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Comparative Vegetative Anatomy And Systematics Of Laeliinae (Orchidaceae), William Louis Stern, Barbara S. Carlsward
Comparative Vegetative Anatomy And Systematics Of Laeliinae (Orchidaceae), William Louis Stern, Barbara S. Carlsward
Barbara S. Carlsward
Laeliinae are one of the most prominent orchid subtribes, with c. 40 genera and nearly 1500 species, and contain a disparate group of taxa with widely varying morphological features. There does not appear to be a complex of characters to which one can refer in order to delineate the subtribe as a whole. Thus, it was thought that vegetative anatomy might provide clues to the monophyly of the group. The microscopic structure of the leaves, stems and roots of representatives of most of the genera was studied. It was concluded that the anatomy lacks overall uniformity and that vegetative characters …
Vegetative Anatomy And Systematics Of Triphorinae (Orchidaceae), Barbara S. Carlsward, William Louis Stern
Vegetative Anatomy And Systematics Of Triphorinae (Orchidaceae), Barbara S. Carlsward, William Louis Stern
Barbara S. Carlsward
Triphorinae represents a group of three anatomically simple genera, the structural features of which are unspecialized. The anomocytic stomatal pattern occurs in all genera; it predominates in Triphora . A foliar hypodermis, sclerenchyma, fibre bundles and stegmata are absent. The mesophyll is homogeneous. The exodermal and endodermal cells in the roots are entirely thin-walled and tilosomes are absent. However, there are anatomical modifications that appear to be unique: root hairs in Monophyllorchis are borne on velamenal buttresses and, in Psilochilus , they arise endogenously. In the root vascular system of Psilochilus , the metaxylem occurs as a circumferential band. The …