Mendonciaceae

Primary tabs

Mendonciaceae

Description

Herbaceous or suffrutescent, counterclockwise twining vines. Stems articulated when young, glabrous or pubescent with simple or stellate, glandular and eglandular trichomes; cystoliths lacking. Leaves opposite, simple, entire, exstipulate, petiolate. Inflorescences of solitary or clustered flowers in leaf axils, each pedicellate and subtended by 2 large, flat or keeled, spathelike bracteoles (= bracts previously used by this and other authors); bracteoles green, variously shaped and vestured, often equaling corolla tube, valvate, often partially connivent or connate, remaining closed around flower, often widely spreading during fruiting. Flowers zygomorphic, bisexual; calyx inconspicuous, annular or cupular, truncate to irregularly dentate or lobed; corolla sympetalous, ± hypocrateriform, not inflated above, contorted, whitish, greenish, or reddish, often with purplish markings within, tube cylindric to funnelform, limb subequally 5-lobed or 2-lipped with upper lip 2-lobed and lower lip 3-lobed, lobes spreading or reflexed; stamens 4, didynamous, included, attached to corolla tube alternate with lobes, anthers 2-thecouswith parallel, subequal to unequal thecae, ± pubescent at base, dehiscing longitudinally or by subapical pores or slits; pollen spherical, 5-6-colporate; staminode, if present, 1, inconspicuous; nectar-disk prominent, cupular, around base of ovary; ovary superior, 2-locular, or one locule more or less reduced or even suppressed, ovules 2 in each locule, or 2 in one fertile locule, collateral, funiculus of ordinary type, neither thickened nor otherwise much modified, style filiform, stigma shallowly and unequally 2-lobed. Fruits drupaceous, ovoid to ellipsoid, mesocarp fleshy, endocarp osseous; seeds 1-2, embryo dicotyledonous, cotyledons twice folded, endosperm wanting.

Distribution

Africa: Guianas: present Madagascar: present Pantropical: present southern Brazil: present southern Mexico: present tropical western Africa: present
Pantropical family of 2 genera, Mendoncia with about 50-60 species and Anomacanthus R. Good, a monotypic genus in west-central tropical Africa. The species of Mendoncia are sparingly distributed in tropical western Africa and Madagascar and from southern Mexico to southern Brazil; 6 species occur in the Guianas.

Studied:

M. aspera, M. hoffmannseggiana, M. microchlamys (Colombia).

New synonyms:

  • Mendoncia perrottetiana Nees to Mendoncia bivalvis (L. f.) Merr.
  • Mendoncia sellowiana Nees var. perrottetiana (Nees) Miquel to Mendoncia bivalvis (L. f.) Merr.

Lectotypification:

  • Mendoncia squamuligera Nees

Wood

All species of Mendoncia, the sole genus of the family present in S America, are lianas.
Though mature stems of Mendoncia show an almost regular, shallowly fissured appearance they show on cross section a strongly abnormal structure consisting of numerous woody bundles embedded in non-lignified tissue. In young stems it starts with a 4-lobed woody cylinder. By ingrowth of the parenchymatic tissue and splitting of the woody branches the irregularity gets more pronounced, resulting in small patches of non-lignified parenchyma within the woody cylinders with or without contact with the enveloping parenchyma. In this parenchymatic tissue isolated thick-walled, long, acicular fibres, occur and locally some phloem, difficult to trace. Most of the large parenchyma cells contain numerous thin acicular crystals.
Growth rings absent.
Vessels of two sizes: wide and narrow, distribution diffuse, crowded. Large ones 9 (7-12) per sq. mm, mainly solitary, few in radial or tangential multiples of 2-3, outline round to oval, diameter 200-300 (150-400) µm, narrow ones 25-60 µm, some intermediate, usually in radial or tangential multiples of 2-3. Vessel-member length 450 (240-650) µm with a tendency toward greater length in the narrow vessels. Intervascular pits alternate to opposite, the border angular, slits included, occasionally confluent, 9 µm wide. Vessel-ray pitting partly similar, but for the greater part large, irregularly elongate.
Tracheids with a narrow diameter often present near the wide vessels.
Rays 1-2-seriate, 5-8 per mm. Heterogeneous, most cells square and upright; 15-30 µm wide, up to 15 cells (500) µm high.
Parenchyma paratracheal as a vasicentric ring of one cell layer. Strands mostly 3-6-celled, some up to 10 cells, often fusiform cells present. Contents: occasionally cystoliths.
Ground tissue of non-septate and few septate fibres and fibre-tracheids. Diameter 20-24 µm, walls thin, 2-3 µm. Pits simple, numerous in radial and tangential walls. Average length 770 (480-1060) µm. F/V ratio 1.72.
A. Carlquist, S. & S. Zona., Wood anatomy of Acanthaceae: A survey in Aliso 12. 1988, B. Dechamps, R., Etude anatomique de bois d'Amérique du sud. I. Acanthaceae à Lecythidaceae. in Ann. Mus. Roy. Afr. Centr., Tervuren Sc. Econ. No. 10. 1979, C. Détienne, P. & P. Jacquet. - in Atlas des bois de l'Amazonie et des régions voisines. 1983, D. Détienne, P., P. Jacquet & A. Mariaux. in Manuel d'identification des bois tropicaux 3. Guyane française. 1982, E. Hess, R.W., Identification of New World timbers. Part I. in Trop. Woods 86. 1946, F. Hess, R.W., New genera of American woods in Trop. Woods 96. 1950, G. Metcalfe, C.R. & L. Chalk. in Anatomy of the Dicotyledons II. 1950, H. Niesemann, H.W. - in Das anormale Dickenwachstum von Mendoncia velloziana Mart. und Afromendoncia lindaviana Gilg. 1927, I. Obaton, M., Les lianes ligneuses à structure anormale des forêts denses d'Afrique occidentale in Anns. Sci. nat. Bot. 1. 1960, J. Outer, R.W. den & W.L.N. van Veenendaal., Wood anatomy of Uncarina leandrii H. Humb. (Pedaliaceae) and its relation to Bignoniaceae. in IAWA Bull. n.s. 4. 1983, K. Schenck, H., Biologie und Anatomie der Lianen. Teil II: Beiträge zur Anatomie der Lianen in Schimpers bot. Mitth. aus den Tropen Hft. 5. 1893, L. Solereder, H. - in Systematische Anatomie der Dicotyledonen. 1899, M. Solereder, H. in Systematische Anatomie der Dicotyledonen Ergänzungsband. 1908, N. Tchouproff, O., Anatomie syst. des Acanthaceae in Bull. Herb. Boiss. 3. 1895, O. Tchouproff, O., Etude sur les causes qui déterminent le fractionnement du bois axial chez Mendoncia schomburgkiana Nees et sur l'origine et le développement des tissues cicatrisants in Bull. Herb. Boiss. 5. 1897, P. Welle, B.J.H. ter., Cystoliths in the secondary xylem of Sparattanthelium (Hernandiaceae) in IAWA Bull. n.s. 1. 1980

Notes

Traditionally the Mendonciaceae have been included in the Acanthaceae, but they lack both the cystoliths and the specialized mechanism of seed-dispersal which characterize that family (Cronquist, 1981). Most current specialists in the Acanthaceae (Profice, 1989; Daniel, 1992), including myself (Wasshausen, 1989), tend to include the family in the Acanthaceae. For a somewhat detailed examination of this relationship see Brummitt (1989), "Against separating Mendonciaceae from Acanthaceae." According to Daniel (1992), "most workers have distinguished species primarily on the basis of vegetative and bracteolar characters.".