Walikale, Christiaensen 1796 ( BR) . GABON. Estuaire: Akoga, N des Monts de Cristal , Hallé, 892 ( P) . Ogooue-Ivindo: 15 km SW Makokou , [ca. 00°28ʹ23.47ʺN, 012°44ʹ59.25ʺE], Hallé 2654 ( P) ; Belinga [ca. 01°07ʹ58.16ʺN, 013°11ʹ50.27ʺE], Hallé, 3358 (K, P) .

Figures

FIGURE 18. Map of central Africa showing distribution of Mendoncia phytocrenoides.