382 A HANDBOOK OF CONIFERS 



planting must also be avoided. Trees affected by this fungus 

 should be dug up carefully and burned, a trench 2 ft. wide and 

 2| ft. deep being dug round the affected area to prevent the spread 

 of the disease. 



Large trees of the Arolla pine are to be seen in many places, 

 notably at Walcot, Shropshire, the seat of the Earl of Powis, 

 where it was planted extensively about 1820. Several of these 

 trees remain. 



Elwes and Henry he. cit. v, 1035 (1910). 



Pinus cembroides, Zuccarini. (Fig, 85.) 

 Mexican Nut Pene. 



Pinus fertilis, Roezl ; P. futilis, Sargent ; P. Llaveana, Schiede ; P. 

 osteosperma, Engelmann. Mexican Pine ; Mexican Pinon ; Nut Pine ; 

 Piiion ; Pinyon ; Stone Pine ; Three-leaved Nut Pine. 



A bush or low tree 15-25 ft., or, in favourable positions, 

 upwards of 40 ft., high, with a short trunk and round, bushy head. 

 Bark on mature trees thin and scaly. Young shoots, slender, 

 glaucous, minutely downy, or without down. Winter buds about 

 ^ in. long, with densely imbricated scales. Leaves usually in 

 threes, but sometimes soUtary, or in pairs, fours or fives, persisting 

 3-4 years, closely arranged, incurved, 1-2 in. long, margins entire, 

 apex sharp-pointed, stomata on each surface, resin canals marginal, 

 segments of leaf-sheath persisting, but rolling backwards to form 

 a rosette round the base of the leaf -cluster. Cones globular or 

 egg-shaped, 1-2^ in. long, and the same in width, yellowish or 

 reddish brown ; scales few, large, fiat, wide-spreading in the 

 mature cone. Seeds |— | in. long, ^| in. wide, dark brown below, 

 rather hghter above, wingless, edible. 



The above description appUes to P. cembroides in its widest 

 sense, and includes P. edulis, P. monophylla, and P. Parryana, 

 which have until recently been considered as distinct species. 

 We follow Voss in regarding them all as varieties of one species. 



Var. edulis, Voss. (Fig. 85.) 

 Two -LEAVED Nut Pine. 



P. cembroides, Gordon (not Zuccarini) ; P. edulis, Endlicher ; P. 

 Fremontiana, Gordon (not Endlicher) ; P. monophylla, var. ediilis. 

 M. E. Jones ; Caryopitys edulis, Small. New Mexican Pinyon ; Nut 

 Pine ; Pinyon ; Piiion ; Pine ; Rocky Moiontain Nut Pine. 



Not differing materially from P. cembroides except in the 

 leaves being usually stouter and in pairs, occasionally in threes 

 or singly, and not so crowded on the branchlets. Distribution 

 more northerly than P. cembroides. Discovered by Dr. Wishzenus 

 in New Mexico in 1846. There is a plant at Kew 23 ft. high. 



