Neotropical Hamamelidaceae

Jon L.R. Every

Royal Botanic Gardens, Kew, UK. 

Description

Trees or shrubs, evergreen, indumentum of mostly sclerified stellate or tufted trichomes. Leaves alternate, distichous, simple, petiolate, margins entire; venation pinnate, campylodromous, secondary veins terminating in the teeth or three-veined at base (Matudaea Lundell); stipules small, deciduous, distinct, scarious, borne on stem adjacent to petiole. Inflorescences terminal and axillary, dense spherical heads or racemes of unisexual rudimentary flowers. Flowers small, hermaphroditic, unisexual or andromonoecious; sepals absent or rarely 5; petals absent; stamens 2-numerous often with prolonged connective, anthers basifixed, covered by stellate trichomes, mostly dehiscing by valves or by a longitudinal slit; ovary inferior, partially inferior or superior Matudaea, carpels 2, syncarpous, often free at apex, bi-locular, styles 2, stigma 2, decurrent. Fruit woody, ovoid (stalked and sessile in same infructescence) capsular, often aggregate, exocarps leathery, endocarp bony. Seeds one per carpel, dispersed by ballistic ejection, hard and black or brown, smooth, resemble pine nuts when dry.

Notes on delimitation

  • Placed in the Saxifragales, closely related to Daphniphylaceae and Cercidiphyllaceae (APG2, 2003).
  • Forms an order along with the Neotropical Crassulaceae, Grossulariaceae, and Saxifragaceae, plus Iteaceae and Pterostemonaceae.
  • Considered to be part of the woody clade along with the Neotropical Altingiaceae and Haloragaceae sensu lato (expanded to include Tetracarpaceae, Penthoraceae and Aphanopetalum Endl.) plus the Asian, Cercidiphyllaceae and Daphniphyllaceae. (Jian et al 2008).

Distribution in the Neotropics

  • Mexico to Colombia.
  • Cool upland regions, wet mixed forest.
  • Molinadendron Endress (includes Neotropical Distylium Sieb. & Zucc.) with three Neotropical species: M. guatemalense (Radlk. ex Harms) P.K. Endress, M. hondurense (Standl.) P.K. Endress and M. sinaloense (Standl. & Gentry) P.K. Endress distributed from Costa Rica to Mexico (Sinaloa).
  • Matudaea Lundell with two species: M. trinerva Lundell and M. hirsuta Lundell occurring in Honduras and through to Central Mexico.

Distinguishing characters (always present)

Key differences from similar families

  • Altingiaceae (Hamamelidaceae p.p.) represented in the Neotropics by Liquidamber styraciflua L. are deciduous with leaves spirally arranged and contain resin canals in their bark.

Number of genera

  • Two: Matudaea and  Molinadendron.

Notable genera and distinguishing features

Molinadendron Endress:

  • Evergreen trees or shrubs.
  • Branches with 1-2 prophylls.
  • Conspicuous galls sometimes present.
  • Petals absent.
  • Carpels with 1 ovule.
  • Stigmas (2), large and decurrent.

Matudaea Lundell:

  • Evergreen trees.
  • Multicellular glandular hairs in the blade margin of primary leaves, stipules and bracts.
  • Branches with 2 prophylls.
  • Leaves triplinerved.
  • Inflorescences condensed panicles or botryoids (each axis terminated by a flower).
  • Flowers bisexual.
  • Sepals absent.
  • Petals absent.
  • 2 fused bracts subtend the individual flower.
  • Stamens 12-24, polyandrous.
  • Anthers opening by 2 valves.
  • Ovary superior.
  • Carpels with 1 ovule.
  • Large, decurrent stigma.

Status

  • Native.

Important literature

APG II, 2003. An update of the Angiosperm Phylogeny group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society 141(4): 399-436.

Endress, P. K. 1993. Hamamelidaceae. In: Kubitzki, K., Fohwer, J. G., and Bittrich, V.(eds) Families and genera of vascular plants. Volume 2. Flowering plants. Dicotyledons. pp322-331. Springer-Verlag, Berlin.

Jian, S. Soltis, P. S., Gitzendanner, M. A., Moore, M. J., Li, R., Hendry, T. A., Qiu, Y. L. Dhingra, A., Bell, C. D., & Douglas E. Soltis, D. E. 2008. Resolving an ancient, rapid radiation in Saxifragales. Systematic Biology. 57(1): 38-57.

Judd, W. S., Campbell, C. S., Kellogg, E. A., Stevens, P. F., Donoghue, M. J. 2008. Plant Systematics: a phylogenetic approach 3rd ed. pp 342-344. Sinauer Associates, Massachusetts.

Maas, P.J.M. & Westra, L.Y. Th. 2005. Neotropical Plant Families. 3rd ed., p.147. A.R.G. Gantner Verlag K.G., Ruggell.

Mabberley, D. J. 2008. Mabberley's Plant-book. 3rd ed. p. 388. Cambridge University Press, Cambridge.

Standley, P. C. & Steyermark, J. A. 1946. Flora of Guatemala Fieldiana, Bot. 24(4): 426-430.

Stevens, P.F. 2008. Angiosperm Phylogeny Website. Version 9 onwards. http://www.mobot.org/MOBOT/research/APweb/.

Stevenson, D.W. 2004. Hamamelidaceae. In: Smith, N., Mori, S.A., Henderson, A., Stevenson, D.W. and Heald, S.V. (eds). Flowering Plants of the Neotropics. pp.179-180. The New York Botanical Garden, Princeton University Press, Princeton.

Watson, L. & Dallwitz, M.J. 1992 onwards. The Families of Flowering Plants: Descriptions, Illustrations, Identification, and Information Retrieval. Version 3rd March 2009. http://delta-intkey.com

How to cite

Every, J.L.R. (2009). Neotropical Hamamelidaceae. 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/Hamamelidaceae.htm.