ENGELMANN— REVISION OF THE GENUS PINUS, ETC. I 75 



I now propose an arrangement of the species of Pbius based 

 upon the more essential characters above analyzed, and, though 

 I by no means claim it to be a faultless one, I expect that it will 

 deserve the character of a natural one as much as any that can 

 be devised. I find with Endlicher the most valuable character in 

 the fruit scale, or rather, to speak more correctly, I find that the 

 form of the fruit scale in this genus corresponds with a series of 

 other characters which constitute two very natural sections of the 

 genus. My section Strobiis in a wider sense includes his Strobus 

 and Cembra, and my Pinaster, also enlarged, comprises all his 

 other sections, viz. Pseudo-strobus, Tceda, Pinaster, and Pinea. 

 The subsections are distinguished by the position of the ducts 

 within the leaf, whether peripheral, parenchymatous, or internal. 

 Subordinate to this character is the subterminal or lateral position 

 of the female ament and the cone. Only after this may the num- 

 ber of leaves in a sheath be taken into consideration, and perhaps 

 the presence or absence of strengthening cells around the ducts. 

 It will be found that thus not only natural but to some extent 

 even geographical alliances are best preserved. I enumerate only 

 such species or subspecies (these in brackets) which 1 have been 

 able to examine myself; the list, however, will be found nearly 

 complete. The nomenclature of Parlatore in DC. Prod, xvi.- 

 is adopted unless otherwise stated. 



Sect. I. STROBUS. Apophysis with a marginal unarmed umbo, 

 generally thinner ; cones subterminal ; leaves in fives, their 

 sheaths loose and deciduous ; anthers terminating in a knob, or 

 a few teeth, or in a short incomplete crest; wood softer, lighter, 

 less resinous. 

 § I. EusTROBi. Ducts peripheral. — Northern or mountain species of 

 the Old and New World. 



* Wings longer than the seeds ; leaves sharply serrulate, denticu- 

 late at tip. 



t Strengthening cells few, none around ducts. 

 P. Sirobus, monticola^ excelsa, Peuce,^ parviflora^"^ Bonafartea,^ Ayaca- 



huite. 



ft Strengthening cells abundant under the epidermis and 



surrounding ducts. 

 P. Lambertia7ia. 



** Wings much shorter than seeds; leaves mostly entire, not 

 denticulate at tip. 

 P. Jlexilis, {albicaulis,) pygmcea. 



