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Type: Article
Published: 2023-12-29
Page range: 10-34
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Kahakuloa operculispora, a new Hawaiian simple thalloid liverwort in a new genus and family, Kahakuloaceae (Fossombroniales)

Biology Department, Chemistry Biology Building, University of Wisconsin, Stevens Point, WI 54481-3897, USA, Herbarium Pacificum, Bernice Pauahi Bishop Museum, 1525 Bernice Street, Honolulu, HI, 96817, USA
Biology Department, Chemistry Biology Building, University of Wisconsin, Stevens Point, WI 54481-3897, USA, Herbarium Pacificum, Bernice Pauahi Bishop Museum, 1525 Bernice Street, Honolulu, HI, 96817, USA
Australian National Herbarium CANB, Centre for Australian National Biodiversity Research (a joint venture between Parks Australia and CSIRO). GPO Box 1777, Canberra, ACT. Australia 2601
Royal Botanic Garden, 20A Inverleith Row, Edinburgh, EH3 5LR, Scotland
Meise Botanic Garden, 1860 Meise, Belgium
Plant Extinction Prevention Program, Pacific Cooperative Studies Unit, University of Hawaiʻi, P.O. Box 909, Makawao, Hawaiʻi, 96768, USA
Plant Extinction Prevention Program, Pacific Cooperative Studies Unit, University of Hawaiʻi, P.O. Box 909, Makawao, Hawaiʻi, 96768, USA
Biology Department, Chemistry Biology Building, University of Wisconsin, Stevens Point, WI 54481-3897, USA
Hawaiʻi Kahakuloa liverwort Marchantiophyta Fossombroniineae


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.


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