258 DESCRIPTION OF SPECIES. 



MTRICACE^. 



Comptouia cuspid at a, sp. nov. 



Leaves long, linear or very gradually tapering upward to a terminal narrowly 

 elliptical lobe, pointed or apiculate by the excnrrent medial nerve ; pinnately lobed ; 

 lobes coriaceous, convex, subalternate, free at base, irregularly trapezoidal or obliquely 

 oblong, inclined upward and sharply acute or cuspidate; primary nerves, two or three 

 in the largest lobes, oblique, the upper curving in ascending to the acumen and branch- 

 ing outside, the lower parallel and curving along the boi-ders, anastomosing with 

 branches of the superior ones, generally separated by simple secondary short nerves. 



Comparable to Comptonia acutiloha, Brgl., and other European ter- 

 tiary species, but distinct from all by the larger cuspidata lobes turned 

 upward, &c. 



Hah. — Same as the preceding. 



Comptouia praeiiiissa, sp. nov. 



Leaves long, linear in their whole length, 5 to 10 centimeters long, 12 to 15 milli- 

 meters broad ; deeply equally pinnate-Iobate; lobes very obtuse or half round, cut to 

 the middle and slightly decurrent in their point of connection, the terminal very obtuse; 

 nervation obsolete ; substance somewhat thick, but not coriaceous. 



The species has its greatest affinity to the living Comptonia asplenifolia, 

 Ait. It also appears related to C. rotundata, Wat., as described by Schim- 

 per, " Pal. Veget.," ii, p. 555, a species known to me only by its description. 



Hah. — Chicknic Bay, Alaska. 



BETULACEtE. 



Betula alaskaua, sp. nov. 



Leaves small, round in outline, rounded or truncate at base, deeply obtusely den; 

 tate all around except at the base, turned back or recurved on a short petiole; medial 

 nervedistinct, the lateral obsolete; catkins short, cylindrical, oblong or slightly inflated 

 iu the middle, erect. 



Except that no glands are perceivable upon the stems, this species 

 agrees in all its characters with Betula glandtdosa, Michx., of Oregon. I 

 consider it as identical. 



Hah. — Chicknic Bay, Alaska. 



Alnus cor ylifolia, sp. nov. 



Leaves large, broadly ovate, rounded or cordate at base, acuminate or narrowly 

 oblong-ovate, doubly dentate on the borders ; primary teeth large, distant, more or less 



