The Winter Cassia (Cassia bicapsularis Linnaeus) is a legume native to tropical America, but is now pantropical. It is one of those surprising shrubs; when other plants are going dormant, it bursts into yellow. The Cassia are a confusing bunch with an estimated 500 species. In Florida, Cassia are caterpillar host plants for five of the nine native species of Sulphur butterflies.

The Sulphur butterflies are generally yellow or yellow and black butterflies, but in several species the females have a white form or the butterflies vary with the seasons. The Large Orange Sulphur female is white with gray markings. The Sleepy Orange Sulphur has an orange and black form seen in the winter months and a yellow and black form seen during the summer.

The caterpillars of the Sulphurs are capable of variable camouflage. The caterpillars tend to be mostly green if they are feeding on the foliage of the Cassia, but will be mostly to completely yellow if feeding on the flowers. Whether the caterpillar is colored by the plant pigments is not known.

The chrysalis is often colored yellow, green, or brownish. It appears like a damaged or caterpillar-chewed leaf. A single strand of silk holds the chrysalis at an angle to the branch.

Eight of the nine species in Florida use legumes as hosts for the larvae. It is presumed that the caterpillars sequester a toxic or, at least, distasteful chemical from the plants.

Casa de Cassia has seven great photographs of Sulphur butterflies and caterpillars. The caterpillars are well hidden even in the open. To view the photographs, click on the link:

http://www.jaymer.com/garden/cassia/butterflies/butterflies.htm

Click on the individual links listed and look carefully.