Pterygopappus
| Pterygopappus | |
|---|---|
| |
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Asterales |
| Family: | Asteraceae |
| Subfamily: | Asteroideae |
| Tribe: | Gnaphalieae |
| Genus: | Pterygopappus Hook.f. |
| Species: | P. lawrencii
|
| Binomial name | |
| Pterygopappus lawrencii | |
| Synonyms | |
| |
Pterygopappus is a genus of flowering plants in the tribe Gnaphalieae within the family Asteraceae.[1][2] There is only one known species, Pterygopappus lawrencii (sage cushion plant), which is endemic to alpine Tasmania. It forms thick, light blue/green mats with densely packed leaves. It is most common in the mountains of the northeastern part of the island. It is a slow grower and prefers cool, moist environments.[3][4][5][6]
Description
[edit]Pterygopappus lawrencii has a noticeably tufted habit and is easily identified by its sage-green leaves[7] which are no more than 5 mm long. These leaves are tightly congested[8] and can be said to resemble a small cabbage or rose. They are covered in very fine, small and white hairs.[9] Beneath the tightly grouped sets of leaves, stems elongate at a rate which is equal to the rate at which new leaves are produced.[8] It is therefore difficult to identify which leaves are connected to which stem.[8] This is the main method for how this species spreads across the alpine landscape.[8] From the centre of the small ‘rosette’ emerges a white, small daisy like flower between December- March.[8] The fruit of this species is an achene.[9]
Habitat and distribution
[edit]Pterygopappus lawrencii is found in montane heathlands, alpine vegetation areas and wet screes.[9] It is distributed mostly across the east of Tasmania especially in the Central Plateau areas[9] of Mount Field National Park and Cradle Mountain National Park. The habitat of the species displays the hardiness of the plant. It is ideally found in areas with a thin and peaty soil, the product of heavily eroded dolerite and siliceous bedrock, where most of the soil has been removed by glacial processes.[10] It is also constantly exposed to high winds, snow and low temperatures[10] It is unusual to find an area of P. lawrencii growing as a monoculture as they most often occur within a mosaic of other cushion plant species such as Donatia novae-zelandiae, Dracophyllum minimum, Abrotanella forsteroides and Schizacme archeri.[7] This ability to grow extremely close and integrate with other cushion plant species is part of the reason for their success in these trying conditions. The tightly packed leaves enable a reasonably constant temperature to be maintained at the core of the plant,[8] and their low and spreading nature enables them to miss the worst of the wind sweep.
Ecological importance
[edit]The species can be described as an engineering or foundation species, due to its ability to create tarns and small rivers in alpine areas.[10] Collectively, cushion plants promote species richness. They have been found to attract a greater diversity of species in alpine areas compared to non-cushion plants, provide both refuge for arthropods as well as a pollination resource for insects.[11]
Threats
[edit]One of the major threats to alpine vegetation is fire, although this is a species which is able to recover from fire reasonably well.[10] However, foot traffic from bushwalkers greatly damages these plants, especially in very wet or waterlogged areas.[12] Damaged plants may take up to 10 years to fully recover, in which time erosion is increased due to lack of soil stability created by these plants.[13] Insects and arthropods which depend upon these species for food and refuge may also decrease in these areas.
References
[edit]- ^ Hooker, Joseph Dalton. 1874. London Journal of Botany 6: 120-121 in Latin
- ^ "Name - Pterygopappus Hook. f". Tropicos. Retrieved 2017-03-26.
- ^ "Key to Tasmanian Dicots". Utas.edu.au. Retrieved 2017-03-26.
- ^ Flann, C (ed) 2009+ Global Compositae Checklist Archived 2015-01-03 at archive.today
- ^ "Pterygopappus lawrencei Hook.f. — The Plant List". Theplantlist.org. 2012-02-11. Retrieved 2017-03-26.
- ^ "Pterygopappus | Atlas of Living Australia". Bie.ala.org.au. Retrieved 2017-03-26.
- ^ a b "Key to Tasmanian Dicots". Utas.edu.au. Retrieved 2017-03-26.
- ^ a b c d e f R. D. Coghlan. "Cushion Plants". Apstas.com. Retrieved 2017-03-26.
- ^ a b c d "Family Index". Understorey-network.org.au. Retrieved 2017-03-26.
- ^ a b c d "Parks & Wildlife Service - Communities". Parks.tas.gov.au. 2008-07-11. Retrieved 2017-03-26.
- ^ Reid, Anya M.; Lortie, Christopher J. (November 2012). "Cushion plants are foundation species with positive effects extending to higher trophic levels". Ecosphere. 3 (11): 1–18. Bibcode:2012Ecosp...3...96R. doi:10.1890/ES12-00106.1.
- ^ Kitchener, A.; Harris, S., eds. (2013). From Forest to Fjaeldmark: Descriptions of Tasmania's Vegetation (PDF) (2 ed.). Department of Primary Industries, Parks, Water and Environment.
- ^ "Parks & Wildlife Service - Alpine and Subalpine Plants of Tasmania". Parks.tas.gov.au. 2009-06-01. Retrieved 2017-03-26.