48 UNIVERSITY OF COLORADO STUDIES 
Families and genera represented.—The 112 species of woody plants 
listed for the county are distributed in 29 families and 50 genera. ‘Trees 
occur only in the following families: Pinaceae, Juniperaceae, Salicaceae, 
Betulaceae, Ulmaceae, Pomaceae, Drupaceae, Aceraceae, Caprijoliaceae. 
Families represented by 7 or more species of woody plants: Pinaceae, 
Salicaceae, Grossulariaceae, Rosaceae, Pomaceae, Caprifoliaceae. Other 
families have only a few species each. It is of interest to point out that 
no oaks occur in the county although they are abundant at Morrison, to 
the south, and some occur in North Park, to the north. 
Other woody plants probably in the county.—This list is merely 
preliminary. More complete collections are necessary. Species should 
be looked for in the following genera: Juniperus, Sabina, Salix, Ribes, 
Rosu, Amelanchier, Prunus, Amorpha, Robinia, Acer, Ceanothus 
Lepargyraea, Phyllodoce, Cornus, Sambucus and Symphoricar pos. 
Economic plants.—Trees used for lumber: Pinus jlexilis, Pinus 
scopulorum, Pinus murrayana, Picea engelmanni, Pseudotsuga mucro- 
nata. ‘Trees furnishing posts and rails or used for fuel, in addition to 
the above list: Sabina scopulorum, all of the species of Populus and 
some of the willows. Trees planted for shade or ornament: nearly all 
the Pinaceae and Juniperaceae; all the poplars or cottonwoods, but 
more often Populus sargentii and Populus acuminata; some of the 
willows, also box elder. ‘Trees which are seldom planted but which 
might prove valuable for ornament: Betula andrewsii, Betula jonti- 
nalis, Celtis reticulata, Crataegus spp., Acer glabrum. Many of 
the native shrubs would be ornamental. Some of the following have 
been introduced to a slight degree but more might be used: Berberis 
aquifolium, Edwinia americana, Ribes longiflorum, Dasiphora fruti- 
cosa, Holodiscus dumosus, Opulaster monogynus, Opulaster ramaleyt, 
Rubus deliciosus, Rubus parviflorus, some of the species of Amelanchier, 
Sorbus scopulina, Ceanothus velutinus, Lepargyraea canadensis, Cornus 
stolonijera, A pocynum androsemaejolium, Distegia involucrata, Sambucus 
microbotrys. 
Geography of Boulder County.—The accompanying map gives the 
important streams and mountains as well as the towns in the county. 
East of the “front ridge of foothills” noted on the map there is plains 
