Illustrations of Conifers. 31 



KEY TO PICEA. 



SECTION I. 



LEAVES FLATTENED WITH STOMATA ONLY ON THE DORSAL SURFACE. i 

 I . Branchlets glabrous. 



P. ajanensis, Fischer. Buds broadly conic, with scales rounded in margin. Leaves thin, 

 slightly keeled on both surfaces, blunt or ending in short points ; those on the upper 

 side of the shoot more or less imbricate in arrangement, those below spreading laterally 

 in two ranks. 



P. sitchensis, Carriere. Buds ovoid with obtuse scales. Leaves deeply keeled on the ventral 

 green surface, almost convex on the dorsal white surface, ending in sharp, thorn-like car- 

 tilaginous points ; arranged as in P. ajanensis. 



P. gpinulosa, Henry. Buds ovoid with obtuse scales. Leaves deeply keeled on both surfaces, 

 slender, sharp-pointed ; in an imperfect radial arrangement. 



II. Branchlets pubescent with short hairs. 



P. Otnorika, Bolle. Branchlets with brown pubescence. Buds ovate-conic, with outer scales 

 ending in long subulate points. Leaves flattened but thick, obtuse, or ending in a short 

 point, arranged as in P. excelsa. 



P. Breweriana, Watson. Branchlets pendulous, with grey pubescence. Buds ovoid, with 

 outer scales ending in long points. Leaves scarcely flattened, but convex above and 

 below, keeled on the dorsal surface, with midrib prominent on the ventral green surface ; 

 radially arranged on the branchlets. 



SECTION II. 



LEAVES QUADRANGULAR WITH STOMATA ON ALL FOUR SIDES. 



I. Branchlets glabrous. , a 

 A. LEAVES OF LATERAL BRANCHES RADIALLY ARRANGED. 



P. Morinda, Link. Branchlets grey, pendulous. Buds large, ovoid, acute ; lower scales 

 keeled, cuspidate-acuminate. Leaves slender, l.J to 2 inches long. 



B. LEAVES OF LATERAL BRANCHLETS IN AN IMPERFECT RADIAL ARRANGEMENT. 



P. Schrenkiana, Fischer and Meyer. Branchlets grey, not pendulous. Buds dome-shaped ; 

 lower scales keeled, pointed, margins ciliate, not recurved. Leaves stiff, about an inch 

 long, with sharp cartilaginous points. 



P. pungent, Engelmann. Branchlets grey, not pendulous. Buds ellipsoid, with dry scarious 

 scales, margins recurved, not ciliate. Leaves stiff, J inch long, sharp pointed. 



P. polita. Carriere. Branchlets yellow, not pendulous. Buds dome-shaped, reddish brown, 

 shining ; lower scales ovate, acute, keeled. Leaves stiff and prickly, an inch long, falcate. 



C. LEAVES OF LATERAL BRANCHES, ON THE UPPER SIDE OF THE SHOOT MORE OR LESS 



IMBRICATE IN ARRANGEMENT, THOSE BELOW SPREADING LATERALLY IN TWO RANKS. 



P. alba, Link. Branchlets reddish brown or slightly glaucous. Buds ovoid ; lower scales 

 keeled, pointed, not scarious or ciliate. Leaves short, not more than \ inch long, often 

 curved, sometimes glaucous, disagreeable in odour when bruised. 



P. Alcockiana, Carriere. Branchlets whitish. Buds ovoid ; scales with ciliate margins, 

 lower ones acute and keeled. Leaves slender, about inch long, with two inconspicuous 

 bands of stomata each of two lines on the ventral surface, and five or six conspicuous 

 lines on the dorsal surface. 



1 In rare cases, broken lines of stomata are present on the ventral surface. 



2 In some specimens of Picca excelsa the shoots are quite glabrous. 



