Close observation of a common fern challenges long-held notions of how plants move. A commentary on 'Fern fronds that move like pine cones: humidity-driven motion of fertile leaflets governs the timing of spore dispersal in a widespread fern species'

Abstract

This article comments on:

Jacob S. Suissa, Fern fronds that move like pine cones: humidity-driven motion of fertile leaflets governs the timing of spore dispersal in a widespread fern species, Annals of Botany, Volume 129, Issue 5, 11 April 2022, Pages 519–527 https://doi.org/10.1093/aob/mcab137

Keywords: Fern fronds; Onocleaceae; species distributions.

Fig. 1.

All known temperate species of the Onocleaceae make overwintering fertile fronds. For example, the temperate Pentarhizidium orientalis, an Old World native, produces fertile fronds in the summer (A) that overwinter (B) and probably release spores the following spring. A similar pattern occurs in the New World temperate Matteuccia struthiopteris (C and D). It is probable that these species use similar patterns of humidity-driven movement to release their spores. Fertile–sterile dimorphism is common in ferns, but it is unlikely that such movement is employed by all such taxa. For example, taxa in (E) Elaphoglossum and (F) Lomariopsis produce achrostichoid sori with sporangia openly exposed, with no evidence of pinnae movement. Photo courtesy of (A) D. Chimitov, (B) O. Diras and (C) R. Moran.