1. Mayacaceae Kunth

    1. This family is accepted.

[NTK]

Aona, L.Y.S. (2009). Neotropical Mayacaceae.

Morphology
Description

Aquatic, perennial , rooted herbs. Leaves simple , spirally arranged, flat, sessile , without a distinct sheath , lanceolate to linear or nearly filiform , apically bidentate . Flowers axillary , solitary on short pedicels, emergent, actinomorphic , perfect, hypogynous, trimerous, with distinct calyx and corolla ; sepals 3, free , opposite, green, valvate to subvalvate; petals 3,  free , white, imbricate , short-clawed; stamens 3, alternate with petals; filaments slender, glabrous ; anthers basifixed, tetrasporangiate to bisporangiate, opening by apical pores or pore-like slits or sometimes by pores at end of a tubular apical appendage ; ovary unilocular, composed of 3 united carpels, placentation parietal ; style simple , terminal ; stigma short capitate or slightly trifid; 6-30 ovules/ carpel , bitegmic, tenuinucellate. Fruit a loculicidal capsule with 3 lines of dehiscence, each midway between a placenta ; seeds ovoid to globose , striate .

Distribution
Distribution in the Neotropics
  • Mayaca Aubl. (ca. 10 spp., Central America to Paraguay).
Diagnostic
Distinguishing characters (always present)
  • Mayacaceae are small herbs of marshes looking rather like club-mosses.
  • They have numerous spirally-arranged, apically-toothed leaves, borne scattered along the stem.
  • Pink to white apparently axillary flowers.
  • Clearly differentiated calyx and corolla.

(Stevens 2009)

Other important characters
  • Roots, stems and leaves contain vessels with scalariform perforations (Stevenson 1998).
Key differences from similar families

Differs from other aquatic plants such as:

  • Pontederiaceae, which have inflated petioles and flowers arranged in dense inflorescences.
  • Haemodoraceae, where the calyx and corolla are fused and septal nectaries present.
Useful tips for generic identification
  • See family description.
Notable genera and distinguishing features
  • Mayaca: anthers with slit or apical, poricidal dehiscence.
General Description
Status
  • Most species are native to Tropical and warm-temperate America.
  • One species occurs in tropical West Africa.
Notes on delimitation
  • Mayacaceae belongs within the Order Poales, but differ vegetatively from most of the other members of this order.
  • Anthers in some species are monothecal, the nucellar epidermis is basally thickened and the outer layer of the endosperm has proteins.
  • The inflorescence is sometimes described as being terminal, but the flowers of the Neotropical species studied seem to be axillary and associated with a broad, adaxial prophyll-like structure.
  • However, given the association of Mayacaceae with families that have scapose inflorescences with involucral bracts, the inflorescence of Mayacaceae deserves re-examination.
Number of genera

One Neotropical genus: Mayaca.

Literature
Important literature

Stevenson, D.W. 1998. Mayacaceae. In K. Kubitzki (ed.) The families and genera of vascular plants - Volume 4. Springer Verlag. Berlin, p. 294-296.

Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, February 2009 [and more or less continuously updated since]. http://www.mobot.org/MOBOT/research/APweb/.

Images

Mayacaceae Kunth appears in other Kew resources:

First published in Abh. Königl. Akad. Wiss. Berlin 1840: 93. 1842 (1842)

Accepted by

  • APG IV (2016) http://dx.doi.org/10.1111/boj.12385

Sources

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Neotropikey
Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.
http://creativecommons.org/licenses/by/3.0