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First Report of Psittacanthus macrantherus on Pinus devoniana and Quercus castanea in Mexico

The mistletoe Psittacanthus macrantherus Eichl. (Loranthaceae) is an important parasite of pines (Pinus spp., Pinaceae) in Mexico (1). It has been reported to parasitize Pinus engelmannii Carr., P. herrerai Mart., P. lawsonii Roezl ex Gord. & Glend., P. lumholtzii Robins & Fern., P. oocarpa Schiede, and P. pseudostrobus Lindl. (1). During July 2005, we found this mistletoe parasitizing P. devoniana Lindl. and Quercus castanea Nee near Route 40 in Sinaloa, Mexico approximately 12 km west of El Palmito (23°30′N, 105°07′W, elevation 1,900 m). The mistletoe was common in P. devoniana, and some trees were severely infected (>10 plants per tree). However, no mortality associated with mistletoe infection in P. devoniana was observed. Only one infected tree of Q. castanea was observed in this area and it was not severely infected. We also observed this mistletoe on P. douglasiana Mart. along Route 40 west and east of El Palmito, but no specimens were collected because plants were very high in the crowns of the infected trees. To our knowledge, this is the first report of this mistletoe parasitizing P. devoniana, P. douglasiana, and Q. castanea (1). Specimens of Psittacanthus macrantherus from P. devoniana and Q. castenea have been deposited at the Deaver Herbarium (ASC), Northern Arizona University, Flagstaff (Accession Nos. 79534 and 79535).

References: (1) B. Geils et al. Mistletoes of North American conifers. USDA For. Serv. Gen. Tech. Rep. RMRS-GTR-98, 2002.