Border piñon (Lanner 1981).
Subsection Cembroides. Syn: P. cembroides subsp. cembroides var. bicolor Little 1968; P. culminicola var. discolor (Bailey and Hawksworth) Silba 1985 (Farjon & Styles 1997).
The validity of this taxon is greatly disputed. At one extreme, Kral (1993) summarily dismisses its existence altogether, and Farjon and Styles (1997) regard it, combined with P. johannis Robert-Passini, as merely a variety of P. cembroides (var. bicolor Little) while at the other extreme, Perry (1991) and Price et al. (1998) regard it as a valid species distinct in its own right. An intermediate view is taken by Passini (1994), who treats P. discolor as a synonym of P. johannis. It is clearly very close to that species but does differ slightly, and might best be treated as a variety of it, but the combination Pinus johannis var. bicolor has not yet been published.
There have been no reports of any natural hybridization with P. cembroides, despite frequent intermingled occurrence, which strongly supports specific distinction from P. cembroides. Pending further research, it is retained as a species here.
The view of Silba (1985) that it and P. johannis are varieties of P. culminicola has some merit in showing that they are more closely related to P. culminicola than to P. cembroides (a fact subsequently demonstrated by Malusa (1992)), but is not widely followed.
As Pinus johannis except:
Some of these differences are based on small sample sizes, and may prove inconclusive with further research. Differences in the composition of the turpentine have also been reported (Zavarin & Snajberk 1986), but the validity of this research has been questioned (Farjon & Styles 1997).
S Arizona & New Mexico. Notably, Kitt Pk. and the Santa Catalina Mtns (Lanner 1981). Mexico: Sonora, Chihuahua and Durango at 1500-2400 m (Perry 1991). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001).
Potentially a valuable slow-growing ornamental species for small gardens in drought-prone areas, but it is scarcely in cultivation yet. USDA hardiness zone 8.
This species is one of the principal hosts for the dwarf mistletoes Arceuthobium pendens (Hawksworth and Wiens 1996).
Bailey, D. K. and F. G. Hawksworth. 1979. Pinyons of the Chihuahuan Desert region. Phytologia 44:129-133. Available: www.biodiversitylibrary.org/item/47046, accessed 2011.05.21.
Zavarin, E. and K. Snajberk. 1986. Monoterpenoid differentiation in relation to the morphology of Pinus discolor and Pinus johannis. Biochemical Systematics and Ecology 14: 1-11.
Much of this page was prepared by M.P. Frankis, 1999.02.
Last Modified 2012-11-23