Caldesia

Lore & Background

The genus name Caldesia honors Ludovico (Luigi) Caldesi, an Italian politician and botanist who lived from 1821 to 1884. The genus was circumscribed by Filippo Parlatore in 1860 in Flora Italica, volume 3, on page 598.

Leaves are all basal, floating or aerial, ovate to elliptical, cordate or subcordate. Flowers are hermaphrodite, arranged in racemes or panicles, with 6 to 11 stamens. Carpels are few or numerous in a single whorl, free, each with one ovule; styles are subventral. Fruitlets are drupaceous, with a woody endocarp and spongy exocarp, swollen, with a short subventral beak, and may be smooth or bear tubercles or spines.

Selected species include the fossil Caldesia brandoniana †, Caldesia grandis from Assam, Bangladesh, and southern China, and Caldesia oligococca with several varieties distributed across Australia, Africa, and Asia. Caldesia parnassifolia is widespread across Europe, Asia, Africa, and Queensland.

Reader's Guide

Caldesia holds significance primarily through its extensive fossil record, spanning the Oligocene through Pleistocene epochs in Eurasia, with additional fossil occurrences in Idaho and Vermont, United States. Ten fossil species have been described, indicating a once broader distribution and diversity. The three living species continue to inhabit regions across Europe, Asia, Africa, and Australia, reflecting the genus's long evolutionary history. The genus was named after the Italian botanist and politician Ludovico Caldesi and was formally described by Filippo Parlatore in 1860. Its morphological features—such as basal leaves, hermaphrodite flowers with 6 to 11 stamens, and drupaceous fruitlets with woody endocarp and spongy exocarp—distinguish it among aquatic plants. The presence of varieties within Caldesia oligococca, including those with spiny or tubercled fruitlets, suggests ecological or regional adaptations. The genus's legacy lies in its contribution to understanding aquatic plant evolution and biogeography, as evidenced by its fossil and modern distributions.

Did You Know?

• The genus Caldesia includes three living species and ten fossil species.
• Its fossil record extends from the Oligocene through the Pleistocene in Eurasia and also includes finds in Idaho and Vermont.
• The genus was named after Italian politician and botanist Ludovico Caldesi (1821–1884).