Asclepias ruthiae
| Asclepias ruthiae | |
|---|---|
 | |
| Asclepias ruthiae in flower | |
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Embryophytes |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Order: | Gentianales |
| Family: | Apocynaceae |
| Genus: | Asclepias |
| Species: | A. ruthiae |
| Binomial name | |
| Asclepias ruthiae Maguire | |
Asclepias ruthiae is a species of flowering plant in the family Apocynaceae. It is endemic to Utah in the western United States, where it grows in desert and shrubland habitats.[1][2]
Taxonomy
The species was first described by botanist Bassett Maguire in 1941 from material collected in the San Rafael Swell of Utah.[3] It has historically been treated as a variety or subspecies of Asclepias uncialis, but is currently accepted as a distinct species.[2]
Description
Asclepias ruthiae is a perennial herb with multiple stems arising from a caudex. The stems are suberect and reach approximately 10–15 cm (3.9–5.9 in) in height. Leaves are broadly ovate, 2.2–4.5 cm (0.87–1.77 in) long, with a pubescent surface and short petioles.[3]
The inflorescences are small, umbel-like clusters bearing 2–7 flowers. The flowers have a pale grayish-violet corolla with reflexed lobes and a distinctive corona structure. Fruits are erect, curved follicles measuring up to 4–5 cm (1.6–2.0 in) in length.[3]
The species is part of a complex including Asclepias brachystephana, Asclepias uncialis, and Asclepias cutleri, but differs in its broader leaves and shorter corona hood lobules.[3]
Distribution and habitat
The species is restricted to central Utah, particularly the San Rafael Swell region.[1][2] It occurs in desert shrublands, including saltbush communities and pinyon-juniper woodlands, and is sometimes found along drainages.[1]
Conservation
Asclepias ruthiae is ranked as G3 (vulnerable) by NatureServe.[1] It is known from more than 24 occurrences, though overall abundance and trends are poorly understood.[1]
Potential threats include livestock grazing and roadside maintenance activities, although their impacts have not been fully quantified.[1] The species occurs in some protected areas, including Capitol Reef National Park and Bureau of Land Management lands in the San Rafael Swell.[1]
References
- 1 2 3 4 5 6 7 8 "Asclepias ruthiae". NatureServe Explorer. NatureServe. Retrieved 24 March 2026.
- 1 2 3 "Asclepias ruthiae". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 24 March 2026.
- 1 2 3 4 Maguire, Bassett; Woodson, Robert E. (1941). "Two new asclepiads from the southwestern United States". Annals of the Missouri Botanical Garden. 28: 245–248. Retrieved 24 March 2026.