Comparative morphology of the leaf epidermis in the genera Codonanthe (Martius) Hanstein and Nematanthus Schrader (Gesneriaceae)*

Abstract

The leaf epidermis of 14 species ofCodonanthe and 10 species of Nematanthus has been examined. Species of Codonanthe section Codonanthe are geographically restricted to south-eastern Brazil, and are diploid. They possess multicellular-uniseriate nonglandular trichomes, glandular trichomes with a four-celled head and a short body, anisocytic stomata and lack extrafloral nectaries. Species of Codonanthe section Spathuliformae and Codonanthe subgenus Codonanthella are distributed from southern Mexico through Central America to north-western South America and are tetraploid. They possess unicellular non-glandular trichomes (except C. caribaea), glandular trichomes with a two-celled head (except C. caribaea) and a short body, anisocytic stomata and extrafloral nectaries (except C. caribaea). All Nematanthus species are distributed in south-eastern Brazil and are diploid (N=8). Six species of Nematanthus consistently have multicellular-uniseriate nonglandular trichomes, glandular trichomes with a four-celled head and a short (unicellular) or long (multicellular) body, anisocytic stomata and lack extrafloral nectaries. Four species of Nematanthus have multicellular-uniseriate non-glandular trichomes, glandular trichomes with a head of more than four cells and a short body, anisocytic and helicocytic stomata and lack extrafloral nectaries.