161] ENGELMANN—REVISION OF THE GENUS PINUS, ETC. I 
Revision of the Genus Pinus, and Description of Pinus 
ELLIoTTII. 
By Dr. GrorGE ENGELMANN. 
No difficulty exists in the circumscription of the genus Pinus ; 
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 most 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 Ceméra on account 
of its “‘wingless” seeds; Link (Linn:ea, 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 Ceméra and Strodus, 
were by the form of this scale distinguished from the other Pines ; 
he retained the character of the “‘ large wingless” seeds, to sepa- 
rate by it Cemdra from Strodus, and Pinea from the other two- 
leaved pines which constituted his section Prmaster. Later 
writers did not add anything to our knowledge of the systematic 
relations of pines: Carritre (Coniféres, 1855) copied Endlicher, 
and Gordon (Pinetum, 1858) went back to the mere number of 
‘leaves to characterize the sections. Ten years later Parlatore 
(DeCand. Prod. 162, 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 Pixus in two sections, Przea with pyramidate and 
Cemébra with dimidiate apophyses. The subsections of his Prxea 
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. 
