Commelina fluviatilis

Lore & Background

Commelina fluviatilis is known from Tanzania, the Democratic Republic of the Congo, Zambia, and the Caprivi Strip region of Namibia. It is one of the most distinctive members of its genus because of its semi-aquatic habitat preference, its floating stems, its long and narrow leaves that are folded in on themselves, and its many-flowered lower cincinnus. The species has tuberous roots set in the soil which allow it to withstand periods of severe drought despite its preference for water. It can grow in over a half meter of water, typically in marshes, swamps, rivers, or lake shores. Like many members of the genus, it cannot self-pollinate, and furthermore has a tendency for its ovules to abort, leading to fruits with few seeds. A phylogenetic study based on the nuclear ribosomal DNA region 5S NTS and the chloroplast region trnL-trnF revealed that Commelina fluviatilis forms a clade with Commelina purpurea and Commelina welwitschii. Both of these relatives are African, share an unusual leaf anatomy, and have linear leaves that are often folded.

Reader's Guide

Commelina fluviatilis is significant as one of the most distinctive members of its genus, primarily due to its semi-aquatic habitat preference and morphological traits such as floating stems, long narrow folded leaves, and a many-flowered lower cincinnus. Its tuberous roots allow it to survive severe drought despite its aquatic preference, and it can grow in over half a meter of water in marshes, swamps, rivers, or lake shores. The species cannot self-pollinate and often produces fruits with few seeds due to ovule abortion. Phylogenetic analysis using nuclear ribosomal DNA (5S NTS) and chloroplast DNA (trnL-trnF) places it in a clade with two other African species, Commelina purpurea and Commelina welwitschii, which share unusual leaf anatomy and linear folded leaves. This genetic relationship underscores its evolutionary context within the genus. The species is documented from Tanzania, the Democratic Republic of the Congo, Zambia, and the Caprivi Strip region of Namibia, highlighting its Central African distribution.

Did You Know?

• Commelina fluviatilis is one of the most distinctive members of its genus due to its semi-aquatic habitat and floating stems.
• It has tuberous roots that allow it to withstand severe drought despite its preference for water.
• A phylogenetic study placed it in a clade with Commelina purpurea and Commelina welwitschii, both African species with unusual leaf anatomy.