KEY TO THE SPECIES OF PINES 



1. Needles in clusters of 5 (except Pinyons), the cluster sheath decidu- 

 ous and absent on mature needles; one fibro vascular bundle in cross 



section of needle ; cone scales without prickles (except Foxtails) 



Soft Pines. 



2. Needles in clusters of 1-4; cones globose, few-scaled; seed large 



and edible, without wing; western Piny on Pines. 



3. Needles single; Idaho, Nevada, Utah, Arizona, California 



P. monophylla, Singleleaf Pinyon, p. 15. 



3. Needles predominantly in 2's; Colorado, Utah 



P. edulis, Pinyon, p. 15. 



3. Needles in 3's; southern Arizona, New Mexico, Texas 



P. cembroides, Mexican Pinyon, p. 15. 



3. Needles predominantly in 4's; southern California 



P. quadrifolia. Parry Pinyon, p. 15. 



2. Needles in clusters of 5; cones many-scaled. 



4. Cone scales thin, without prickles; seeds long-winged; needles 



slender, 2-4" long, persistent 2-4 years White Pines. 



5. Cones 4-8" long, scales flexible; eastern Canada to Iowa, 



Illinois, and Georgia. P. strobus. Eastern White Pine, p. 9. 

 5. Cones 5-11" (most about 8") long; scales flexible; western 



Canada to Montana and California 



P. monticola. Western White Pine, p. 9. 



5, Cones 12-18" long; scales rigid; Oregon, California, Nevada 

 P. lambertiana, Sugar Pine, p. 7. 



4. Cone scales thick; needles stout, 1-3" long, persistent 5-17 

 years; western. 



6. Cone scales without prickles; seed wing absent or short; 



needles 1 H-3" long, persistent 5-8 years Stone Pines. 



7. Cones 13^-3" long, subglobose, remaining closed; alpine 



from southern Canada to California and Wyoming 



P. albicaulis, Whitebark Pine, p. 11. 



7. Cones 3-10" long, subcylindrical, opening at maturity; 

 through west P. flexilis. Limber Pine. p. 11. 



6. Cone scales with prickles; seed with long wing; needles 



1-1 H" long, resin-dotted, persistent 10-17 years 



Foxtail Pines. 



8. Cones with long, slender prickles, alpine from Colorado 



to California and south 



P. aristata, Bristlecone Pine, p. 13. 



8. Cones with minute, incurved prickles; California alpine. . 



P. balfouriana. Foxtail Pine, p. 13. 



1. Needles in clusters of 2 or 3 (5 in Torrey and Arizona Pine), the 

 cluster sheath persistent (deciduous in Chihuahua Pine) ; 2 flbro- 

 vascular bundles in cross section of needle; cone scales usually armed 



with prickles Hard Pines. 



9. Eastern Hard Pines (Northeast and Central States). 



10. Needles in 3's or 2's and 3's, 3-5" long, twisted; cones 1 }4-3}4" 

 long, persistent on branch. 

 11. Needles in 3's, rigid; cones ovoid with stout prickles; New 



■Pnxnswick and Ontario to Georgia 



P. rigida. Pitch Pine, p. 21. 



11. Needles in 2's and 3's, soft and flexible; cones oblong with 



weak prickles; New York to Missoiu-i and south 



P. echinata, Shortleaf Pine, p. 23. 



10. Needles in 2's. 



12. Needles 4-6" long; cones symmetrical. 



13. Cones 2-3 H" long, persistent several years, falling 

 entire; scales yellow-brown with short spine; widely 

 planted exotic P. nigra, Austrian Pine, p. 17. 



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