PINUS 



PINUS 



2635 



cc. Cones 1O-18 in. long: branchlets 



pubescent. 

 D. Scales of cone rounded: hs. 



stout 10. Lambertiana 



DD. Scales of cone with elongated 

 and more or less recurved 



apex: hs. slender 11. Ayacahuite 



AA. Umbo of scales dorsal. 



B. Seeds wingless or with very short 



wing: cones green at maturity, 

 c. Margin of If. entire; Ivs. %-l}4 



in. long. 

 D. Number of hs. 3 or 4- 



E. Lrs. usually 4 12 - Parryana 



EE. Lrs. usually 3 13. cembroides 



DD. Number of hs. 1 or 2. 



E. Lrs. usually 2, sometimes 3. 14. edulis 

 EE. Lrs. usually 1, sometimes 2. 15. monophylla 

 cc. Margin of If. serrulate: hs. 3, 



2-4 in. long 16. Bungeana 



BB. Seeds with long wing: cones purple 



at maturity. 

 c. Cones with minute incurved 



prickles 17. Balfouriana 



cc. Cones with long slender prickles. . 18. aristata 



II. PITCH PINES (Diploxylon). 



Wood usually heavy, coarse-grained, generally dark- 

 colored, sap-wood pale, often thick: sheaths of If.-clusters 

 persistent (in the following species): Ivs. with 2 fibre-vascu- 

 lar bundles, serrulate: umbo of cone-scales dorsal. 

 A. Seed-wing very short or long and 



adnate. 

 B. Wing very short, deciduous: hs. 2, 



5-8 in. long 19. Pinea 



BB. Wing long, adnate: hs. 3, 8-12 in. 



long, 

 c. Apophysis broad-pyramidal; 



seed Yiin. long 20. canariensis 



cc. Apophysis elongated and more or 

 less recurved; seed %-l in. 



long 21. longifolia 



AA. Seed-wing articulate. 



B. Wing of seed membranous, long, 

 c. Lrs. in 2's: cones deciduous, de- 

 hiscent at maturity, in No. 29 

 persistent and hs. sometimes in 

 S's. 

 D. Resin-ducts external. 



E. Branchlets bloomy: hs. 2%- 



5 in. long 22. densiflora 



EE. Branchlets not bloomy. 

 F. Lvs. 4~8 in. long. 



G. Color of branchlets yel- 

 lowish brown: Ivs. 

 dark green, slender 



and thin 23. Massoniana 



GG. Color of branchlets 

 orange: hs. stout, 



light green 24. resinosa 



FF. Lrs. %-3 in. long. 



G. Umbo obtuse, gray: 

 hs. more or less bluish 



green 25. sylvestris 



GG. Umbo more or less 

 prickly, surrounded 

 by a Mack marking: 



hs. bright green 26. montana 



DD. Resin-ducts medial, or medial 



and external. 

 E. Cones deciduous: resin-ducts 



medial. 



F. Winter buds brown, resin- 

 ous, ovate-oblong 27. nigra 



FF. Winter buds grayish white, 



cylindric 28. Thunbergii 



EE. Cones tenaciously persist- 

 ent: hs. in 2's and S's 29. sinensis 



cc. Lrs. in S's or in 2's and S's. 

 D. The cones deciduous. 

 E. Resin-ducts medial. 



F. Young cones subterminal. 

 G. Branchlets orange: 



cones 3-6 in. long. . .30. ponderosa 

 GG. Branchlets glaucous: 



cones 5-15 in. long. .31. Jeffreyi 



FF. Young cones lateral. 



G. Lvs. 3-5 in. long 32. echinata 



GG. Lvs. 6-9 in. long 33. Taeda 



EE. Resin-ducts internal: hs. 



8-18 in. long. 



F. Winter buds whitish: cone 

 dull brown, 6-10 in. 



long 34. palustris 



FF. Winter buds light brown: 

 cone lustrous, brown, 



3-6% in. long 35. caribsea 



DD. The cones tenaciously per- 

 sistent, often serotinous: 

 resin-ducts medial (except in 

 No. 36). 

 E. Lvs. in 2's. 



F. Resin-ducts external: 



umbo obtuse 36. halepensis 



FF. Resin-ducts medial. 

 G. Cones symmetrical. 



H. Lrs. 5-8 in. long 37. Pinaster 



HH. Lvs. 1-SYi in. long, 

 i. Prickles of cone 



stout 38. pungens 



n. Prickles of cone 



slender. 



j. Cones remaining 

 closed for 

 many years.. .39. clausa 

 jj. Cones opening at 



maturity 40. virginiana 



GO. Cones unsymmetrical. 

 H. Length of Ivs. less 



than 4 in. 

 I. Cones not prickly, 



lateral 41. Banksiana 



n. Cones prickly, sub- 

 terminal . . .42. contorta 



HH. Length of hs. 4~6 in.: 

 cones with stout 

 and large prickles. . 43. muricata 

 EE. Lrs. in S's: cone prickly. 

 F. Cones symmetrical. 



G. Length of hs. 6-8 in.: 



cones remaining 



dosed for 1 or 2 j/ears.44. serotina 



GG. Length of hs. 3-5 in.: 



cones opening at 



maturity 45. rigida 



FF. Cones unsymmetrical. 

 G. Prickles of cone mi- 

 nute: upper part of 



trunk rough 46. radiata 



GG. Prickles of cone stout: 

 upper part of trunk 



smooth 47. attenuata 



BB. Wing of seed thick, short: hs. 3 or 5, 

 6-13 in. long: cones large. 

 c. Lvs. in S's, 6-12 in. long. 



D. Cone conical-oblong; wings 

 about 1 in. longer than the 



seed: hs. stout 48. Coulteri 



DD. Cones broadly ovate; wing 

 about l /&n. longer than the 

 seed: hs. slender, flexible. .49. Sabiniana 

 cc. Lrs. in S's, rigid, 8-13 in. long: 

 cone broadly ovate; seed short- 

 winged 50. Torreyana 



NO. 2. KEY FOB DETERMINING PINES WITHOUT CONES. 



(Compare Figs. 2958-2961.) 



A. Number of hs. 5, only occasionally 3 



or 4- 

 B. Sheaths deciduous: fibro-vascular 



bundle 1. 



c. Edges of hs. serrulate. 

 D. Length of hs. 1 14-8 in. 



E. Branchlets glabrous or 



nearly so. 

 F. The hs. 6-8 in. long: 



branchlets glaucous .... 7. excelsa 

 FF. The hs. 3-6 in. long: 

 branchlets not glaucous. 

 G. Tree a rather dense 

 pyramid with ascend- 

 ing branches 6. Peuce 



