Overview
San Francisco Peaks ragwort (Packera franciscana) is an endemic dwarf alpine plant in the aster family found only on the talus slopes in the alpine zone on the San Francisco Peaks, within Coconino National Forest, north of Flagstaff, in Coconino County, Arizona. The San Francisco Peaks contain the highest point in the southwestern United States and are home of the only true alpine zone in Arizona. The U.S. Fish and Wildlife Service listed the ragwort, with critical habitat, in 1983.
Since the U.S. Fish and Wildlife Service listed the ragwort, the common and scientific names changed from San Francisco Peaks groundsel (Senecio franciscanus) to San Francisco Peaks ragwort (Packera franciscana).
Scientific Name
Identification Numbers
Characteristics
Habitat
San Francisco Peaks ragwort occurs on the volcanic San Francisco Peaks, which rises abruptly from 2,134 meters (7,000 feet) to an elevation of 3,851 meters (12,633 feet). The plant grows in the alpine tundra where it occurs between 3,147 to 3,834 meters (10,322 to 12,576 feet) with the most plants occurring in the zone from 3,528 to 3,605 meters (11,572 to 11,824 feet) elevation. The ragwort grows on gravelly, sandy loams associated with talus in alpine fellfield, or plant community. The plant exists mainly on talus slopes as a primary successional species.
Physical Characteristics
The San Francisco Peaks ragwort is 3 to 10 centimeters (1.25 to 4 in) tall, in tufts to 7.6 centimeters (3 in) wide. Stems generally arise singly from the upturned ends of creeping rhizomes or are sometimes loosely clustered. Leaves are deeply lobed, with upper leaves smaller than lower leaves. Leaves are alternate; oval to roundish, downy, crinkly and toothed; to 5 centimeters (2 in) long. Seeds are glabrous, or smooth.
Small yellow flowers heads that are about 1.0 centimeters (0.4 in.) wide, borne singly, or up to six in a compact cluster, with each containing eight to 13 yellow ray flowers. Leaves are grayish green, and edged in reddish purple.
Life Cycle
The San Francisco Peaks ragwort growing season is from June to September when the mean air temperature is 9 Celsius (48 degrees Fahrenheit). Flowering generally occurs from late July and through early September. Fruits mature in mid-September to early October. The plants enter winter dormancy by mid-October.
San Francisco Peaks ragwort grows low to the rocky ground where it occurs. Reproduction is primarily vegetative by mat-forming rhizomes, an underground plant stem that sends out roots and shoots from its nodes, although sexual reproduction also occurs from mature achenes, orfruit. The ragwort is adapted to natural soil movement due to frost action and gravity on the steep slopes of the San Francisco Peaks. Frost action and gravitational movement break up the clones, which separates plants and results in the plant spreading.
Geography
Ragwort populations occur on Humphreys, Agassiz, Fremont and Doyle peaks, and along the north rim that extends northeast from Humphreys Peak on the San Francisco Peaks, within Coconino National Forest, north of Flagstaff, in Coconino County, Arizona. It is difficult to determine from existing information if there has been any trend in spatial distribution of San Francisco Peaks ragwort or a change in its historical range. Data indicates that the plant inhabits much of the same area it occupied when botanists first described it in 1884.
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