Included here is the Juan Fernandez Islands, which mainly comprises Alejandro Selkirk (Masafuera), Robin Crusoe (Masatierra), Santa Clara and the Desventuradas Islands (San Ambrosio and San Felix).

Fernandezian Lower Montane Forest

These forests of Juan Fernandez have a similarity to the laurineous forests of Macronesia and the Metrosideros forests of the Hawaii, but also have many elements linking them to the Valdivian rainforests of Chile. Unlike these mainland forests, however, both Nothofagus (southern beech) and woody climbers are absent. Structurally they can be divided into four layers – an upper canopy (with certain trees reaching heights of 30 m or so), a sub canopy above 6 m, a shrub layer of roughly between 2 - 6 m, a field layer of between 0.2 and 2m, and a ground layer of under 0.2 m (mostly formed of cryptogams). On Masatierra the upper canopy mainly comprises the two endemic species Fagara mayu (Rutaceae) and Nothmyrica fernandeziana (Myricaceae), while the lower canopy includes Drymys confertifolia and the endemic Boehmeria excelsa (Urticaceae), Coprosma pyrifolia (Rubiaceae), Juania australis (Arecaceae), Rhaphithamnus venustus (Verbenaceae) and Sophora fernandeziana (Fabaceae). The endemic sandalwood Santalum fernandezianum (Santalaceae) was also thought to have been abundant in bygone years but now appears to be extinct.  The shrub layer is also mainly populated by endemic species such as Rea micrantha, Symphochaeta macrocephala (Asteraceae) and Gunnera peltata (Gunneraceae). The latter is, in fact, the largest herb on the island occasionally reaching heights of 5 m. Also important within the shrub layer is the magnificent endemic fern Thyrsopteris elegans (Thyrsopteridaceae) with fronds well over the height of a man. Among the larger field layer species are various endemic dwarf shrubs such as Halorrhagis masatierrana (Halorrhagidaceae) and Wahlenbergia larrainii (Campanulaceae), the endemic graminoids Bromus fernandezianus (Poaceae), Carex berteroniana and Uncinia douglasii (Cyperaceae), and a rich collection of endemic ferns including Aspenium stellatum (Aspleniaceae), Blechnum cycadifolium (Blechnaceae), Dicksonia berteroana, Dryopteris inaequalifolia (Dryopteridaceae), Polystichum berterianum (Dryopteridaceae) and Pteris berteroana (Pteridaceae). Three of these, Blechnum cycadifolium, Dryopteris inaequalifolia Dicksonia berteroana, are tree ferns, although the first two species rarely reach heights of more than a metre. Dicksonia, on the other hand, has on occasion measured up to 6 m. Ground layer species are mainly bryophytes such as Isopterygium fernandezianum and Lophocolea fernandeziensis. Bryophytes together with lichens also form the bulk of the rich epiphytic flora, while the few vascular epiphytes include the endemic Peperomia fernandeziana (Piperaceae) and the endemic fern Polypodium intermedium (Polypodiaceae). On Masafuera, the lowland forests have a slightly different species composition. Among the upper canopy trees, Nothomyrica fernandeziana is replaced by the endemic Myrceugenia schulzei (Myrtaceae), and Fagara mayu is replaced by the smaller endemic Fagara externa (Rutaceae). In the undergrowth, Gunnera peltata is replaced by the smaller endemic Gunnera masafuerae (Gunneraceae) and Halorrhagis masatierrana is replaced by the endemic Halorrhagis asperrima (Halorrhagidaceae). Other differences include the presence of the endemic herbaceous species Solanum masafueranum (Solanaceae) and the endemic fern Blechnum longicauda in the field layer, and a more frequent presence of the miniature endemic tree Urtica fernandeziana (Urticaceae).

