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TUBULAR CAVITIES IN WHITE SNAKEROOT, EUPATORIUM RUGOSUM (ASTERACEAE)
Author(s) -
Lersten Nels R.,
Curtis John D.
Publication year - 1986
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1986.tb08546.x
Subject(s) - biology , bract , anatomy , pith , vascular bundle , lumen (anatomy) , botany , asteraceae , microbiology and biotechnology , inflorescence
Oil‐filled schizogenous cavities 0.2‐3.0 mm in length, each with a uniseriate epithelium, occur in all organs of white snakeroot ( Eupatorium rugosum ). Some epithelial cells swell, thus shrinking or occluding the cavity lumen. Foliar cavities form in staggered files in the midrib and in association with major veins. Cavities are progressively smaller and sparser in successive vein orders; the smallest ones develop as transformed bundle sheath cells in minor veins. Cavities in stems occur in irregular vertical files near vascular bundles in both cortex and pith. Leaf and stem cavities elongate variously, depending on when and where they form; in roots and floral organs, however, cavities are always short and sparse except in bracts, where they are common. Since each cavity remains discrete, we call these internal spaces ‘tubular cavities’ rather than ‘ducts’, which have generally been vaguely defined.