382 BOTANICAL GAZETTE [NOVEMBER 
SYMPHORICARPOS ASSOCIATION 
Y (12, pp. 127, 128); RoBBINs (16, p. 38). 
The Symphoricarpos association is best iad in moist, fine-grained 
soil; best seen, in the foothills, on basal or other deep-soiled detrital slopes, 
clay or loam, with or without humus. The common species of the Colorado 
foothills is Symphoricarpos occidentalis. The bushes are low, are spaced very 
close together, and are profusely branched, giving the whole growth a very 
compact and uniformly dense structure, especially where subject to grazing, as 
in many stations. From its habitat relations, the bush honeysuckle, as it may 
be called (it is known in some localities as buckbrush), adjoins a semi-meso- 
phytic grassland in most places, competing and alternating sharply with it. 
Many of the taller mesophytic herbs are seen at the border, including Frasera 
speciosa, Thermopsis divaricarpa, the others already mentioned as bordering 
canyon forest and mixed shrub, and frequently the tall grass Stipa viridula. 
This border condition is best seen where the Symphoricarpos assemblage 
occupies a depression. 
The shrub area is dominated by the one species, although bushes of Rosa 
arkansana are mixed in, abundantly in places, and Berberis aquifolia may also 
be seen. A few herbs may occur underneath. 
Symphoricarpos in places forms a border between mixed shrub or canyon 
forest vegetation and grassland. 
MESOPHYTIC GRASSLAND ASSOCIATION 
RAMALEY (12, p. 129), meadow formation. 
There are several kinds of herbaceous vegetation in the foothills, of meso- 
phytic or semi-mesophytic character, which may for convenience be considered 
together. There is a meadow growth, which shades more or less completely 
into the western prairie-grass of the mountain-front (24, p. 390), on the one 
hand, and into the forest border and forest undergrowth assemblages on the 
other. On certain shaded ravine slopes a mixture of mesophytic herbs from 
several of these assemblages has been observed, apparently independent of any 
tree canopy. The trees affect the herbs, apparently, mainly or wholly by their 
modification of physical conditions. A selected list of mesophytic and semi- 
mesophytic species may be given: 
MESOPHYTIC AND SEMI-MESOPHYTIC HERBS OF FOOTHILLS 
Stipa viridula (ch) Gentiana affinis 
Danthonia Parryi (f) Frasera speciosa (ch) 
Poa pratensis Mertensia ciliata 
‘oa Buckleyana Mertensia lanceola 
Agropyrum violaceum Monarda canner (ch) 
