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tasmanian mosses - mniaceae

pohlia species

The family is represented in Tasmania by 2 genera comprising of 6 species. We identified to species level by the 'vermicular' nature of the gemmae from Shaw's paper cited below.

What struck us as interesting about this species is the profusion of gemmae found growing in the leaf axils, this particular form being known as '(vermicular) bulbils'. Gemmae are asexual propagules capable of developing into clonal replicas of the parent and complement sexual reproduction through spore production. However they are delicate and more likely to establish close to the parent plants. Spores are much hardier and likely to colonize further.

Pohlia flexuosa
1. Plants growing on road bank

 

upper leaves
2. upper leaves
bulbils on leaf
3. bulbils on leaf
single bulbil
4. single bulbil
leaf cells
5. leaf cells

 

Pix 2: shows quantities of gemmae lodged in the leaf axils of the moss; this was from our first collection where the bulbils dispersed upon wetting
Pix 3: a single leaf excised from the stem exposing the adhering bulbils; these are from a second collection, presumably less mature than those in previous pix and remained attached despite wetting
Pix 4: a single bulbil
Pix 5: cell shape is often useful for identification

Capsules are often a good diagnostic feature for identification but Shaw quotes J. Spence having noted that all Tasmanian specimens examined were sterile. In which case all multiplication would be exclusively by gemmae.

References
Shaw, A.J., 'A revision of the Moss Genus Pohlia Hedw. (Mniaceae) in Australia', Systematic Botany (2006), 31(2): pp.247-257

Web
- Glime, J., 'Ecophysiology of Development: Brood Bodies' Chapter 5-7 of Bryophyte Ecology
- Guerra, J., 'Pohlia Section (Mielichhoferiaceae, Bryophyta) with axillary bulbils in the Iberian Peninsula', 2007 has detailed images of other Pohlia bulbils
- Shaw, J. & Fife, A.J., 'Pohlia australis sp. nov. (Musci) from New Zealand with notes on some other austral Pohlias' (originally published in New Zealand Journal of Botany, 1985, Vol 23: 183-186) is available from the Smithsonian Digital Repository

Page URL: http://www.bluetier.org/Moss/mniaceae.htm

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