ENGEI.MANN REVISION OB" THE GENUS PINUS, ETC. 



Revision of the Gemis Pinus, and Description ^ PiNUS 

 Elliottii. 



By Dr. Gkorge Engelmann. 



No difficulty exists in the circumscription of the genus Pimcs ; 

 floral unite with vegetative characters to establish it so firmly and 

 so plainly, that nobody fails to recognize the species belonging to 

 it. But when we come to analyze and to group the 60 or 70 spe- 

 cies of pines which are known to us, we find that they appear so 

 similar, that all attempts to arrange them satisfactorily have failed. 

 The m'ost obvious distinctive character was found in the number 

 of leaves in each bundle, and thus the sections of 2-leaved, 3- 

 leaved and 5-leaved pines were the only ones known to the older 

 botanists. Spach (Syst. veg. 1834) separated Cembra on account 

 of its "wingless" seeds; Link (Linnasa, 1841) relied on the num- 

 ber of leaves only, adding two sections, one with 2 or 3, the 

 other with 3 or 4 leaves in a sheath ; Endlicher (Synopsis, 1847) 

 was the first to point out the form of the cone-scales as an impor- 

 tant character, and his first two sections Cembra and Strobus^ 

 were b}' the form of this scale distinguished from the other Pines ; 

 he retained the character of the " large wingless" seeds, to sepa- 

 rate by it Cemb7-a from Strobiis, and Pijtea from the other two- 

 leaved pines which constituted his section Pinaster. Later 

 writers did not add an} thing to our knowledge of the systematic 

 relations of pines: Carriere (Coniferes, 1855) copied Endlicher, 

 and Gordon (Pinetum, 1S58) went back to the mere number of 

 leaves to characterize the sections. Ten years later Parlatore 

 (DeCand. Prod. 16^, 1868) followed Endlicher in adopting the 

 differences in the form of cone-scales as the most valuable char- 

 acter, and advanced a step further by discarding the proportion- 

 ate size of the seeds as of sectional value. He divided his 

 subgenus Pinus in two sections, Pinea with pyramidate and 

 Cembra with dimidiate apophyses. The subsections of his Pinea 

 were again based on the number of leaves, in twos, in threes, or 

 in fives in each bundle ; those with single leaves, with 2 or 3, 

 and those with 3, 4 or 5 leaves had to find their place as best 

 they could. 



