32 
Colorado Experiment Station. 
Sample No. 11.—SOIL: clay loam, orchard. GROWTH: thick, dark 
blue-green scum covering 'the substratum and extending up the sides of 
flask; the growth on the quartz surface is tuberculate. ALGAE: Phormi- 
dium tenue, Nostoc “A”, Nostoc “B”, Nostoc commune. 
Sample No. 12.—SOIL: sandy loam, garden patch. GROWTH: un¬ 
fortunately this flask was broken before identifications of the algae were 
made; the plant mass extended completely over the substratum. 
Sample No. 13.—SOIL: clay loam, alfalfa field. GROWTH an ample 
development irregularly expanded, forming a thick coating on the sub¬ 
stratum. ALGAE: Phormidium valderianum, Nostoc “A”, Anabaena. “A”, 
Nodularia harveyana. 
Sample No. 14.—SOIL: clay loam, orchard. GROWTH: plant mass 
spreading on the quartz and sides of flask as a thick, dark-blue, gelatin¬ 
ous mass. ALGAE: Nostoc “A”, Anabaena “A”, Nodularia harveyana, 
Stigonema sp. 
Sample No. 15.—SOIL: sandy loam, orchard. GROWTH: abundant, 
blue-green, becoming yellowish-green due to the formation of gonidia. 
The minute dark green colonies between the quartz and sides of flask 
some distance below the surface are colonies of Nostoc “B”. ALGAE: 
Phormidium valderianum, Nostoc “B’\ Nostoc commune, Nodularia. 
harveyana. 
Sample No. 16.—SOIL: red. sandy loam, orchard. GROWTH: 
quartz, water surface and sides of flask grown over with a blue-green 
gelatinous scum, becoming rust colored. ALGAE: Phormidium tenue, 
Nostoc “B”, Nostoc commune, Nodularia harveyana, Rivularia “B”, Stig¬ 
onema “A”. 
Sample No. 17.— SOIL: raw soil, adobe hill. GROWTH: none. 
Sample No. 18.—SOIL: hard, gravelly clay, beet field. GROWTH: 
light, blue-green scum covering the quartz surface. ALGAE: Phormi¬ 
dium tenue. Anabaena “A”, Rivularia “A”, Stigonema sp. 
Sample No. 19.—SOIL: clay loam, beet field. GROWTH: about the 
second month after inoculation a slight green growth became evident, 
which later disappeared entirely. ALGAE: unicellular green alga. 
Sample No. 20.—SOIL: clay loam, orchard. GROWTH: plant mass 
forming a thick, gelatinous layer over the whole substratum. Several 
darker or olive green masses here and there prove to be Stigonema. AL¬ 
GAE: Nostoc “B”. Rivularia “A”, Stigonema sp. 
Sample No. 21.—SOIL: sandy loam, orchard. GROWTH: the algal 
growth in this flask is the most vigorous of all. The sand, surface of 
water and sides of glass on all sides up to the neck of the flask are coated 
with a thick, mucous layer which was at first bright blue-green, but later 
became pale blue-green. This abundant development is due largely to 
Nostoc “A”. ALGAE: Nostoc “A”. Nostoc “B”, Nodularia armorica, 
Nodularia harveyana, Stigonema sp. 
Sample No. 22.—SOIL: river bottom silt, truck patch. GROWTH: 
substratum grown over with a dark, brownish-green mass. ALGAE: 
Nodularia harveyana, Stigonema sp. 
It is difficult to see, from the limited number of samples ex¬ 
amined, any relation between soil type and abundance of algal de¬ 
velopment. Algae were found to be present in a variety of soils, 
for example, sandy loam, clay loam, heavy clay, hard, gravelly 
clay, heavy adobe and river bottom silt. While in samples Nos. 
8 and 19, a clay loam, there was slight growth, in samples Nos. 6, 
u, 13, 14, and 20, all of similar kind of soil, the development was 
vigorous, in most) instances totally covering the substratum in the 
