Madrono 39(1):31-35. 1992.

West rim of Twin Point, southwest edge of Shivwits Plateau, 18 km south of Oak Grove, Mohave County, Arizona, A.M. Phillips, III 30-103, 15 June 1980 (holotype:ARIZ; isotype: ASC, ASU, DES, MNA,MO, NY, UNLV, UNM, US, Lake Mead National Recreation Area Herbarium).

E.O. Wooton first collected the species Rosa stellata in the Organ Mountains, New Mexico, on April 1893, in flower, and again in July 1897, in fruit, the species was described in the 1898 (Wooton 1898). Considered to be in the genus Hesperhodos by Cockerell (1913), it was returned to Rosa by Rehder (1940). Other work has been done by Greene (1910), Rydberg (1918), Hurst (1928), Boulenger (1937), Lewis (1965), and Phillips and Phillips (1982).

Two specimens of Rosa stellata (Ferriss in 1908 and Hawbecker in 1935) were collected in the Grand Canyon region (Kearney and Peebles 1960), but were not included in the monograph of Rosa subgenus Hesperhodos (Lewis 1965). R. stellata or desert rose, was recognized as a species in the Arizona flora (Kearney and Peebles 1960, McDougall 1973, Lehr1978). The Ferriss and Hawbecker collections were noted by Kearney and Peebles (1960):

"In Ferriss' specimen the young twigs are pubescent with soft, stellate hairs and also closely beset with short-stalked glands. Hawbecker's specimen lacks the stellate hairs, having only glandular pubescence, and is therefore technically R. mirifica Greene (R. stellata mirifica Cockerell), but these specimens are otherwise very similar."

In 1980, Arthur M. Phillips, III, recollected the unusual Arizona specimen at a different location. Phillips and Phillips (1982) recognized that this specimen did not fit any of Lewis or Wooton's descriptions. Phillips (1992) described the new taxon as a subspecies. He noted that the northern Arizona plants varied in the presence or absence of the stipitate glands and recognized a single taxon. Noel H. Holmgren (Cronquist et al.1997) later revised the treatment, considering it a variety. The usage of the varietal name proposed by Holmgren is not currently accepted by the Integrated Taxonomic Information System (ITIS) database maintained by the U.S. Department of Agriculture (see www.itis.usda.gov).Botanical nomenclature recognizes intraspecific designations (Porter 1967). These are, in descending order of magnitude, the subspecies, the variety, and the forma, or form. Unfortunately, clear distinctions are not always drawn between subspecies and varieties, and the two categories are used more or less interchangeably. Subspecies and varieties are usually associated with inheritable differences, races, etc. The forma is usually associated with environmentally caused differences of a minor nature. Morphologically distinct taxa in different environments are sometimes called subspecies or ecotypes, while morphologically distinct taxa in similar environments are local variations of one species, or varieties, sometimes called biotypes (Clausen1951).

The Code of botanical nomenclature states explicitly that subspecies are the primary unit into which species are divided, and it is therefore incorrect to use any other infraspecific taxon, such as the variety for the primary division of a species (Raven 1969). It has been suggested that subspecies and varieties be treated as synonyms, to use the former word in scientific nomenclature and the latter in horticultural usage (Pennell 1949). The term variety should perhaps be relegated to informal usage, as the term has gained a multiplicity of meanings quite inconsistent with its employment as a scientific term.