The bracts in this plant (fig. 66) are thin, papery inflorescence bracts, not entirely comparable with any of the above because of the distinctive inflorescences of this plant. The three bundles are each ensheathed with a fibrous bundle sheath.
Obvious distinctive modes of bract structure occur in the taxa mentioned
above. The lack of mesophyll differentiation in Orectanthe and Achlyphila
bracts is intersting, for considerable differentiation occurs in comparable bracts
of Abolboda. In Abolboda, particular types of bract structure (depending at
least in part on the location of the bract on the plant and the level of section
Avithin a bract) suggests caution in the formulation of differences among the
species of Abolboda in bract anatomy.
With the exception of Achljiphila, all the taxa studied here have keeled sepals. Some Xyridaecae, such as Orectanthe, have both keeled and non-keeled sepals. The non-keeled sepals were found to have approximately the same structure as the winged portion of a keeled sepal (compare, for example, figures 21 and 64), so that separate descriptions are not necessary. The chief variation of significance is the relative distribution and presence of sclerenchyma and (if present) chlorenchyma. To a large extent, the distribution of these tissues in comparison with non-photosynthetic parenchyma cells provides distinctions of taxonomic importance. The patterns are best summarized in terms of species.