Mendoncia decaryi (Benoist) Magnaghi, Novon

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 : 63-65

3. Mendoncia decaryi (Benoist) Magnaghi, Novon 23:188. 2014.

Mendoncia cowanii Benoist var. decaryi Benoist, Notul. Syst. (Paris) 11:141. 1944.

TYPE.— MADAGASCAR. Toamasina: Zahamena (Réserve Naturelle Integrale 3), [ca. 17°38ʹ30ʺS, 048°50ʹ00ʺE], 23 Mar 1941, Decary 16712 (lectotype, designated by Magnaghi and Daniel, 2014: P-00091101!).

Young stems sparsely to densely pubescent with yellowish to golden-brown, erect to flexuose, unbranched, eglandular trichomes 1–3 mm long, and sometimes also with an understory of mostly erect, eglandular trichomes ˂0.05– 0.3 mm long. Leaves membranaceous to subcoriaceous, petioles to 15 mm long, pubescent like young stems, blades ovate-elliptic to elliptic, 28–123 long, 24–77 mm wide, rounded to cordate at base, acuminate to acuminate-subcaudate (sometimes abruptly so) at apex, abaxial surface (primarily major veins) bearing flexuous, eglandular trichomes like those of young stems except to 4.2 mm long and often intertwined, and sometimes also with understory trichomes like those of young stems, and rarely with tufts of woolly trichomes in axils of main veins forming domatia (see discussion below), adaxial surface pubescent (usually denser on major veins) with antrorse, eglandular trichomes 0.6– 3 mm long. Inflorescences borne in leaf axils on young, mostly herbaceous and leafy stems, solitary or opposite at nodes, dichasia 1–3 per axil, peduncles to 20 mm long, pubescent like young stems. Bracteoles purplish, persistent as fruit matures, elliptic to ovate-elliptic to ovate, 11–29. 8 mm long, 9–18. 4 mm wide, rounded at base, acute-apiculate to acuminate-subcaudate at apex, apicule or slender, tail-like apex to 6 mm long, abaxial surface densely pubescent with cauline type trichomes (except overstory trichomes to 3.5 mm long), adaxial surface mealy-glandular. Calyx densely pubescent with unbranched, eglandular trichomes 1–3 mm long. Corolla white with purplish markings, 33. 5–49 mm long, externally glabrous to mealy-glandular, tube 20–32. 5 mm long, limb 20.6–32. 4 mm diameter, upper lip 13.5 mm long with rounded or emarginate lobes 8–10 mm long and 11.2–13. 2 mm wide, lower lip 16. 5–19 mm long with rounded or emarginate lobes 9.4–13. 5 mm long and 12.2–15. 2 mm wide. Stamens 6. 3–11 mm long, ventral pair inserted 3.8 mm distal to the dorsal pair, thecae 4.4–6. 4 mm long, densely pubescent at base with a tuft of bristles 0.1– 0.3 mm long, sometimes thecae of ventral stamens with bristles along entire length, connective extending 0.3– 0.7 mm beyond thecae, extension of connective attenuate, glabrous, staminode (if present) not seen. Pollen not seen. Style 15. 3–28 mm long, pubescent near base with eglandular trichomes to 1 mm long, glabrous distally, stigma subequally to unequally 2-lobed with lobes 0.2– 0.5 mm long. Drupe subellipsoid to obovoid, 12. 5–20 mm long, 6. 5–17 mm in diameter, pubescent with golden-brown, unbranched, eglandular trichomes 0.1– 1.5 mm long.

PHENOLOGY.— Flowering: February–April; fruiting: March–September.

DISTRIBUTION AND HABITATS. — Northern and east-central Madagascar (Antananarivo, Antsiranana, Mahajanga, Toamasina; EOO = 105,283 km 2; Fig. 12 ). Plants occur in primary, montane, moist to wet, evergreen forests. Elev. 300–1400 m.

ILLUSTRATION.— Magnaghi and Daniel (2014:189, Fig. 1 ).

LOCAL NAMES.— “Tsipolitrala” (Ratovoson et al. 273); “vahimpinaomby” (Razafitsalama et al. 473); “vahipisaka” (Rakotondrafara et al. 238).

USES.— Infusion of the stems used to treat syphilis (Razafitsalama et al. 473). Williams et al. (2006; as " M. cowanii ") reported the presence of two new bioactive molecules (cytotoxic naphthoquinones) in root and stem extracts of this species.

The major distinctions between M. decaryi and M. cowanii are color and sizes of components of the corolla, as indicated in the keys to species herein. Thus, identification of plants lacking corollas can be difficult. Some of the tendencies in characters that might help to distinguish these taxa include: leaves of M. decaryi are generally thinner, higher (4–5 th) order veins more prominently protruding (or visible) on the abaxial leaf surfaces, prominent acarodomatia in axils of major veins on the abaxial leaf surface are entirely or usually absent (see below), and the apicule/narrowed, tail-like apex of the bracteoles is usually longer (up to 6 long mm vs. to 1 mm long in M. cowanii ).

