Giliastrum is a small genus of flowering plants in the family Polemoniaceae (the phlox family), placed within the order Ericales. The genus comprises roughly ten accepted species of herbaceous to somewhat shrubby plants native to arid and semi-arid regions of the Americas. The genus was first formally described in 1917 in Flora of the Rocky Mountains, and its name commemorates Filippo Luigi Gilii (1756–1821), an Italian clergyman, naturalist, and astronomer associated with the Vatican.
Members of Giliastrum share the characteristic features of the Polemoniaceae: flowers with five fused petals forming a tube or funnel, five stamens, and a three-lobed stigma. The plants tend to grow in open, dry habitats across a wide latitudinal range, from the southwestern United States south through Mexico and the Caribbean to northwestern Argentina. Species such as Giliastrum acerosum, G. incisum, and G. rigidulum represent the range of form within the genus, from needle-leaved to incised-leaved variants adapted to rocky and xeric soils.
Etymology
The genus name Giliastrum honours Filippo Luigi Gilii (1756–1821), an Italian clergyman, naturalist, and astronomer who worked in part at the Vatican City. The genus was first described and published in Flora of the Rocky Mountains (1917), page 699.
Distribution
Giliastrum is native to the central and southwestern United States — including Arizona, Colorado, Kansas, New Mexico, Oklahoma, and Texas — as well as Mexico, the Caribbean island of Hispaniola (Dominican Republic), and south to northwestern Argentina.
Taxonomy Notes
Giliastrum belongs to the family Polemoniaceae and the order Ericales. GBIF recognises the genus as accepted with 11 descendant taxa. The genus was segregated from the broader Gilia complex and formally established in 1917; authorship details are not recorded in the current GBIF entry.
