Stylidium ecorne

Taxobox


image_caption =
status =
status_ref =
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Asterales
familia = Stylidiaceae
genus = "Stylidium"
subgenus = "Centridium"
species = "S. ecorne"
binomial = "Stylidium ecorne"
binomial_authority = (F.Muell. ex F.L.Erickson & J.H.Willis) P.G.Farrell & S.H.James
synonyms ="S. calcaratum" var. "ecorne" :F.Muell. ex F.L.Erickson & J.H.Willis 1956

"Stylidium ecorne" is a dicotyledonous plant that belongs to the genus "Stylidium" (family Stylidiaceae). It is an annual plant that grows from 5 to 12 cm tall. It has pale or bright pink flowers and occurs in swampy areas.

Taxonomy

"S. ecorne" was initially identified by Ferdinand von Mueller, but it was not specifically named until Rica Erickson and Jim Willis reviewed the taxonomy of "Stylidium calcaratum" in 1956 and authored "S. calcaratum" var. "ecorne". Erickson and Willis decided to keep it at the variety level on the basis that it shared a similar morphology to that of "S. calcaratum" with the exception of the nectary spur, which was reduced or absent in "S. calcaratum" var. "ecorne". Pauline G. Farrell and Sydney Herbert James, in their 1979 review, based their decision to elevate the variety to species level on chromosomal and reproductive discontinuities.Farrell, P.G. and James, S.H. (1979). "Stylidium ecorne" (F. Muell. ex Erickson & Willis) comb. et stat. nov. (Stylidiaceae). "Australian Journal of Botany", 27: 39-45.]

Farrell and James discovered that "S. ecorne" has a haploid chromosome number of 13, whereas "S. calcaratum" has a haploid chromosome number of 11. Farrell and James reasoned that dysploid reduction (also called aneuploidy) in the genus "Stylidium" is frequent and probable in this case, meaning that "S. calcaratum" is virtually certain to be derived from "S. ecorne". This reduction is also evident from the floral spur, reduced number of ovules, and increased tolerance of other habitats, which the authors cited as derived conditions in "S. calcaratum". Crosses between "S. ecorne" and "S. calcaratum" yielded very few seeds, indicating that the taxa are well isolated from each other.

Distribution

"S. ecorne" is as widely distributed as "S. calcaratum" but occurs less frequently due to its restricted ecological habitat preference. It can be found from north of Geraldton in Western Australia to Mount Chudalup in the south and east through South Australia to western Victoria with some outlying populations near Gembrook and Violet Town.

See also

* List of "Stylidium" species

References