Adenophyllum wrightii

This is an annual species with smooth, upright stems, up to 30 centimeters tall. The leaves are deeply lobed with 5-8 linear, spine-tipped segments. Flower heads occur on short stalks. The flower heads have very small and inconspicuous ray flowers that do not surpass the disk. Achenes have a pappus of 20 scale-like segments; the 10 inner ones each divided into 3-cleft and 3-awned segments. It is a summer annual, blooming in September.

Adenophyllum wrightii var. wrightii is an annual with inconspicuous flowers. Separated from the more southerly-distributed A. wrightii var. pulcherrima by having shorter, more inconspicuous rays (lamina less than 3 mm long). Variety pulcherrima occurs farther south in Jalisco and Queretaro, Mexico on wet clay soils in roadsides and flats. It flowers earlier than variety wrightii starting in August (Strothers 1969). Little is known about this variety as well, and it seems to have a very limited distribution.

The most similar species in this genus is Adenophyllum anomalum, which has a shorter involucre-to 4.5 mm. and phyllaries ca. 8. A. wrightii has an involucre 5 to 8 mm high, and 9 - 13 phyllaries. A. anomalum occurs in central-western Sonora, south on the Pacific slope to Durango and Western Sinoloa and is closely related to the element. It flowers August to February. It is not known to occur within the range of A. wrightii (Strothers 1969).

Low lying areas that form ephemeral pools in late summer seem to be the best habitat for the species according to notes on herbarium specimens. More data must be collected to determine more details regarding the specific ecological needs of Wright's dogweed. It is not known if the element prefers these niches. However it is likely that if it does, the apparent rarity Wright's dogweed may be influenced by the habitat.

Following is the reply of David Ferguson of the Rio Grande Botanical Garden in New Mexico who the author contacted to find out more about the niche:

"I can understand why the plant might not be seen often [if it is specific to ephemeral pools], as ephemeral pools are far between and often go years without seeing enough water to get the annual plants adapted to them to grow. This is probably too far northeast, but north of Los Lunas on the west side of I-25 is a large ephemeral pool. It has not had water in it for several year, but this year it has. The last time it filled up there were many annuals there which I have not seen since (mostly yellow composites, probably mostly Helenium?). This year I see a yellow glow to the sight again. It is very cattle beaten, but the plants seem to come back every wet year. This pool may be the type locality for a threatened species of grasshopper, which only occurs in such areas.

"Probably a bit closer to the area of interest are a number of ephemeral pools along Highway 117 between El Malpais and Highway 36 in Cibola County. I do not know if they filled this year, but the last time they did they were full of critters which I hadn't seen in pools since growing up on the Plains (tadpole shrimp, fairy shrimp, spadefoot tadpoles, etc.). I seem to remember a small-flowered yellow composite growing in the wet areas. The grasshopper has been found here too, and well down into Chihuahua, but is rarely seen (except by the intrepid David Lightfoot)." (pers. comm. 1999)

If this species is indeed native to these niches, it is possible that its life history evades our observation because it only occurs in the wettest of years.

The element is also mentioned to be found in "open slopes" between 4,500 and 8,000 feet in elevation (Martin & Hutchins 1981). It has also been collected near "open plains beyond the pines" in the vicinity of "shallow ponds" (Davis 1936).

Sandy or silty soils in swales and drainages in pinyon-juniper woodland; 2100-2200 m (7000-7200 ft) in New Mexico (Sivinski 2000).

Pringle's notes on his collection of this species (Davis 1936) may suggest some associated species. But the notes are not specific enough to determine if the specimens he collected on that day were from the same location or if there was much travelling between them. However it is likely this species occurs with grasses and is possibly associated with moist soil species like Delphinium tenuisectum, Pectis aquatica, Tagetes pringlei, Eriocaulon pringlei. Due to lack of data, however, virtually nothing is known of the ecological communities of Wright's dogweed.

The dainty sulfur (Nathalis iloe) is known to feed on composites (Asteraceae), and Dyssodia pentacheata (closely related to the element) is recorded as a food plant for this species. Dainty sulfurs prefer fresh, not woody, herbaceous plants, especially seedlings. It is very likely the element can serve as a food plant for the dainty sulfur, as it occurs within the geographic distribution and elevation of the element (Jim Brock pers. comm.).

Reproduction is from seed as the species is an annual. No data suggests that plants perennialize or reproduce asexually. The element flowers in September (Strothers 1969).