PIN us 



PINUS 



1349 



G. Buds cyl Indri c, 

 tv i t h spreading 

 scales little or not 

 resinotis: I vs. 8-12 

 in. long, dark 

 green, in S's and 



S's 22. Cubensis 



QG. Buds oblong-ovate, 

 resinous: Irs. 6-9 

 in. long, light or 

 slightly bluish 



green 21. Taeda 



GGG. Buds ovate, acumi- 

 nate, resinous: Ivs . 

 5-11 in. long, dark 

 yellowish green.. .20. ponderosa 

 FF. Length of Ivs. S-7 in. 

 (See also No. 29.) 

 G. Character of Ivs. 

 slender. 

 H. Foliage pale yel- 

 lowish or bluish 

 green: buds ob- 

 long-ovate , 



dark brown 26. tuberculata 



HH. Foliage bright 

 green : buds 

 ovate, bright 

 chestnut-brown.27. radiata 

 GG. Character of Ivs . 

 stout. 

 H. Fo rm f bud s 

 thick, orate, 

 acute or acumi- 

 nate 20. ponderosa, 



var.scopulorum 

 HH. Form of buds ob- 

 long-ovate 28. rigida 



AAA. Number of Ivs. 2. 



B. Branchlets glaucous. 



c. Buds very resinous 30. Virginiana 



cc. Btids not or little resinous. 

 D. Hue of Irs. dark bluish 



green 29. echinata 



DD. Hue of Irs. bright green. .iS. densiJlora 

 BB. Branchlets not glaucous. 

 C. Length of Ivs. 1-S% in. 

 D. Branchlets brown or 

 orange : re s in -d uct s 

 parenchymatous . 

 E. Character of Ivs. slen- 

 der: branchlets brown.32. claiisa 

 EE. Character of Ivs. stout, 

 twisted: branchlets 

 orange or orange- 

 brown. 

 F. Lvs. l-Syi in. long. 



G. Besin-ducts 1 or 2.33. contorta 

 GG. Besin-ducts 2-5 . . .34. pungens 

 FF. Lvs. Y-i.-! in. long ...31. divaricats 

 DD. Branchlets dull greenish 

 yellow or greenish 

 broivn: resin-ducts pe- 

 ripheral. 

 E. Character of lvs. slen- 

 der: buds not resin- 

 ous 41 Halepensis 



EE. Character of lvs. stout: 

 buds coated with resin. 



F. Generally a tree 44. sylvestris 



FF. Generally a shriib...^5. montana 

 CO. Length of lvs. 3-9 in. 



D. Color of buds whitish or 



grayish white 38. Thunbergi 



DTi. Color of buds brown. (See 



also No. 41.) 



E. Scales of the oblong 



buds with reflexed 



tips, chestnut-brown. 



F. Habit of lvs. very 



slender and thiH...i2. Massoniana 

 FF. Habit of lvs. stiff and 

 rigid. 



G. Buds resinous 35. muricatf 



GG. Buds not resinous. 

 H. Besin-ducts par- 

 enchymatous. ..37. Pinaster 

 HH. Besin - ducts pe- 

 ripheral 39. Pinea 



BE. Scales of the thick 

 ovate-acuminate buds 

 with the tips not re- 

 flexed, light brown, 

 resinous. 

 V. Foliage lustrou s , 

 resin-ducts periph- 

 eral 38. resinosa 



FF. Foliage dull : resin- 

 ducts parenchyma- 

 tous 3C. Laricio 



Key Based on Cones and Seeds. 



Cone-scales thin at the apex, 

 with a marginal obtuse umbo: 

 number of lvs. 5: sheaths de- 

 ciduous : fibro- vascular 

 bundle 1: wood soft and light.. 

 Strobus. 

 B. IVings longer than seed: cones 

 long and slender: resin- 

 ducts of lvs. peri pheral. 

 Bustrobi. 

 C. Scales with broad, rounded 

 apex. 

 d. Lvs. slender: branchlets 

 usually glabrous.. . 



. 1. 

 2. 

 3. 

 DD. Lvs. stout: branchlets 

 puberulous or pubescent. 4. 

 5. 

 cc. Scales with elongated and 

 tapering, at last recurved 



apex 



B. Wings shorter than seeds or 



wanting: cones more or less 



ovate, with thickened scales. 



Cembrce. 



c. Margin of lvs. entire: 



branchlets glabrous, light 



brown 



CC. Margin of lvs. serrulate: 

 branchlets pubescent . 

 D. Seeds with narrow wing: 

 resin-ducts peripheral. . 

 DV. Seeds wingless: resin- 

 ducts parenchy matous . . 



ezcelsa 



Peuce 



Strobus 



monticola 

 Lambertiana 



6. Ayacahuite 



flexilis 



8. parviflora 



Koraiensis 

 Cembra 



A. Cone-scales more or less thick- 

 ened at the apex, with the often 

 sjiiny umbo in the middle of the 

 transversely ridged apophy- 

 sis. Pinaster. 

 B. Sheaths caducous or curling 

 back and tardily deciduous: 

 fibro - vascular btindle 1 : 

 resin-ducts peripheral. 

 C. Seeds short-ivinged : num- 

 ber of Irs. 1-4, only occa- 

 sionally 5. 

 D. Margin of lvs. serrtilate, 

 3; sheaths caducotis. 



Gerardiancs 11. Bungeana 



DD. Margin of lvs. entire ; 

 sheaths curling back and 

 falling offend of the first 

 year. Cembroides. 



E. Number of lvs. 3-5 12. Parryana 



EE. Number of lvs. 1-3 13. edulis 



M. monophylla 

 cc. Seeds with long wing: num- 

 beroflvs.5: margin entire. 



Balfouriance 15. Balfouriana 



BB. Sheaths persistent: fibro-vas- 

 cular bundles 2: margin of 

 lvs. serrulate. 



