BROADLEAVED TREES OF YOSEMITE NATIONAL PARK 



tered. At maturity they are four or 

 five inches long and appear as grape- 

 like clusters of round, green globules, 

 each one containing a multitude of 

 tiny, brown seeds to which are at- 

 tached a number of soft, cottony fila- 

 ments by means of which the seeds 

 are wind dispersed. It is to this 

 character that the tree owes its name. 

 In midsummer when the green ssed- 

 laden capsules open, the air is filled 

 with these wind-borne seeds and the 

 ground in the vicinity of these trees 

 is often covered with a thick, downy 

 carpet of "cotton." 



The twigs are slender to moderately 

 stout, sometimes slightly angular, and 

 vary in color from orange-brown to 

 greenish-brown. The buds, similarly 

 colored, are as much as three-quar- 



ters of an inch long, narrowly conical 

 with six or seven overlapping scales, 

 but their most distinctive characteris- 

 tic is the presence of gummy, frag- 

 rant resin. Leaf scars which, with the 

 twigs and buds, assist in winter iden- 

 tification of this tree are large and 

 conspicuous, being slightly raised, 

 broadly crescent-shaped to triangu- 

 lar in outline (sometimes three-lobed), 

 and alternate, with three large vas- 

 cular bundle scars appearing there- 

 on. 



The natural range of the black Cot- 

 tonwood includes an extensive area 

 of the Pacific west — from southern 

 Alaska and the Yukon south through 

 British Columbia, Washington, cmd 

 Oregon to southern California. 



QUAKING ASPEN 

 Populus tremuloides Michx. — Willow Family (Salicaceae) 



As one of the most interesting trees 

 of the higher elevations in the park, 

 the aspen is rendered conspicuous 

 by the character of its bark, which is 

 generally smooth and white, and the 

 habit of the leaves quivering in the 

 slightest breeze. 



Park visitors who remain on the 

 Valley floor will not have the pleas- 

 ure of observing the graceful beauty 

 of this tree for it is found in the Cana- 

 dian and Hudsonian Zones, rarely 

 growing below 5,000 feet. It will be 

 most readily noted along the Tioga 

 Road in the vicinity of Yosemite 

 Creek, on the Glacier Point Road near 

 Bridalveil Creek or in the vicinity of 

 Badger Pass, along the trail between 



Nevada Falls and Merced Lake, 

 about Washburn Lake, and between 

 Glen Aulin and Waterwheel Falls. 

 Aspen Valley owes its name to the 

 groves of this species in that area. 



Although generally smooth and 

 white (sometimes with a cream-col- 

 ored or light green cast), the bark is 

 often marked with numerous black, 

 wart-like protuberances. On older 

 trees it is generally rough and dark 

 brown at the base. The slender limbs 

 are irregularly bent and stand out 

 straight from the trunk. Where aspens 

 are found in the open the limbs form 

 a loose, narrow, dome-like crown that 

 extends throughout most of the tree's 

 height. However, the aspen is very 



