Abstract
Herbarium specimens of Tillandsia do not reveal adequate amounts of information about floral characteristics, so classifications have been based on vegetative characteristics and few floral characters. The principal objective of this study was to evaluate the homogeneity and delimitation of subgen. Tillandsia. Exsertion of the stamens, used to distinguish the subgenus from closely related subgen. Allardtia, was evaluated, as were several other characters now used at the species level. Living specimens of more than one-half of the species in subgen. Tillandsia and a few from subgen. Allardtia were examined and suites of floral characters that distinguish groups, unrelated to the current subgeneric boundaries, were revealed. Several methods were used to evaluate the coherence of these groups. Numerical taxonomic techniques, including unweighted pair group method arithmetic averages and principal component analysis, were used to evaluate phenetic affinities, based on 113 characters and various subsets of characters. Floral characters produced distinct clusters, whereas vegetative characters did not. Vegetative characters did, however, support floral characters. Trichomes were viewed by scanning electron microscopy and were found rich in characteristics of taxonomic interest. Natural hybridization was investigated. Pollen of non-hybrid and hybrid specimens were stained and the percentage of viable grains used to determine the degree of sterility of hybrids. Principal component analysis and scatter diagrams were used to show relationships among hybrids and parental types. Pollination related characteristics were discussed, evolutionary trends reviewed, and an unspecialized tillandsioid precursor reconstructed....
Gardner, Cecelia Su (1982). A systematic study of Tillandsia subgenus Tillandsia. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -385479.