Description of five new species of the Madagascan flagship plant genus Ravenala (Strelitziaceae)

Thomas Haevermans,Jacqueline Razanatsoa,Agathe Haevermans,Vololoniaina Jeannoda,Patrick Blanc,Claude-Marcel Hladik,Annette Hladik

doi:10.1038/s41598-021-01161-1

Abstract

Madagascar’s emblematic traveller’s tree is a monospecific genus within Strelitziaceae, the family of the South African bird of paradise. Until now, this endemic genus consisted of a single species: Ravenala madagascariensis Sonn., which is grown everywhere in the tropics as an ornamental plant. The plant is immediately recognizable for its huge fan-forming banana-like leaves and is locally referred to in Magagascar by several vernacular names. “Variants” have been mentioned in the literature, but without any attempt to recognize formal taxa based on diagnostic features. In this paper, we formally describe five new species and fix the application of the name R. madagascariensis to the populations growing on the eastern coast of Madagascar, with the epitype growing in the marshy Fort-Dauphin area in the south. This paper has numerous implications for conservation biology and other domains of life sciences, due to the importance of this genus for the conservation of Madagascan ecosystems, the ornamental plant trade, as well as for its invasive status in several tropical areas.

Highlights

Madagascar’s emblematic traveller’s tree is a monospecific genus within Strelitziaceae, the family of the South African bird of paradise
Our own field and herbarium specimen observations of the various morphotypes led us to recognize and distinguish six stable units defined by observable characteristics, consisting of five new species in addition to Ravenala madagascariensis
The five new species described in this paper can be identified at both young and adult stages from distinctive morphological characters defined from petiole sheath margins, petiole coloring and morphology, suckering or solitary habits and flower and fruit traits

Summary

Introduction

Madagascar’s emblematic traveller’s tree is a monospecific genus within Strelitziaceae, the family of the South African bird of paradise. Until now, this endemic genus consisted of a single species: Ravenala madagascariensis Sonn., which is grown everywhere in the tropics as an ornamental plant. Ravenala seeds are attached to a fatty aril which has a distinctive bright ultramarine blue color (varying from deep ultramarine blue to sky blue depending on the maturity), which contrasts with the orange aril found in the other genera of Strelitziaceae (the South American endemic Phenakospermum and the South African Strelitzia). One of the differences highlighted is the seemingly variable suckering ability of Ravenala This genus is usually represented as a tall suckering plant with leaves forming a perfect fan, and this can be appreciated from the many cultivated specimens throughout the world. Solitary (non-suckering) Ravenala taxa are another exception in presenting a monocaulous monopodial architecture (Corner model19) within a suckering order (Tomlinson m odel[19])

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