Two new species, nomenclatural changes, and range extensions in Mexican Arceuthobium (Viscaceae)

Abstract

Two new species of Arceuthobium are described as parasites of pines (Pinus) in Mexico: A. yecorense infects several species of pines (Pinus) in eastern Sonora, western Chihuahua, and western Durango; A. oaxacanum is known only from two populations in one locality in southern Oaxaca. Arceuthobium vaginatum subsp. durangense Hawksw. &; Wiens is raised to specific status. This taxon was previously known only in Durango and Sinaloa and is reported here for the first time in Jalisco. Arceuthobium gillii subsp. nigrum Hawksw. fe Wiens, also raised to specific status, is widespread in Mexico from Durango to Chiapas on many species of pines. Arceuthobium abietinum Engelm. ex Munz, a common parasite of true firs in the western United States, was found north of Temosachic, Chihuahua, on Abies durangensis -the first report of it from Mexico. With these additions, 22 taxa of Arceuthobium are known from Mexico.

A phylogeny of all species of Arceuthobium (Viscaceae) using nuclear and chloroplast DNA sequences

“…Arceuthobium rubrum occurs primarily in Durango and adjacent Sinaloa, A. oaxacanum is restricted to Oaxaca, and A. yecorense is known from disjunct populations in Chihuahua, Sonora, and Durango. Arceuthobium oaxacanum was first considered a disjunct population of A. rubrum but was later described as a distinct species (Hawksworth and Wiens, 1989). Arceuthobium yecorense was also first described in Hawksworth and Wiens (1989), but based on morphology, it was considered to be most closely related to A. aureum.…”

“…Arceuthobium oaxacanum was first considered a disjunct population of A. rubrum but was later described as a distinct species (Hawksworth and Wiens, 1989). Arceuthobium yecorense was also first described in Hawksworth and Wiens (1989), but based on morphology, it was considered to be most closely related to A. aureum. Both ITS and trnL region sequence analyses result in a clade of the two A. oaxacanum accessions (2035 and 4315, Oaxaca) and this clade is sister to A. rubrum (2071, Durango) followed by A.…”

“…vaginatum, and A. durangense. The latter was named as a distinct species by Hawksworth and Wiens (1989). Arceuthobium vaginatum sensu lato has a wide distributional range, from Utah and Wyoming in the United States (A. vaginatum subsp.…”

Arceuthobium rubrum (Viscaceae) in Mexico

“…Arceuthohium ruhrwn Hawksw. & Wiens (Ruby dwarf mistletoe, Viscaceae) is a distinct species with reddish to brownish-red plants and shiny fruits and is a common parasite of several pines (Finus spp., Pinaceae, Table 1) in northwestern Mexico (Hawksworth and Wiens, 1965, 1972, 1996Mathiasen et al 2008). When a dwarf mistletoe with brownish red plants and shiny, red fruits was discovered in western Oaxaca on Pimis pseudostrobus Lindley by Dr.…”

“…However, based on further studies of two populations of A. ruhrwn in Oaxaca, Hawksworth and Wiens concluded that these populations were sufficiently distinct from those in Durango to describe the Oaxaca populations as a new species: A. oaxacanum Hawksw. & Wiens (Hawksworth and Wiens 1989). They separated A. oaxacanwn from A. ruhrwn based primarily on differences in plant size, plant color, length of pistillate spikes.…”