Cololejeunea macounii

Cololejeunea macounii
Phylum: Marchantiophyta
Family: Lejeuneaceae
Genus: Cololejeunea
Common NameNone "Colo"
Quick & Dirty IDLittle yellow peanuts
© Daniel Tucker
iNaturalist
© John Reynolds
iNaturalist

Distinguishing Features

C. macounii is a tiny <0.9mm wide, epiphytic leafy liverwort that grows exclusively in extremely humid coastal rainforests. C. macounii can be recognized by its oblong leaf lobes, leaf cells with large papillae, and by its toothed lobule margin. Previously thought to be rare, before 2023 was only known from five or six locations. Since 2023 recent surveys uncovered new records of the species on the Central Coast and Vancouver Island. It is likely C. macounii is more common than previously thought but has remained elusive due to its extremely small size and specific habitat requirements.

Similar species

Cololejeunea macounii is most commonly confused with Radula bolanderi or other species of Radula which are similar sized and also grow as epiphytes. Microscopically Cololejeunea can be easily disinguished by all species of Radula by its toothed apical lobule margin, and large leaf cell papillae. In the field, Radula bolanderi is often found growing in the same habitat as Cololejeunea, but the latter can be recognized by the more oblong leaf lobes and pale yellowish green colour, compared to the rounder leaves and fresher green colour of R. bolanderi. As well, the leaf arrangment of C. macounii is more disorganized compared to R. bolanderi which often has leaves cleanly alternating.

Habitat

Consitently humid microsites in hypermaritime rainforests. Often found growing on Ribes sp. Rubus spectabilis, or Oplopanax horridus stems along streams or in spray zones. Ocasionally found as an epiphyll on Tsuga or Abies needles, or on Alnus rubra logs.

Associated species

Radula bolanderi, Metzgeria temperata, Ulota spp.

Distribution Map

Relevant Literature