Leaf Anatomy and Systematics of New World Velloziaceae

During a survey of the vegetative anatomy of the Velloziaceae it became quite clear that the taxonomy of the American species seems to be correlated with anatomical characters that are used to distinguish genera in the family, especially in studies by Smith (1962), but that taxonomic treatments of the African species have not been based on a critical evaluation of morphological characters. The first major attempt to remedy this situation was the publication of a revision of the Old World species of Vellozia by Greves (1921). She indicated that the outgrowths on the external ovary walls are sufficiently constant and characteristic to afford a simple classification and that it is not necessary to rely solely on the perianth and stamens as major characters. Earlier, Baker (1898) had treated all the African species under section Xerophyta of Vellozia in the family Amaryllideae, thus following his classification in Bentham & Hooker, 'Genera Plantarum' (i88o). Hutchinson's (1959) treatment essentially follows Baker's classification. In their 'Checklist of the flowering plants and ferns of the Transvaal and Swaziland', Burtt-Davy & Pott-Leendertz (I912: 121), although aware of the undesirability of publishing new combinations in a checklist, transferred to the genus Barbacenia several species described earlier in Vellozia. They made these changes without giving any taxonomic reasons as it was assumed at the time that an account of the family was about to be published in Germany. Such a mass transfer of names was not supported by other botanists (cf. Bullock, 1966). Hutchinson (I959) was likewise aware of the unsatisfactory state of the taxonomy of this family and stressed the need for careful monographic studies. For the American Velloziaceae, Smith's (1962) classification was based on whether the anthers are basifixed (Vellozia) or dorsifixed (Barbacenia and Barbaceniopsis). This classification seems more logical and satisfactory to me since it accords well with the distinctive sclerenchyma distribution in the leaves of this family (Ayensu, I967b & 1968). The present investigation, therefore, is undertaken with the hope that an eventual monographer will take cognizance of the importance of vegetative anatomy in the taxonomy of the Velloziaceae. In his synopsis of the African species of Xerophyta, Baker (1875) claimed that the genus Vellozia was published by Vandelli after Jussieu had named similar plants under Xerophyta. However, it is now known that Vellozia Vandelli (1788) antedates Xerophyta Jussieu (1789) by one year. (See Bullock, 1966, for further information.)