Petenaea

Abstract: The distribution of vestured pits in the secondary xylem of all major groups of Malvales s.l. is investigated and compared with recent circumscriptions and phylogenetic insights of the order. While the monophyly of the core Malvales, including Bombacaceae, Malvaceae s.str., Sterculiaceae, and Tiliaceae, is supported by the lack of vestured pits, the character is consistently present in three malvalean alliances that are well supported based on molecular data: (1) Bixaceae, Cochlospermaceae, and Diegodendraceae; (2) Cistaceae, Dipterocarpaceae s.l. (including Monotaceae), and Sarcolaenaceae; and (3) Thymelaeaceae s.l. (including Aquilariaceae and Gonystylaceae). Vestured pits are absent in other malvalean taxa such as Petenaea, Muntingiaceae, Neuradaceae, and Sphaerosepalaceae. Families that are now excluded from the order, such as Dirachmaceae, Elaeocarpaceae, and Huaceae also have non-vestured pits. Rudimentary vestures in Plagiopteraceae, however, do not necessarily indicate a malvalean affinity.