Document Type

Article

Publication Date

2018

DOI

10.2179/17-122

Publication Title

Castanea

Volume

83

Issue

2

Pages

263-269

Abstract

The unique morphology of quillworts has received limited attention, and such studies have been limited to only a few species. Our extensive field work during the past two decades has revealed variation in the structures of the plant, including the rhizomorph, scales, phyllopodia, and abscission caps. Polarity of the axes of southeastern quillwort rhizomorphs varies from discoid (most species), to elongate, to upright with axis branching in several species. In species of intermittent streams, these branched rhizomorphs produce plantlets that break off in running water. Scales are tiny brown or black structures in alternating whorls with sporophylls (leaves). They are often overlooked and easily removed when rinsing specimens. Found in most southeastern terrestrial/amphibious species, scales are absent from aquatic species. Scales are distinct from phyllopodia, the sclerified bases of sporophylls, but intermediates between scales and phyllopodia occur. Not all species with scales have phyllopodia. Although scales cannot be used for determination of species, their presence or absence is of taxonomic value. Research on southeastern Isoetes phylogeny could help determine which of the rhizomorph and scale characters are plesiomorphic.

Comments

Rebecca D. Bray died 21 January while this paper was in review. She was the beloved Curator of the Herbarium at Old Dominion University for many years where she generously volunteered her time curating the collection and caring for innumerable students through her widely sought sage advice and patient, listening ear. Rebecca was part of the Isoetes research group and her fastidious cytological techniques provided chromosome counts for all known southeastern quillworts. Dr. Bray is sorely missed. This paper memorializes her contributions to mentoring students and understanding the enigmatic quillworts. LJM

Rights

© 2018 Southern Appalachian Botanical Society.

Included with the kind written permission of the publisher.

Original Publication Citation

Bray, R. D., Schafran, P. W., & Musselman, L. J. (2018). Interesting, provocative, and enigmatic: Morphological observations on southeastern quillworts (Isoetes Isoetaceae, Lycopodiophyta). Castanea, 83(2), 263-269. https://doi.org/10.2179/17-122

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