Anatomy and Morphology of the Seed Coat in the Texas Species of Argemone (Papaveraceae)
Date
2022-05
Authors
Conway, Shelby
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Abstract
Argemone is one of the largest genera within Papaveraceae, comprising 32 species of annual, biennial, or perennial herbs. The most recent complete taxonomic revision of the Texas species of Argemone is included in the work of Ownbey, dating back to 1958, who recognized eight species occurring in the state: A. aenea, A. albiflora, A. aurantiaca, A. chisosensis, A. mexicana, A. polyanthemos, A. sanguinea, and A. squarrosa. Ownbey used a variety of morphological characters to delimit species within the genus, including petal, latex, stamen and stigma color; presence or absence of clasping leaves; shape of the bud and capsule; presence or absence of prickles on foliage bracts or on stems; and seed dimensions, and most treatments of the genus in published Texas floras have been based on Ownbey’s work. Several authors, however, have noted that Ownbey’s taxonomic distinctions are not necessarily always clear due, at least in part, to the largely continuous morphological variation seen in many of these characters. Because studies of seed coat morphology have often proven useful in the delimitation of taxa (including other genera in Papaveraceae) and in providing data for the generation of phylogenetic hypotheses, I chose to study whether or not morphological and anatomical features of the seed coat would prove useful for distinguishing among the Texas species of this genus.
Seed morphology was examined using light and scanning electron microscopy, while standard botanical histological procedures were used to study development of the seed coat. Although the seeds of all Texas species of Argemone are similar in gross morphology, consistent differences in seed size and shape, surface microsculpturing patterns, relative prominence of the hilum, raphe, and chalazal umbo, and certain
anatomical features appear to provide characters useful for species delimitation.
Description
Keywords
Argemone, Seed coat, Anatomy, Morphology, Prickly poppies
Citation
Conway, S. (2022). <i>Anatomy and morphology of the seed coat in the Texas species of Argemone (Papaveraceae)</i> (Unpublished thesis). Texas State University, San Marcos, Texas.