Fouquieria columnaris, the Boojum tree or cirio () is a tree in the ocotillo family, whose other members include the ocotillos. Some taxonomists place it in the separate genus Idria. It is nearly endemic to the Baja California Peninsula (both the northern and southern states), with only a small population in the Sierra Bacha of Sonora, Mexico. The plant's English name, Boojum, was given by Godfrey Sykes of the Desert Laboratory in Tucson, Arizona, and is taken from Lewis Carroll's poem "The Hunting of the Snark".
Description
This plant is a columniform, upwardly tapering tree. The central axis of the plant is homologous to the single stem of other species. It has a cortical water-storage network, a feature unique to the family. the second tallest succulent after Euphorbia ampliphylla.
The flowers bloom in August and September regardless of rainfall; The flowers have short, cream-yellow corollas, with the limb of the petals inflexing around the filaments of the stamens. The anthers and stamens protrude out, while the stigma is protected by the inflexed petal limbs. The flowers are visited by at least 15 species of bees in 11 genera, who pry open the inflexed corolla limbs to obtain the sweetened nectar and contact the protected stigma.
Taxonomy
This species is most similar to two Fouquieria native to south-central Mexico, Fouquieria fasciculata and Fouquieria purpusii, as they share a succulent xylem, widely spaced decurrent leaf bases, and small decandrous (ten-stamen) flowers. In the two species, they are initially woody, and their succulent xylem develops only in the lower portion of their main stem. In contrast, the Boojum tree has a succulent xylem from its initiation, with the primary thickening occurring from the meristem. The chromosome number of this species is 36. It is also found on Isla Angel de la Guarda in the Gulf of California. On mainland Mexico, it is also found in a small area south of Puerto Libertad in coastal Sonora. The annual rainfall within its region only averages about 73 to 140 mm, mainly from January to April and in lesser amounts in August through September. Rainfall is unreliable and sometimes years may pass without heavy rainfall.
left|thumb|Numerous plants on the horizon
The peculiar distribution pattern of the mainland boojums has led Mexican botanists to conclude that they were probably transplanted to the mainland by the indigenous Seri people, who lived in this area and still live on communal property south of this location. The Seri name for this plant is cototaj . In Seri belief, touching this plant will cause strong winds to blow (an undesirable state). Given this belief, the hypothesis that the Seri people transplanted it is doubtful.