Fabales

 Bay cedar Suriana maritima, photographed by B. Navez.

Belongs within: Fabidae.
Contains: Polygalaceae, Leguminosae.

The Fabales are a clade of flowering plants supported primarily by molecular data. Within the Fabales, the greater number of species belong to the clade Fabaceae or Leguminosae, the legumes. The majority of remaining Fabales belong to the Polygalaceae; the Surianaceae and Quillaja are both small assemblages.

Quillaja is a small southern South American genus of trees bearing large, pentamerous flowers with a thick, flesh disc lining the receptacle and produced into lobes adnate to the sepals. The soapbark Q. saponaria gets its vernacular name from the presence of saponins in its inner bark. Its wood is used in cabinet-making and the tree is a source of scent for cosmetics (Wikipedia). Quillaja saponaria historically formed dense forests in Chilean valleys but these have largely given way to pasture.

The Surianaceae are a group of shrub and trees characterised by the absence of nectaries and the presence of a layer of mucilage around the ovules (Angiosperm Phylogeny Website). The bay cedar Suriana maritima is pantropical and coastal in distribution. Its nut-like fruits can remain buoyant in sea water for a number of months, allowing for its wide dispersal. Suriana maritima is disinguished by being densely pubescent with both simple and glandular trichomes. Other Surianaceae are either glabrous or possess more scattered trichomes. The remaining genera of Surianaceae are more geographically restricted: Stylobasium and Guilhoylia are endemic to Australia whereas Recchia is found in Mexico. Recchia has carpels borne on a short gynophore. Stylobasium bears apetalous, polygamous flowers and has leaves with stomata on both upper and lower surfaces. The two Stylobasium species are found in dry, sandy habitats in Western Australia and the Northern Territory. Guilhoylia monostylis bears flowers with yellow petals and its fruit are a berry.

Synapomorphies (from Angiosperm Phylogeny Website): Ellagic acid absent; vessel elements with simple perforation plates; wood often fluorescing; styloids present; calyx initiation helical; corolla clawed; carpels free; embryo green.

<==Fabales [Fabanae, Fabineae]
    |--Quillaja [Quillajaceae]WM09
    |    `--Q. saponariaCP13
    `--+--+--PolygalaceaeWM09
       |  `--LeguminosaeCP13
       `--SurianaceaeWM09
            |  i. s.: Recchia mexicanaT00, OB11
            |--Suriana maritimaCP13
            `--+--Guilhoylia monostylisCP13
               `--Stylobasium [Stylobasiaceae]CP13
                    |--S. australeK90
                    `--S. spathulatumCP13

*Type species of generic name indicated

References

[CP13] Cardoso, D., R. T. Pennington, L. P. de Queiroz, J. S. Boatwright, B.-E. Van Wyk, M. F. Wojciechowski & M. Lavin. 2013. Reconstructing the deep-branching relationships of the papilionoid legumes. South African Journal of Botany 89: 58–75.

[K90] Keighery, G. J. 1990. Vegetation and flora of Shark Bay, Western Australia. In: Berry, P. F., S. D. Bradshaw & B. R. Wilson (eds) Research in Shark Bay: Report of the France-Australe Bicentenary Expedition Committee pp. 61–87. Western Australian Museum.

[OB11] Orenstein, R. I., & D. Brewer. 2011. Family Cardinalidae (cardinals). In: Hoyo, J. del, A. Elliott & D. A. Christie (eds) Handbook of the Birds of the World vol. 16. Tanagers to New World Blackbirds pp. 330–427. Lynx Edicions: Barcelona.

[T00] Thorne, R. F. 2000. The classification and geography of the flowering plants: dicotyledons of the class Angiospermae (subclasses Magnoliidae, Ranunculidae, Caryophyllidae, Dilleniidae, Rosidae, Asteridae, and Lamiidae). The Botanical Review 66: 441–647.

[WM09] Wang, H., M. J. Moore, P. S. Soltis, C. D. Bell, S. F. Brockington, R. Alexandre, C. C. Davis, M. Latvis, S. R. Manchester & D. E. Soltis. 2009. Rosid radiation and the rapid rise of angiosperm-dominated forests. Proceedings of the National Academy of Sciences of the USA 106 (10): 3853–3858.

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