Mistletoe in the Southwest. 24(9 



and inaccessible in the third, was also seen on the Mexican 

 white pine (P. strobiformis) in both ranges as well as the Santa 

 Catalinas. In this range it likewise occurs upon the Arizona 

 pine, on which it is also found in the Santa Ritas. On this host 

 Razoiimojskya robusta is abundant in many places, attacking 

 young trees as well as old, stems as well as branches, but has 

 never l)een seen to prove fatal. 



The larger genus, excepting a for n found upon white fir, extends 

 from the pine region downward. Phoradendron jniiiperinum 

 and P. bolleaniim, are found only upon the junipers, hence are 

 restricted to the zone of these. Both species occur upoij Junip>erus 

 monosperma and J.pachyphloea.* In the Chiricahuas both have 

 been found rejieatedlv, not onlv upon each host species, but also 

 on the same individual tree of each species. Their ranges may thus 

 cverlajj, but while P.juniperinum extends toward Razoumofsvka 

 above, P. bolleanum apparently follows /. monosperma to the 

 lower limit of the juniper belt. All the preceding but P. bolle- 

 anum, which is narrow-leaved, are leafless, corresponding to the 

 narrow-leaved character of their coniferous hosts. 



With the oak zone, and extending in the deciduous-arboreal 

 seams of the watercourses far down into the desert, but never- 

 theless distinctly Upper Sonoran, appears the broad-leaved and 

 polymorphic P. flavescens. Its variations, their structure and 

 color, correspond to similar variations in host and environment. 

 Some of these have been described by Dr. Engehnann f 

 under the following varietal names. The most common 

 variety, villosum, belongs very largely to the ever- 

 green oaks, but a variety with roughened leaf surfaces also occurs 

 upon the deciduous, but very scabrous hackberry {Celtis reti- 

 culta). P. flavescens orbiculatum, with its small, round, yellow 

 leaves, occurs in exposed places upon Quercus Toumeyi,one of the 

 most xerophytic of oaks. On the other hand, the smooth, dark 

 green P. flavescens macrophyllum is found upon ash {Fraxinus 

 velutina) and other hosts furnishing good water supply and 

 protection from wind and sun. 



The species has its favorite hosts among the oaks as well as 

 the deciduous trees. The oaks with white bark are preferred to 

 those with black bark, whose wood, at least in Quercus Emoryi, 



♦The new combination "Sabina pachyphloca" has been published, but "Juniper ut 



KODOspenna" remains intact. 



fWatson's Botany of California, pp. 104-107, 1880. 



