December 2012 Number 1 - Utah Native Plant Society

Utah Native Plant Society
East Meets West: Rare Desert Alliums in Arizona
John L. Anderson,
US Bureau of Land Management, Phoenix, AZ, retired
Abstract. Two previously poorly known desert species of Allium in Arizona, A. bigelovii and A. parishii, were investigated
to determine their actual rarity and conservation status. Each approached Arizona from different deserts
and opposite directions: Allium bigelovii from the Chihuahuan Desert in New Mexico and Allium parishii from the
Mohave Desert in California. The status of Allium bigelovii was made difficult to understand by the many misidentifications
of herbarium specimens. A review of herbarium specimens and field visits determined that Allium bigelovii is
a Chihuahuan Desert species that enters southeastern Arizona and is disjunct farther west into the Sonoran Desert on
unusual lacustrine soils. Allium parishii was only known from historic collections in two mountain ranges in western
Arizona. These historic locations were relocated. Although these two Allium species normally occur nearly 500 km
apart and in different deserts, they approach within less than 100 km in the Sonoran Desert of western Arizona.
There are 96 species of Allium L. in North America
north of Mexico with thirteen species in Arizona
(McNeal and Jacobsen 2002). The taxonomy of Allium
in Arizona is largely unchanged since the monograph of
Ownbey (1947). Three of the species recognized there
are now treated as varieties: Allium nevadense S. Wats.
var. cristatum (S. Wats.) Ownbey as A. atrorubens S.
Wats. var. cristatum (S. Wats.) D. McNeal; A. palmeri
Wats. as A. bisceptrum S. Wats. var. palmeri (Wats.)
Cronquist; and A. rubrum Osterhout as A. geyeri S.
Wats. var. tenerum Jones. The thirteen Arizona species
are rather equally divided through the diverse Arizona
habitats of deserts and mountains, aridlands and wetlands,
low and high elevations, and northern and southern
floristic affinities. Two of the desert species, Allium
bigelovii S. Wats. (Figure 1) and A. parishii S. Wats.
(Figure 2), have been poorly known in Arizona, but for
different reasons. The taxonomic identity of the former,
and consequently its real range and habitat in Arizona,
has been confused by the many misidentifications of
herbarium specimens; and, the geographic status of the
latter in Arizona was made unclear by its few historic
records in the state.
The range of Allium bigelovii was described by Ownbey
(1947) as “…southwestern New Mexico, northwestward
across central Arizona to Mohave County.” In Arizona
he cited five historic collections: (isotype, Palmer
532 NY 1876 (Figure 3); Rusby 839 NY 1883; Crooks
et al ARIZ 1939; Crooks & Darrow ARIZ 1938; and
Benson & Darrow POM 1941), all from central Arizona
(Figure 4). The type collection of A. bigelovii is from
Cook’s Springs (Bigelow s.n.) in southwestern New
Mexico (Watson 1871). Several collections at RSA
(Eastwood 8276, Greene s.n.., Jones s.n.) and at NY
(Greene s.n., Rusby s.n.., and Holmgren 6891) document
its historic occurrence in southwestern New Mexico.
Sivinski (2003) described the habitat and range of
Figure 1. Allium bigelovii.
Figure 2. Allium parishii.
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