Morphological and Genetic Diversities of Habenaria radiata (Orchidaceae) in the Kinki Area, Japan

Abstract

Floral organs have evolved from leaves for reproduction, and the morphological analyses help to understand the plant diversity and evolution. Habenaria radiata (syn. Pecteilis radiata) is a terrestrial orchid living in wetlands in Japan, Russia, South Korea, and China. The habitats of this plant in Japan have been reduced because of environmental destruction and overexploitation, and thus it is on the Red List of Japan as a Near Threatened species. One of the three petals of the H. radiata flower is called a lip or labellum, which resembles a flying white bird, egret, or white heron, with its proposed function being to attract pollinators. To understand the diversity of H. radiata plants in different areas, we examined the lip morphology and phylogeny of populations from eight habitats in the Kinki area, Japan. The complex shapes of the lips were quantified and presented as a radar chart, enabling characterization of the morphological difference among populations. Phylogenetic analysis with microsatellite markers that we generated showed the variation of genetic diversity among populations, suggesting the different degrees of inbreeding, outbreeding, and vegetative propagation. Our approach offers a basic method to characterize the morphological and genetic diversity in natural populations.

Specialized petal with conspicuously fringed margin influences reproductive success in Habenaria radiata (Orchidaceae)

“…For instance, the common name for Habenaria radiata —the white egret orchid—is derived from its exquisite lip that resembles the graceful flight of a white egret. The lip has three lobes, with two side lobes extending laterally that are highly fringed and have a characteristic plume‐like or winglike shape, whereas the central lobe lacks ornamented margins (Figure 1a,b; Tachibana et al, 2021). According to legend, the spectacular floral morphology was born of the soul of an exhausted egret (Kimura, 1982).…”

Genetic Diversity on a Rare Terrestrial Orchid, Habenaria linearifolia in South Korea: Implications for Conservation Offered by Genome-Wide Single Nucleotide Polymorphisms

“…The proportion of threatened taxa in the genus will likely grow over time due to ongoing environmental changes and a lack of knowledge on many Habenaria taxa. Despite the increased vulnerability, there are only a handful of Habenaria taxa for which the population-level diversity pattern has been investigated ( Zhang and Gao, 2017 ; Chung et al, 2018 ; Tachibana et al, 2021 ). Habenaria linearifolia (Maximowicz) Szlachetko, a rare terrestrial orchid with a narrow distribution (South Korea, E China, Japan, and Russian Far East) is restricted to bogs and wet grasslands ( Lee and Choi, 2006 ; Chen and Cribb, 2009 ; Chung et al, 2018 ).…”