Research Training Program

A comparative study of spathes of eight species of Commelina (family Commelinaceae) was conducted. This large genus has been found to be troublesome because of the similarity in form and morphology of many of the species within it. For this reason, it was intended in this study to examine characters anatomically of one of the structures found in all species of this genus, the spathe. The spathe is a leaf-like reproductive structure that either subtends or encloses the inflorescence. Employing standard laboratory techniques for anatomical examination including epidermal scrapes, paraffin embedding, and wholemount clearing, observations were made on several characters comparing the spathes of the different species. Scanning electron microscopy and photomicrography were used to document significant characters. Observations were also made on characters that were shared or differed from the leaves of the same species. This was done in the hope of identifying characters unique to spathes that could be used to separate the species of this genus. A leaf anatomy study had been conducted by Hardy in 1994, and this was used as the reference for the spathe/leaf comparison. The unusual nature of one species, C. 1ongicapsa, was especially noted. The presence of solely adaxial stomata, incredibly large glandular microhairs, and high concentrations of calcium oxalate crystals within the microhairs set this species apart from other members of the group.