Taxonomic studies on generic limits in the family Boraginaceae, tribe Cynoglosseae
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The thesis embodies the results of a taxonomic investigation of tribe Cynoglosseae of Boraginaceae subfamily Boraginoideae. The classification is a synthetic one based on maximum correlation of characters drawn primarily from studies of morphology and palynology, but also from reviews of available anatomical, embryological, cytological and chemo-taxonomic information. The thesis is divided into 28 chapters. Chapter 1 considers the position and limits of the Cynoglosseae in relation to the other tribes of subfamily Boraginoidea. Chapter 2 outlines aspects of vegetative, floral and fruit morphology. Chapter 4 consists of a discussion of the palynology of the tribe in relation to that of the family as a whole. Five major pollen groups are recognised, being those first described by Barbier & Mathez in Candollea 28: 281-323 (1973) with modification in the light of n data. The putative line of palynological evolution in the tribe ls discussed. Chapter 7 considers phytogeographical aspects, the importance and diversity of the Cynoglosseae in each continent being analysed in turn. Anatomy and embryology (Ch. 3), cytology (Ch. 5) and chemotaxonomy (Ch. 6) are also reviewed. Chapters 28 constitutes the formal systematic treatment of the tribe, beginning with a description and dichotomous key to genera (Ch. 8). Nineteen genera and 233 species are recognised (Chs. 9-27). Five genera are excluded (Ch. 28) and five described for the first time (Austrocynoglossum, Desmolopha, Eleutherostylum, Madrea, Paracaryopsis). Major revisions of the limits of Cynoglossum, Omphalodea and Paracaryum are proposed. Mattiastrum Brand is included in Parascaryum (DC.). Boiss. to form one large genus hose four constituent subgenera are linked by intermediate species. Cynoglossom is restricted to 17 species (mainly in Europe & C. Asia); most Asian and all African species are transferred to Paracynoglossom M. Popov, with three Indian species being separated as Paracaryopsis (H. Riedl) R. Mill and the Australian C. latifolium R. Br. segregated as Austrocynoglossom M. Popov ex R. Mill. Five N. American species and the Chinese C. triste Diels constitute the new genus Eleutherostylum (Brand) R.Mill. Five Mexican species of Omphalodes Miller are referred to Mimophytum Greenman, while O. erecta Johnston is elevated to generic rank as Madrea R. Mill. New infrageneric taxa are described in Rindera, Solenanthus, Pardoglossum, Cynoglossum, Paracaryum, Paracynoglossum, Omphalodes and Mimophytum, and 4 new species of Tysonia and Paracynoglossum are proposed; 85 new combination are made. The thesis is illustrated by 3 colour and 3 monochrome plates, 48 line figures, 18 maps and 52 tables.
Thesis, PhD Doctor of Philosophy
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