Nymphaea thermarum

Common Name: Pygmy Rwandan Water Lily

Family: Nymphaeaceae

Country of Origin: Rwanda

Habitat: mud flats below thermal hot springs (now defunct)

Description: A tiny waterlily, forming rosettes 10-20 cm wide and comprising bright green lily pads (laminas) with short petioles. The lily pads can be as little as 1 cm in diameter. The central growing tip sinks in the wet mud, preventing the developing pads from drying out before unfurling.²

It was known from just one location in Mashyuza, in southwest Rwanda, but it disappeared from there around 2012 due to over-exploitation of the hot spring that fed this fragile habitat. Water was prevented from reaching the surface, resulting in the desiccation of the few square meters where this species grew, and no plant at the original location is known to have survived in the wild. ² In 2024, Michael Thomas of the National Herbarium of Rwanda reported that there are some surviving populations in the vicinity of the original site, and that the Hot Spring Waterlily is not truly extinct in the wild (personal communication with Matthew Opel).

USDA Zone: 10

Accession #: 201400265

Accession Date: 2014-12-18 00:00:00

Confirmed At: 2026-03-10 19:18:39

Bloom Status: 🪴 Not Flowering

Location: 1106

Quantity: 7

Source: Brian Leib - Harvard Weld Hill GH

Provenance:

Collector: E. Fischer 3034, 09.10.1993

Collection: R[w]anda, Pref. Cyangugu, called Quelle Mashyuza by the Nyakabuye.

Altitude: 1000 m

Culture: Culture in fine loam, with water level equal to soil level - roots submersed, leaves emergent. Bright light, tropical temps. Prone to western flower thrips. Repot every 6 months or so.

Division: Magnoliophyta

Class: Magnoliopsida

Subclass: basal angiosperms

Order: Nymphaeales

Family: Nymphaeaceae