322 FOKEST TEEES OF THE PACIFIC SLOPE. 



yon from Ruths Ranch Pass to Bullards Bar. thence eastward up Willow Creek to Camp- 

 tonville and beyond to at least 4,000 feet elevation (with western yellow pine). Sierra 

 County: Entered from west (on road Camptonville to Mountain House), and probably 

 also on canyons of North and Middle Forks Yuba River. Placer County: About 4 miles 

 northeast of Forest Hill (road to Sugar Pine Mill), Q. densiflora echinoides occurs in con- 

 siderable numbers. Stanislaus National Forest, locally abundant only between 3,000 and 

 5,000 feet, on west slope of Tunnel Hill, on headwaters of Alton Creek, Pilot Creek, near 

 Deep and Mutton canyons, and on Big Iowa Canyon (tributary South Fork American 

 River). Infrequent near southern limit in southern coast ranges, except in Santa Lucia 

 Mountains of Monterey National Forest, here extending from sea level to 5,000 feet in 

 watersheds of Sur, Carmelo, Arroyo Seco, San Antonio, and Nacimiento rivers ; most 

 important tree on streams flowing into the ocean, as it is also, but smaller in growth, of 

 higher elevations. Not about Monterey, nor on Monterey Peninsula ; few trees noted in 

 Arroyo Seco River canyon west of Santa Lucia Peak, and in upper part of Arroyo Seco 

 Valley above junction of Willow Creek ; commoner in gulches and canyons of coast slope 

 in Sur River region, and in isolated patches and groves of redwoods south of Carmel Bay. 

 San Benito County: Canyon (few hundred feet below summit) on north side of Fremont 

 Peak. San Luis Obispo National Forest, in basins of San Luis and Arroyo Grande rivers ; 

 locally noted near Cuesta Fass at 1,500 to 2,000 feet. Santa Barbara National Forest, 

 on watersheds of Santa Ynez, Santa Barbara, and Matilija rivers ; Mount Pinos at 9,500 

 feet ; summits of Santa Ynez Mountains, at 2,400 to 4,700 feet ; in T. 5 N., R. 21 W., some 

 distance northeast of Nordhoff ; also at head of Howard Creek, and of Horn Canyon (near 

 Nordhoff), which is probably its southern limit in the coast mountains. 



The variety Q. densiflora echinoides ranges from Canyon Creek (Siskiyou Mountains) 

 over northern California and southward in Sierras and coast ranges to Sonoma County ; 

 in Stanislaus National Forest, noted on north slope of Rubicon River, at 4,000 to 4,500 

 feet elevation. 



OCCURRENCE. 



Valleys and low slopes, borders of low mountain and foothill streams, coves, and 

 ravines ; in rich, moist, sandy, and gravelly soils. Sometimes in nearly pure, small 

 stands, but chiefly in mixture with redwood and Douglas fir ; occasionally with California 

 live oak. Largest in coast region. 



Climatic Conditions. — Similar to those of redwood. 



Tolerance. — Imperfectly known. Endures considerable shade throughout life, but 

 grows best with top light ; dense side shade clears its tall trunks completely. Gives evi- 

 dence sometimes of great tolerance. 



Reproduction.- — Prolific seeder and seedlings often abundant in partial shade. Sprouts 

 vigorously from cut stumps, producing permanent stems. 



Family TJLMACE-ffi. 



The elm family is composed maiuly of trees, with a few shrubs. It includes 

 the well-known elms and hackberries. Most of these have rather small leaves, 

 borne singly — never in pairs, one opposite another — and shed them each autumn. 

 Their flowers combine both male and female reproductive organs, though distinct 

 male or female flowers sometimes occur with the bisexual ones, on the same tree 

 or branch. Fruits are matured in one year, and are (1) small, flat bodies with 

 thin, papery wings (surrounding the seed body), which render them very buoy- 

 ant (elm) ; (2) small nut-like wingless bodies (planer-tree) ; (3) small, berry- 

 like bodies with thin, sweetish flesh surrounding hard, bony seeds, which are 

 eaten (without injuring the seed) by birds and mammals and so distributed 

 away from the parent trees (hackberries). The berry-like fruits ripen in 

 autumn, but the winged fruits, with few exceptions, ripen in spring or early 

 summer. The latter usually germinate that season, while the former do not 

 grow until the following season. 



The wood of these trees is characteristically marked with wavy or zig-zag lines 

 of minute pores, seen on cross-sections of the trunk. No other trees have this 

 character, which is particularly marked in the wood of the elms and hackberries, 

 the principal members of this family. 



Several members of the family are large forest trees of the first economic im- 

 portance, often forming the bulk of extensive forests, while others are scattered 



