WEYMOUTH PINE, ETC. 309 



green in the mass, the convex side green, the flat sides with 

 silvery stomatal lines, margins serratulate ; basal sheath 

 short and deciduous, orange-reddish. Leaves persisting 

 2 3 years, the tufts collected towards the apex of the 

 shoot. Dying leaves yellow. Cones terete-obtuse, curved, 

 15 18 cm. long. Resin-canals all round the leaf, encircled 

 by thin-walled cells. Venation simple. Vascular bundle 

 undivided. 



[It is almost, if not quite, impossible to distinguish 

 this by the leaves only from the following similar Pines. 



Pinus monticola, Don. Tall tree, much like P. Strobus. 

 Leaves clustered towards the tips of the shoots, slender, 

 12 15 cm. long, trigonal, margins hardly serratulate; 

 3 5 white stomatal lines on the upper flat sides, bright 

 green beneath. Basal sheath pale brown, deciduous, 

 about 2 cm. long. Dying leaves brown. 



Venation simple. Resin-canals encircled by thin- 

 walled cells. Vascular bundle single. 



Twigs red-brown, scarred with leaf-bases. Cone terete- 

 pointed, curved, 20 25 cm. long. 



Pinus excelsa, Wall. Himalayan Pine. Tall tree. 

 Leaves filiform, 10 15 or up to 20 or more cm. long, 

 triquetal, bright green beneath, silvery or greyish on the 

 flattened upper sides, margins minutely serratulate ; basal 

 sheath 2 cm. long, pale brown, deciduous. Leaves per- 

 sistent 3 4 years. Dying leaves yellow. Shoots olive. 

 Cones 18 25 cm., terete-pointed. Venation simple. Resin- 

 canals encircled by thin-walled cells.] 



* Needles not more than 3 in each 

 fascicle. 



-r Needles 3 in each /"sride, trigonal. 



