Asterella gracilis

Asterella gracilis
Scientific classification
Kingdom:	Plantae
Division:	Marchantiophyta
Class:	Marchantiopsida
Order:	Marchantiales
Family:	Aytoniaceae
Genus:	Asterella
Species:	A. gracilis
Binomial name
	Asterella gracilis; (F. Weber) Underw.

Asterella gracilis is a thallose liverwort in the family Aytoniaceae.

Description

Asterella gracilis has a rigid, dark or light green thallose gametophyte, which can be purple-ish on the margins. The gametophyte is typically 1-2cm long and forked, with the lobes being equal to or less than 1cm long. The upper surface is somewhat bulging, with complex pores and one layer of elongated air chambers; the thallus is thicker in the center. The abaxial surface is purple-ish to black, with scales forming a row on either side of the thickened center. The thickened portion of the thallus has numerous pegged rhizoids. Paroicous, meaning the male and female reproductive organs are beside or near to each other. The archegonial receptacle stalk is around 3cm tall and arises in a notch at the thallus apex; the receptacle is "hemispherical to conic, green to purplish tinged, 3-4 lobed, with conspicuous white membranaceous long-lanceolate pseudoperianth divisions surrounding each hemispherical blade sporangium that opens by an operculum."[1] There are currently no similar species.

Distribution and habitat

A. gracilis is found in Europe, western North America, Alaska, Alberta, BC, Montana, Oregon, Mexico and South America. It is typically found on calcareous substrata, usually on soil found on rock, close to sea level as well as in alpine and subalpine sites.[2]

References

Schofield, Wilf (2017). In Klinkenberg, Brian (ed.). "Asterella gracilis (F. Weber) Underw". E-Flora BC: Electronic Atlas of the Plants of British Columbia, Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. Retrieved 2017-05-15.
Stotler, Raymond; Crandall-Stotler, Barbara (Autumn 1977). "A Checklist of the Liverworts and Hornworts of North America". The Bryologist. 80 (3): 405–428. doi:10.2307/3242017. JSTOR 3242017.

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[1] Schofield, Wilf (2017). In Klinkenberg, Brian (ed.). "Asterella gracilis (F. Weber) Underw". E-Flora BC: Electronic Atlas of the Plants of British Columbia, Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. Retrieved 2017-05-15.

[2] Stotler, Raymond; Crandall-Stotler, Barbara (Autumn 1977). "A Checklist of the Liverworts and Hornworts of North America". The Bryologist. 80 (3): 405–428. doi:10.2307/3242017. JSTOR 3242017.