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| Kahakuloa operculispora A.V.Freire, Judz., Cargill, L.L.Forrest & Gradst., Freire, Judziewicz, Cargill, Forrest, Gradstein, Oppenheimer, Pezzillo et Sepsenwol, 2023. DOI: 10.11646/bde.46.1.4 |
Abstract
Kahakuloa operculispora, a new simple thalloid liverwort endemic to Hawaiʻi, so far only known from high elevation bogs in western Maui, is described and illustrated. The thallus has prominent reddish-purple rhizoids, uniseriate ventral slime papillae and lacks scales. The plants are dioicous; male plants have antheridia sunken in several rows of dorsal chambers, subtended by scales, while female plants have clustered archegonia enclosed by thick, barrel-shaped involucres that develop serially at the plant apex, before fertilization, and are arranged in a single dorsal row at maturity; perichaetial scales and pseudoperianths (defined as involucres developing after fertilization) are lacking. The capsules are spherical, 2−3 stratose, and dehisce irregularly; the spores are areolate and have a unique operculum-like disk on the proximal face. Molecular and morphological evidence supports placement of the plant in a new genus and family in the order Fossombroniales, suborder Fossombroniineae. Kahakuloa is the first liverwort genus endemic to Hawaiʻi, and Kahakuloaceae is the only known endemic Hawaiian land plant family.
Keywords: Marchantiophyta, Kahakuloa, Hawaii, Fossombroniineae, liverwort
Kahakuloaceae A.V.Freire, Judz., Cargill, L.L.Forrest & Gradst., new family
Kahakuloa operculispora A.V.Freire, Judz., Cargill, L.L.Forrest & Gradst. new genus and species
Diagnosis:—Kahakuloa operculispora differs from all other members of Fossombroniales in having numerous, apically developing (pre-fertilization), inflated, barrel-shaped involucres, each protecting a small cluster of archegonia; in having sunken antheridia in several rows of dorsal chambers protected by scales; and in having spores with aproximal operculum-like disk. The genus is morphologically most similar to Allisonia in its lack of ventral scales, presence of long, reddish-purple rhizoids, and ventral hairs tipped with slime papillae; however, Allisonia differs in having archegonia in a single cluster enclosed by partially connate scales, by having superficial antheridia, by having a true calyptra rather than a shoot calyptra; and by having cristate rather than areolate spores that lack an operculum-like disk.
A. Virginia Freire, Emmet J. Judziewicz, D. Christine Cargill, Laura L. Forrest, S. Robbert Gradstein, Hank L. Oppenheimer, Zachary Pezzillo and Sol Sepsenwol. 2023. Kahakuloa operculispora, A New Hawaiian Simple Thalloid Liverwort in A New Genus and Family, Kahakuloaceae (Fossombroniales). Bryophyte Diversity and Evolution. 46(1); 10-34. DOI: 10.11646/bde.46.1.4