Fernandezian Upper Montane Forest

Above an altitude of about 500 m the forests gradually take on a different character. On Masatierra these upland forests extent to the highest parts of the island including the summit of El Yungue the highest peak at 927 m. Masafuera, on the other hand, reaches a sufficient height, about 1500 m, to give rise to a climatic timber-line. Nevertheless, the remaining montane forests are still better developed on Masatierra. Frequent fogs characterize the zone, and the forests differ from lowland areas by an increasing frequency of ferns, particularly the endemic tree fern Dickinsonia berteroana (Dickinsoniaceae). In fact, these upland forests have been described as fern forest.  From a structural point of view, the same layering occurs as in the lowland forests with an upper and lower canopy, shrub, field and ground layer. Characteristic upper canopy trees include several endemic species including Azara fernandeziana (Flacourtiaceae), Dickinsonia berteroana, together with Nothomyricia fernandeziana and several other species commonly encountered in lowland forest. The lower canopy also includes many lowland species, but among the shrub layer are several endemics more or less confined to the montane zone. These include Cuminia fernandeziana (Lamiaceae), Lactoris fernandeziana (Lactoridaceae), Ugni selkirkii (Myrtaceae) and Wahlenbergia grahamae (Campanulaceae). An interesting feature of Juan Fernandeziana is the large number of small rosette trees that have evolved. Altogether there are 25 species 9 of which are endemic and several of these belong to endemic genera. In the uplands these include Centaurodendron dracaenoides (Asteraceae), various species of Dendroseris, Phoenicoseris pinnata (Asteraceae) and Yunquea tenzii (Asteraceae). The latter species is confined to the summit of El Yunque. All these particular taxa belong the family Asteraceae, but this life form has evolved in four different families. The moist conditions of these forests have allowed a rich epiphytic flora to develop. For example, Rhetinodendron berterii is often an epiphyte on other larger species such as Dickinsonia. Epiphytic ferns are particularly well represented and include several endemic filmy-ferns such Serpyllopsis caespetosa var. fernandeziana (Hymenophyllaceae), Trichomanes philippianum (Hymenophyllaceae) and the distinctive bronze-green Hymenophyllum rugosum (Hymenophyllaceae). Ferns and bryophytes also mainly populate the field layer. The few herbaceous vascular plants include the two endemic species Dysopsis hirsuta (Euphorbiaceae) and Peperomia berteroana (Piperaceae) both of which are not uncommon in the wetter, shady areas.  

References

Crawford, D. J., Sang, T.,  Stuessy, T. F., Kim, S. & Silvao, M 1998. Dendroseris (Asteraceae: Lactuceae) and Robinsonia (Asteraceae: Senecioneae) on the Juan Fernandez Islands: similarities and differences in biology and phylogeny.  In: Evolution and Speciation of Island Plants. Eds. T. S. Stuessy and M. Ono. Cambridge University Press.

Dirnbock, T., Greimler, J., Lopez, P. & Stuessy, T. F. 2003. Predicting future threats to the native vegetation of Robinson Crusoe Island, Juan Fernandez Archipelago, Chile. Conservation Biology, 17: 1650-1659.

Mueller-Dombois, D. & Fosberg, F. R. 1998. Vegetation of the Tropical Pacific Islands. Springer.

Skottsberg, C. 1920-1953. The natural history of Juan Fernandez and Easter Island. Volume II. Botany. Almqvist and Wiksells Bokteyckeri, Upsala.

Stuessy, T. F., Crawford, D. J. Marticorena, C. & Rodriguez, R. 1998. Island biogeography of angiosperms of the Juan Fernandez archipelago.  In: Evolution and Speciation of Island Plants. Eds. T. S. Stuessy and M. Ono. Cambridge University Press.

Stuessy, T. F., Crawford, D. J. Marticorena, C. & Silvao, M 1998. Isolating mechanisms and modes of speciation in endemic angiosperms of the Juan Fernandez Islands.  In: Evolution and Speciation of Island Plants. Eds. T. S. Stuessy and M. Ono. Cambridge University Press.

Stuessy, T. F., Marticorena, C., Rodriguez, R. R., Crawford, D. J. & Silva, M. O. 1998. Endemism in the vascular flora of the Juan Fernandez Islands. Aliso, 13: 297-307.

Stuessy, T. F., Sanders, R. W. & Silva, M. 1984. Phytogeography and evolution of the flora of the Juan Fernandez Islands. In: Biogeography of the Tropical Pacific (Proceedings of a Symposium). Eds. F. J. Radovsky, P. H. Raven and H. Sohmer. Bishop Museum Special Publication No. 72.

Stuessy, T. F., Swenson, U., Crawford, D. J., Anderson, G. & Silva, M. O. 1998. Plant conservation in the Juan Fernandez Archipelago, Chile. Aliso, 16: 89-101.