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Scyphostegia borneensis

Mac H. Alford
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Containing group: Malpighiales

Introduction

Scyphostegia borneensis is an enigmatic species endemic to the northern part of Borneo. Its unusual combination of dioecy, basal placentation, 3-merous flowers, and telescoping inflorescence bracts have puzzled botanists, and the species has been placed by different authors in several different and distantly-related families, including Monimiaceae, Moraceae, Tamaricaceae, and Flacourtiaceae. Most workers after the early 1900s placed it in its own monotypic family, the Scyphostegiaceae. Analyses of plastid DNA sequences have clearly demonstrated that Scyphostegia borneensis belongs in Malpighiales and is a close relative of Salicaceae. Like many Malpighiales, its leaves are toothed and stipulate and its seeds are arillate. Like Salicaceae, the anther dehiscence is extrorse, and some authors (e.g., Chase et al., 2002) place it in a broader Salicaceae. Because it differs from other Salicaceae in its telescoping bracts, connate and tubular perianth, connate stamens, basal placentation, and arillate seeds, it is probably best to continue to place Scyphostegia borneensis in its own family, the Scyphostegiaceae.

Characteristics

Shrubs or small trees. Leaves simple, alternate, toothed, stipulate. Dioecious. Inflorescences terminal, consisting of racemosely-arranged spikes or racemes, each spike or raceme a series of flowers within telescoped tubular bracts, the lower bracts subtending a single flower, the terminal bract subtending two. Perianth connate, tubular, with 6 lobes, 3 in an outer whorl (calyx) and 3 in an inner whorl (corolla), the whorls more or less equal in female flowers but the inner whorl conspicuously shorter in male flowers. Male flowers with 3 extrastaminal disk glands and with 3 connate stamens, opposite the petals, anther dehiscence longitudinal and extrorse. Female flowers lacking disk glands, with a gynoecium consisting of a superior, unilocular, urceolate ovary (appearing somewhat fig-like) with basal placentation and numerous erect, anatropous ovules; style and stigma not evident, perhaps depressed into the center. Fruits fleshy capsules deshicent from the apex, reminiscent of Monimiaceae. Seeds numerous, arillate; embryos straight, cotyledons foliaceous.

Other Names for Scyphostegia borneensis

References

Chase, M. W., S. Zmarzty, M. D. Lledó, K. J. Wurdack, S. M. Swensen, and M. F. Fay. 2002. When in doubt, put it in Flacourtiaceae: a molecular phylogenetic analysis based on plastid rbcL DNA sequences. Kew Bulletin 57: 141-181.

Swamy, B. G. L. 1953. On the floral structure of Scyphostegia. Proceedings of the National Institute of Science of India. Part B: Biological Science 19: 127-142.

van Heel, W. A. 1967. Anatomical and ontogenetic investigations on the morphology of the flowers and the fruit of Scyphostegia borneensis Stapf (Scyphostegiaceae). Blumea 15: 107-125.

van Steenis, C. G. G. J. 1957. Scyphostegiaceae. Pp. 297-299 in Vol. 5, Flora Malesiana, Series 1.

Title Illustrations
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Scientific Name Scyphostegia borneensis
Location Malaysia: Sabah: Mt. Kinabalu
Specimen Condition Live Specimen
Identified By Reed S. Beaman
Sex Male
Copyright © 2004 Reed S. Beaman
About This Page

Mac H. Alford
University of Southern Mississippi, Hattiesburg, Mississippi, USA

Correspondence regarding this page should be directed to Mac H. Alford at

Page: Tree of Life Scyphostegia borneensis. Authored by Mac H. Alford. The TEXT of this page is licensed under the Creative Commons Attribution-NonCommercial License - Version 3.0. Note that images and other media featured on this page are each governed by their own license, and they may or may not be available for reuse. Click on an image or a media link to access the media data window, which provides the relevant licensing information. For the general terms and conditions of ToL material reuse and redistribution, please see the Tree of Life Copyright Policies.

Citing this page:

Alford, Mac H. 2007. Scyphostegia borneensis. Version 06 February 2007 (under construction). http://tolweb.org/Scyphostegia_borneensis/68360/2007.02.06 in The Tree of Life Web Project, http://tolweb.org/

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