The systematic relevance of fruit and seed structure in Bersama and Melianthus (Melianthaceae) |
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Authors: | A B Doweld |
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Institution: | (1) National Institute of Carpology (Gaertnerian Institution), Moscow, Russian Federation, RU |
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Abstract: | The fruit and seed anatomy and morphology of the two genera Bersama and Melianthus (Melianthaceae, Sapindales) have been studied in an effort to clarify their systematic position. On the basis of the differences
in pericarp and seed anatomy as well as in other exomorphic characters the segregation of Bersama into a distinct family Bersamaceae is supported. Evidence mainly from seed anatomy and morphology emphasizes the anomaly
of the traditional inclusion of Bersama and Melianthus in the Sapindales, since they have a distinct seed-coat structure and seed vascularization. The fruit and seed anatomy does
not confirm any relationships with alternatively suggested exo-mesotestal Lardizabalaceae. The exotestal seed coats of Bersama and Melianthus with a differentiated palisade of Malpighian cells in the exotesta, dimerous raphal vascular skeleton, abundant endosperm,
and a small differentiated straight embryo show a resemblance with the exotestal albuminous seeds of Rhamnaceae and Elaeagnaceae.
Using also additional data on fruit, floral and vegetative morphology it is suggested that Bersamaceae with Melianthaceae
and Rhamnaceae/Elaeagnaceae constitute a distinct relict side-branch of exo-mesotestal rosidaceous ancestry, the new order
Melianthales in the superorder Rhamnanae (Rosidae). The formerly suggested relationship of this side-branch to exotegmic Malvales
is not supported by seed anatomy. The affinity with exotegmic Celastrales, which are considered as a possible connecting link
between archaic exo-mesotestal Rosales and exotestal Rhamnales/Elaeagnales, is also found untenable.
Received May 12, 2000 Accepted December 7, 2000 |
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Keywords: | : Carpology fruit pericarp seed anatomy phylogenetic relationships Melianthaceae Bersama Melianthus |
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