Two specimens, Dorr 3538 and Morat 4776, lack adequate flowering material but possibly represent an undescribed taxon. They are included here because, like M. decaryi , they have stems, leaves, and bracteoles densely pubescent with golden-brown flexuose trichomes 1.3– 3.5 mm long that sometimes overtop a shorter layer of dense trichomes (0.8– 1 mm long) on the main veins of leaves and bracteoles. However, bracteoles on both of these specimens are smaller (10.3–10. 8 mm long, 3.5 mm wide) than those of M. decaryi , and both have some domatia present on leaves (vs. absent in other collections of M. decaryi ). Dorr 3538 bears a single corolla with unmeasurable lobes. Label data indicate white petals with purple markings, as in M. decaryi . Both specimens were collected in west-central Madagascar (west of Tsiroanomandidy), well apart from other collections in wet forests of northern and eastern portions of the country. Study of additional material is needed to clarify the taxonomic status of these collections, which are here tentatively treated as M. decaryi .

ADDITIONAL SPECIMENS EXAMINED.— MADAGASCAR. Antananarivo: Bongolava W de Tsiroanomandidy, [18°49ʹ00.012ʹʹS, 045°40ʹ00.012ʹʹE], Morat 4776 ( P) . Antsiranana: E Madagascar, N of Maroantsetra, ca. 8 km E of Sahavary, off the River Andranofotsy , Du Puy & Du Puy MB 163 (K); Sous-préfecture d’Andapa , Commune Rurale de Doany , Fokontany de Betsomanga , versant NW du Marojejy, 0.2 km au N du camp I, 14°25ʹS, 049°36ʹE, Gautier et al. 3798 (K, MO); Réserve Naturelle de Marojejy , N slopes of Ambatosoratra, 14°32ʹS, 049°41ʹE, Miller 4202 ( CAS, MO, TAN); Andranotsarabe , Befingotra , Bealampona , Andapa , 14°42ʹ20ʺS, 49°32ʹ00ʺE, Rasoavimbahoaka & Rastefanonirina 287 ( BR, MO, TAN); SW d’Andapa , Réserve Speciale d’Anjanaharibe-Sud , Ambodisatrana , aux environs des sommets, 14°32ʹ45ʺS, 049°35ʹ15ʺE, Ravelonarivo 145 ( MO) . Toamasina: Réserve Naturelle no.3 (Zahamena), Decary 16741 (P-00091100, K-000393674-photo); Betampona-Réserve Naturelle no.1, [17°55ʹS, 049°13ʹE], Decary 16924 ( P, TAN-000438-photo); Ampitanonoka à Fotsialanana, near Lac Alaotra, Herbier de la Station Agricole de L. Alaotra 2441 ( MO); W of Vavatenina, Réserve Naturelle Integrale Zahamena, forest of Amboditamenaka, 17°44ʹS, 49°00ʹE, Malcomber et al. 2516 ( MO, TAN); Sous-préfecture Vavatenina , Commune Miarinarivo, Fokontany Anamborano, limite entre Vavatenina et Toamasina II, a 500 m d’Ifasina, 17°44ʹ42ʺS, 048°58ʹ26ʺE, Rakotondrafara et al. 238 ( MO); RNI Tamatave, Rakotoniana 2875 ( P); Parc Natl. de Zahamena , Andranofantsona, Manakambahiny I, Ambodimangavalo, 17°39ʹ07ʺS, 048°58ʹ14ʺE, Ratovoson et al. 273 ( MO); Fiv. Vavatenina , Com. Ambodimangavalo, secteur 2, aux environs (hors) du Parc Azhamena, forêt Ambinanin Antsahabesahona, vers 16 km SE d’Ambarifotsy, au bord du rivière Ihofika, 17°39ʹ16ʺS, 048°, 58ʹ50ʺE, Razafitsalama 473 ( MO) . Mahajanga: 9.6 km NW of Ambohitsaratelo-Bebao ( NW of Tsiroanomandidy ), [ca. 18°18ʹ8.54ʺS, 045°32ʹ18.84ʺE], Dorr 3538 ( MO, TAN).

Figures

FIGURE 12. Map of Madagascar showing distributions of Mendoncia decaryi and M. delphina, and map of Madagascar and Mayotte showing distribution of M. flagellaris.

FIGURE 1. Phylogenetic relationships among genera of Acanthaceae sub- family Thunbergioideae and Avicennia. OW = Old World, NW = New World. Adapted from Borg et al. (2008).