ENGELMANN — PINUS ARISTATA, ETC. 207 



so much relied on, is of secondary consideration, and is often 

 calculated to mislead, separating the most natural affinities, 

 such as our Cemboid Nut-pines with 1-5 leaves, or the Pine- 

 oid Pines (P. JPinea, JP. Sabiniana, P. Torreyand) with 2-5 

 leaves. P. si/lvestris has an oval ament 3 1. long, with an 

 involucrum of 3 equal lance-linear acute scales in the axil of 

 a lanceolate recurved bract, which is deciduous with the 

 anient; anther with a short, nearly entire crista. P. Austri- 

 aca has a cylindric curved anient 1% inches long, with an in- 

 volucrum of about 10 very unequal and almost distichous 

 oval scales, in the axil of a linear-lanceolate recurved persist- 

 ent bract; anther, with a semicircular entire crista, large 

 enough to entirely hide the body of the anther in the yet 

 closed ament, ami give the latter the appearance of a young 

 cone. — Crista of the anther scarcely indicated by a knob, 

 smaller than in any pine examined by me. Female aments 

 single, or 2 together, near the end of the young shoot, brist- 

 ling with the lanceolate, aristate, erect scales, of purple-black 

 color. Cones oval, obtuse, 2^—12^ inches long, about half as 

 much in diameter, often covered with resin as if varnished ; 

 their purplish-brown or blackish color is found also in a little 

 group of alpine pines of the Popocatepetl with 3-5 leaves, 

 discovered by Roezl. Bracts, as in all pines, not obliterated 

 ("evanida3") as is usually stated, but much altered, and rather 

 indistinct ; more or less thickened and partly connate with 

 the base of the scale ; in our species, only the upper obtuse 

 mucronate part membranaceous and free ; scales 10-15 1. long 

 and 4-6 1. wide at their exposed part; transverse ridge of the 

 rhombic, rather flat, protuberance of the scale very conspicu- 

 ous; the slender mucro or awn, from the small rhombic 

 central knob, 2-3 1. long, curved upwards, at last tortuous and 

 easily broken oft", has suggested the name for the species. 

 Seed nearly 3 1. long, with the obovate wing 6-7 1. long ; em- 

 bryo in all the seeds examined by me with 7 short cotyle- 

 dons. 



Systematically, this species belongs to Endlicher's section 

 Pseudostrobits, which comprises many Mexican, some Cen- 

 tral American, and a single West Indian species ; it is its 

 only representative in the territory of the United States. 



EXPLANATION OF THE PLATES. 



PI. 5. Branches gathered about July 1st ; the upper one with stouter 

 leaves and half grown cones, about a year old, the young shoot of the 

 pre-ent year just pushing out, showing the scales variously broken, and 

 in their axils the tips of the young leaves. 



The lower branch, with more slender leaves, bears male flowers. 



PI. 6, Fig. 1, 2. Ripe cones — a smaller one closed and a larger one 

 with open scales; a, b, c, single scales from the side and upper surface, 

 ami seeds; these are incomplete, the only ones then seen by me; better 

 ones are figured PI. 11, Fig. 7 — a, external or upper; b, internal or lower 

 side. Fig. 8, embryo 10 times magn. 



