Friday, October 27, 2017

[Botany • 2017] Morphological Phylogeny of Tradescantia L. (Commelinaceae) Sheds Light On A New Infrageneric Classification for the Genus and Novelties on the Systematics of subtribe Tradescantiinae


 E & I Tradescantia zanonia (L.) Sw. Tripogandra diuretica (Mart.) Handlos 
Tradescantia praetermissa M.Pell Tradescantia zebrina Heynh. ex Bosse.
 
   J &  Tradescantia fluminensis Tradescantia cerinthoides Kunth.
All photos by M.O.O. Pellegrini, except G by H. Huaylla.


Abstract
Throughout the years, three infrageneric classifications were proposed for Tradescantia along with several informal groups and species complexes. The current infrageneric classification accepts 12 sections – with T. sect. Tradescantia being further divided into four series – and assimilates many concepts adopted by previous authors. Recent molecular-based phylogenetic studies indicate that the currently accepted sections might not represent monophyletic groups within Tradescantia. Based on newly gathered morphological data on the group, complemented with available micromorphological, cytological and phytochemical data, I present the first morphology-based evolutionary hypothesis for Tradescantia. Furthermore, I reduce subtribe Thyrsantheminae to a synonym of subtribe Tradescantiinae, and propose a new infrageneric classification for Tradescantia, based on the total evidence of the present morphological phylogeny, in accordance to the previously published molecular data.

Keywords:  Commelinales, Elasis, Gibasis, inflorescence morphology, Tradescantieae, spiderworts

Figure 1. Some macromorphological characters used in the phylogenetic analysis.
 A subpetiolate leaf (Character 8) and asymmetrical base (Character 16), in Tradescantia tenella Kunth B complicate leaves (Character 8), in Tradescantia crassula Link & Otto. impressed secondary veins (Character 19), in Tradescantia fluminensis Vell predominantly axillar to thyrse-like synflorescence (Character 24), in Callisia repens (Jacq.) L. synflorescence with two paraclades (Character 26), in Tradescantia zanonia (L.) Sw. contracted cincinni (Character 34), fused back to back (Character 35), vestigial cincinni bracts (Character 38), flower display of 60° (Character 48), shorter antesepalous stamens (Character 72), sigmoid filaments (Character 73), and zygomorphic androecium (Character 76), in Tripogandra diuretica (Mart.) Handlos supernumerary cincinni bracts (Character 37), in Tradescantia praetermissa M.Pell cincinni bracts saccate at base (Character 43), tubular flower (Character 47), fused petals (Character 60), clawed petals (Character 62), shorter antesepalous stamens (Character 72), connective expanded and transversally linear (Characters 77–80), round anther sacs (Characters 81–82), pollen white in vivo (Character 83), and trilobate stigma (Character 91), in Tradescantia zebrina Heynh. ex Bosse. I tubular flower (Character 47), pedicels geniculate at anthesis and pre-anthesis (Character 51), fused sepals (Character 53), filaments bearded with sparse and short hairs at mid-length (Characters 66–71), shorter antesepalous stamens (Character 72), connective expanded and transversally linear (Characters 77–80), round anther sacs (Characters 81–82), pollen white in vivo (Character 83), and trilobate stigma (Character 91), in T. zanonia sepals all keeled (Character 56), in T. fluminensis filaments basally bearded with dense and long hairs (Characters 66–71), connective expanded and rhomboid (Characters 77–80), anther sacs ellipsoid (Characters 81–82), and pollen yellow in vivo (Character 83), in T. fluminensis pistil longer than the androecium (Character 86) and punctate (Character 91), in Tradescantia cerinthoides Kunth. All photos by M.O.O. Pellegrini, except G by H. Huaylla.

Marco O. O. Pellegrini. 2017. Morphological Phylogeny of Tradescantia L. (Commelinaceae) sheds light on A New Infrageneric Classification for the Genus and Novelties on the Systematics of subtribe Tradescantiinae. PhytoKeys. 89: 11-72.  DOI: 10.3897/phytokeys.89.20388

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