Neotropical Thismiaceae

Hiltje Maas-van de Kamer and Paul J.M. Maas

National Herbarium, Wageningen University Branch, the Netherlands.  

Description

Myco-heterotrophic ("saprophytic"), small herbs without chlorophyll; root system tuberous or rarely cylindrical, roots filiform, glabrous; stems unbranched. Leaves (2-)4, alternate, sessile, simple, entire, scale-like, sometimes forming a rosette just below the flower. Flowers terminal, solitary, 5-20 mm long, bisexual, actinomorphic to sometimes zygomorphic, the cylindric to urceolate floral tube with a circular throat, surrounded by an ornamented annulus; tepals 6, forming 2 whorls each of different shape and size, sometimes connate into a miter; stamens 6, pendent, often alternating with 6 interstaminal lobes, filaments short, anthers dithecal, extrorse, longitudinally dehiscent, connective dilated; perianth basallly circumscissile; style 1, cylindrical, much shorter than the floral tube, 3-branched, each branch bearing a stigma, or unbranched with 1 capitate stigma; ovary inferior, 1-locular with 3 parietal placentas or with 3 placental columns in the center, septal nectaries absent. Fruit cup-shaped, fleshy, crowned by a rim formed by the persistent basal part of the floral tube, dehiscent by withering of the wall. Seeds many, small and "dustlike", (narrowly) ellipsoid to ovoid.

Notes on delimitation

Distribution in the Neotropics

  • Thismiaceae: from Costa Rica in the North to Bolivia and SE Brazil in the South; absent in the West Indian Islands.
  • Tiputinia P.E.Berry & C.L.Woodw. - Ecuador.
  • Thismia Griff. - from Costa Rica in the North to Bolivia and SE Brazil in the South; absent in the West Indian Islands.

Other important characters

  • Flowers sometimes zygomophic; one of the whorls of tepals often provided with long and filiform appendages, sometimes with a swollen top (osmophores?).

Key differences from similar families

Formerly placed in Burmanniaceae from which it differs by having:

  • Circumscissile perianth.
  • 6 pendent (instead of 3 erect) stamens.
  • Short style far exceeded by the floral tube.

(For differences with Triuridaceae see under Burmanniaceae).

Number of genera

  • 2 genera: Thismia (12 spp.) and Tiputinia (1 sp.).

Useful tips for generic identification

Key to genera of the Neotropical Thismiaceae

1. Filaments with distinct, fimbriate appendages ... Tiputinia.
1. Filaments without fimbriate appendages ... Thismia.

Notable genera and distinguishing features

  • Thismiaceae are very much undercollected in the Neotropics and of most species (except for the quite common Thismia panamensis (Standl.) Jonker) only 1 collection has been known. Two species from the Alto Macahe (in the state of Rio de Janeiro, Brazil) were only collected once each in 1889.

Status

  • Native.

Important literature

Maas, P.J.M., H. Maas-van de Kamer, J. van Benthem, H.C.M. Snelders, and T. Rübsamnen. 1986. Burmanniaceae. Flora Neotropica 42: 1-189 (but particularly 142-189).

Merckx, V. 2008. Myco-heterotrophy in Dioscoreales. Systematics and Evolution. pp. 1-217. Leuven, Belgium.

How to cite

Maas-van de Kamer, H. & Maas, P.J.M. (2009). Neotropical Thismiaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Thismiaceae.htm.