Oreostylidium
Oreostylidium | |
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Diagram from Mildbraed's monograph of Stylidiaceae in 1908 | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Asterids |
Order: | Asterales |
Family: | Stylidiaceae |
Subfamily: | Stylidioideae
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Genus: | Oreostylidium Berggr. 1878 |
Species: | O. subulatum
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Binomial name | |
Oreostylidium subulatum Berggr. | |
Synonyms | |
Stylidium subulatum Hook. 1864 |
Oreostylidium is a
Characteristics
Oreostylidium subulatum is a very small, cæspitose, and densely tufted plant about 2–3 cm tall. The 2 cm long linear-subulate leaves form a basal
![](http://upload.wikimedia.org/wikipedia/en/thumb/9/9d/Oreostylidium_and_S_turbinatum.jpg/230px-Oreostylidium_and_S_turbinatum.jpg)
The flower
Distribution
Oreostylidium subulatum is endemic to
Botanical history and taxonomy
Oreostylidium subulatum was originally described by Sir William Jackson Hooker in 1864 as Stylidium subulatum in the related genus Stylidium. Hooker based his classification on imperfect floral specimens and thus had to rely upon fruit morphology and habitat similarities. Working from the fruit morphology alone, Hooker noticed his specimen resembled several members of Stylidium subgenus Tolypangium. In 1878, Ferdinand von Mueller proposed that what was known then as Stylidium subulatum be included within the related genus Phyllachne based on flower morphology. In the same year, Sven Berggren proposed the move that created the most accepted classification within the genus he created, Oreostylidium.[2]
Then in 1887, William Colenso described what he thought was a new species, Oreostylidium affine, based on specific morphological differences from previous descriptions of O. subulatum. He noted that he was rather unsure of the specific classification of this new species:
- "This plant resembles Oreostylidium subulatum, Berggren, as carefully drawn by him; (which is also the "Stylidium? subulatum, n. sp.," of Hook. f., as given by him with doubt, from his imperfect specimens, in the "Handbook N.Z. Flora," p. 168;) and it would be by me referred to that species were it not for its differential characters."[1]
Colenso also admitted in his description of O. affine that the location data for both O. affine and O. subulatum were very similar and at least one morphological detail of his plant specimens was damaged, which could have effected his analysis.[1] O. affine was later placed under O. subulatum as a synonym.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Stylidium_graminifolium_flower_spike.jpg/220px-Stylidium_graminifolium_flower_spike.jpg)
Oreostylidium remained relatively untouched after that until an extensive review of the morphological details of Stylidiaceae was combined with genetic analysis of the chloroplast DNA genes rbcL and ndhF in 1998. The result of this study revealed that all major cladistic trees generated from the data suggested that the genus Oreostylidium is nested within the genus Stylidium. Based on that data, the authors of that study proposed that O. subulatum be known once again under its very first name, Stylidium subulatum and Oreostylidium should be reduced to synonymy of Stylidium.[2] In 2002, another study based on molecular evidence determined that in the most parsimonious cladistic tree, Stylidium graminifolium and O. subulatum were closely related, with O. subulatum again nested within Stylidium. Based on molecular clock calculations and their data, the researchers concluded that S. graminifolium and O. subulatum shared a common ancestor about 3 million years ago. The researchers responsible for the 2002 study also concluded that Oreostylidium should be transferred to Stylidium and O. subulatum should retake its former name as Stylidium subulatum.[3]
References
- ^ a b c d Colenso, W. (1887). Art. XXVII.—On new Phœnogamic Plants of New Zealand. Read before the Hawke's Bay Philosophical Institute, 12 September 1887. Transactions and Proceedings of the Royal Society of New Zealand, 20: 197.
- ^ a b c Laurent, N., Bremer, B., and Bremer, K. (1999). Phylogeny and generic interrelationships of the Stylidiaceae (Asterales), with a possible extreme case of floral paedomorphosis. Systematic Botany, 23(3): 289-304.
- ^ a b c Wagstaff, S.J. and Wege, J. (2002). Patterns of diversification in New Zealand Stylidiaceae. American Journal of Botany, 89(5): 865-874.
- ^ Good, R. (1925). On the geographical distribution of the Stylidiaceae. New Phytologist, 24(4): 225-240.
- ^ a b Buchanan, J. (1879). Art. LVI.—Notes on New Zealand Plants. Read before the Wellington Philosophical Society, 21 February 1880. Transactions and Proceedings of the Royal Society of New Zealand, 12: 380.