PINUS 



PINUS 



1349 



G. Buds cyli n d r i c, 

 with spreading 

 scales little or not 

 resinous: Ivs. 8-13 

 in. long, dark 

 green, in Ps and 



3's 22. Cubensis 



GG. Buds oblong -ovate, 

 resinous: Ivs. 6-9 

 in. long, light or 

 slightly bluish 



green 21. Taeda 



GOG. Buds ovate, acumi- 

 nate, resinous: Ivs. 

 5-11 in. long, dark 

 yellowish green... 20. ponderosa 

 FF. Length of Ivs. 3-7 in. 



(See also No. 29.) 

 G. Character of Irs. 



slender. 



H. Foliage pale yel- 

 lowish or bluish 

 green: bitds ob- 

 long -ovate , 



dark brown 26. tuber culata 



HH. Foliage bright 



green: buds 



ovate, bright 



chestnut-brown. 27. radiata 



GG. Character of Ivs . 



stout. 



H. Form of buds 

 thick, ovate, 

 acute or acumi- 

 nate .. ...20. 



HH. Form of buds ob- 

 long-ovate 28. 



AAA. Number of Ivs. 2. 



B. Branchlets glaucous. 



c. Buds very resinous 30. 



CO. Buds not or little resinous. 

 D. Hue of Ivs. dark bluish 



green 29. 



DD. Hue of Ivs. bright green. A3. 

 BB. Branchlets not glaucous. 

 c. Length of Ivs. 1-3% in. 

 D. Branch let s brown or 

 orange: resin-ducts 

 parenchymatous. 

 E. Character of Ivs. slen- 

 der: branchlets brown.32. 

 EE. Character of Ivs. stout, 

 twisted: branchlets 

 orange or orange- 

 brown. 

 F. Lvs. l-SYi in. long. 



G. Resin-ducts 1 or 2.33. 

 GG. Resin-ducts 2-5 ...34. 

 FF. Lvs. Yv-1 in. long ...31. 

 DD. Branchlets dull greenish 

 yellow or greenish 

 brown: resin-ducts pe- 

 ripheral. 



E. Character of h>s. slen- 

 der: buds not resin- 

 ous 41 



EE. Character of Ivs. stoiit: 

 buds coated with resin . 



F. Generally a tree 44. 



FF. Generally a shrub.. .45. 

 CC. Length of Ivs. 3-9 in. 



D. Color of buds ichitish or 



grayish white 38. 



DD. Color of buds brown. (See 



also No. 41.) 



E. Scales of the oblong 

 brids with re flexed 

 tips, chestnut -brown. 

 F. Habit of Ivs. very 



slender and thin..A2. 

 FF. Habit of Ivs. stiff and 

 rigid. 



ponderosa, 

 \ar.scopulorum 



rigida 

 Virginians 



echinata 



densiflora 



clausa 



contorta 

 pungens 

 divaricata 



Halepensis 



sylvestria 

 montana 



Thunbergi 



Massoniana 



G. Buds resinous 35. muricatt 



GG. Buds not resinous . 

 H. Resin-ducts par- 

 enchymatous .. .37. Pinaster 

 HH. Resin -ducts pe- 

 ripheral 39. Pinea 



WE. Scales of the thick 

 ovate-acuminate buds 

 with the tips not re- 

 flexed, light brown, 

 resinous. 



F. Foliage lustrous, 

 resin-ducts periph- 

 eral 38. resinosa 



FF. Foliage dull : resin- 

 ducts parenchyma- 

 tous 36. Laricio 



KEY BASED ON CONES AND SEEDS. 



A. Cone-scales thin at the apex, 

 with a marginal obtuse umbo: 

 number of Ivs. d: sheaths de- 

 ciduous: fibro- vascular 

 bundle 1: wood soft and light.. 

 STROBUS. 



B. Wings longer than seed: cones 

 long and slender: resin- 

 ducts of Ivs. peripheral. 

 Eustrobi. 

 C. Scales with broad, rounded 



apex. 



D. Lvs. slender: branchlets 

 usually glabrous 1. 



2. 

 3. 



DD. Lvs . stout : branchlets 

 puberulous or pubescent. 4. 

 5. 



excelsa 

 Peuce 



Strobus 



monticola 

 Lambertiana 



cc. Scales with elongated and 

 tapering, at last recurved 

 apex ..................... 6. Ayacahuite 



BB. Wings shorter than seeds or 

 wanting: cones more or less 

 ovate, with thickened scales. 

 Cembrce. 



c. Margin of Ivs. entire: 

 branchlets glabrous, light 

 brown .......... . ......... 7. Hexilis 



CC. Margin of Ivs. serrulate: 



branchlets pubescent. 

 D. Seeds with narrow wing: 



resin-ducts peripheral. . 8. parviflora 

 DD. Seeds wingless: resin- 



ducts parenchymatous.. 9. Koraiensis 



10. Cembra 



AA. Cone-scales more or less thick- 

 ened at the apex, with the often 

 spiny umbo in the middle of the 

 transversely ridged apophy- 

 sis. PINASTER. 



B. Sheaths caducous or curling 

 back and tardily deciduous: 

 fibro - vascular bundle 1 : 

 resin-ducts peripheral. 

 c. Seeds short-winged : num- 

 ber of h's. 1-4, only occa- 

 sionally 5. 



D. Margin of Ivs. serrulate, 

 S; sheaths caducous. 

 Gerardiance ............ 11. Bungeana 



DD. Margin of Ivs. entire ; 

 sheaths curling back and 

 falling offend of the first 

 year. Cembroides. 

 B. Number of Ivs. 3-5 ---- 12. Parryana 



EE. Number of Ivs. 1-3 ____ 13. edulis 



M. monophylla 



CO. Seeds with long wing: num- 

 ber of Ivs. 5: margin entire. 

 BalfouriancB ............. 15. Balfouriana 



BB. Sheaths persistent: fibre-vas- 

 cular bundles 2: margin of 

 Ivs, serrulate, 



