Included here is a series of subantarctic islands comprising the Kerguelen Islands, Marion Island, Prince Edward Islands, Crozet Islands, Heard Islands, McDonald Island, Saint Paul Island and Amsterdam Island.

Kerguelenian Acaena magellanica wetlands

Wetland vegetation characterized by Acaena magellanica typically forms along riverbanks and in springs and flushes. The few other vascular plants found here include Agrostis magellanica and the endemic Pringlea antiscorbutica (Brassicaceae), and these are often outnumbered by bryophytes. Typical species are Brachythecium subplicatum, Breutelia integrifolia, Drepanocladus uncinatus, Philonotis angustifolia, and several have bi-polar or cosmopolitan distrubutions, although the latter is endemic. Communities dominated by Acaena magellanica are recorded from most sub Antarctic islands, and in fact, on Kerguelen and Crozet, it forms the dominant vegetation over large parts of the lowlands.

Kerguelenian Juncus scheuchzerioides oligotrophic mire

Wherever drainage is impeded, the cool hyper-oceanic climate of these islands favours the formation of peat and extensive areas have developed on some islands. However, Sphagnum species, which form the foundation of important bog communities throughout much of World, are absent, and do not play a significant role in the mire vegetation of any of sub Antarctic islands. Juncus scheuchzerioides is the most conspicuous species of these mires, but despite this, bryophytes are still the most important peat-forming plants, and the role of Sphagnum has been largely replaced by species such as Blepharidophyllum densifolium, Breutelia integrifolium, Drepanocladus uncinatus, Jamesoniella colorata and Racomitrium lanuginosum. Few other vascular plants are found in these mires although Lycopodium magellanicum is more or less confined to them. They do, however, provide habitat for a large number of other bryophytes including several endemic species such as Andrewsianthus marionensis, Jungermannia coniflora, Metzgeria marionensis, Plagiochila crozetensis, Ptychomnium ringianum and Symphyogyna marionensis.

References

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Wace, N. M. 1965. Vascular Plants. In: Biogeography and Ecology in Antarctica. Eds. Mieghem, J. Van, Oye, P. Van and Schell, J. Dr Junk Publishers. The Hague.