. The ecological relations of roots . tap are profusely covered with a fine growth of root-hairs. Althoughthis plant, when compared with most others, has an exceedingly well-developedabsorbing system, it does not compare favorably with the wonderfully exten-sive and excellently developed root system of Aletes. However, both are welladapted to get the water falling during the frequent mountain showers andthrive under conditions where most plants could not grow. The roots arealmost white in color and very spongy in texture. Eriogonum flavum.—^This plant is a subdominant in the gravel-slide com-m
. The ecological relations of roots . tap are profusely covered with a fine growth of root-hairs. Althoughthis plant, when compared with most others, has an exceedingly well-developedabsorbing system, it does not compare favorably with the wonderfully exten-sive and excellently developed root system of Aletes. However, both are welladapted to get the water falling during the frequent mountain showers andthrive under conditions where most plants could not grow. The roots arealmost white in color and very spongy in texture. Eriogonum flavum.—^This plant is a subdominant in the gravel-slide com-munity, its masses of yellow flowers making it very conspicuous in theautiminal aspect. The specimen had a strong woody tap-root 2 cm. indiameter which tapered within a length of 6 inches to only 3 mm. in it gave off 2 laterals each 2 mm. in width. These ran off laterally forabout 2 feet at a depth of 3 to 7 inches. An enormous number of smallerprofusely branched laterals arose, forming a dense absorbing network about. Fig. 36.—Eriogonum flavum. 88 THE ECOLOGICAL RELATIONS OF ROOTS. the plant for a radius of more than 18 inches. These were extraordinarilywell-branched and rebranched and were very dense. At 5 inches in depthanother large lateral occurred, and the root broke into 2 nearly equal parts at6 inches in depth. One of these ran off into the bank and slightly upward toa distance of 2 feet from the base of the crown, but it was really much ended 3 inches below the soil surface. This lateral, scarcely more than 1nam. in average diameter, gave off both short and long branches in a profusemanner, all being repeatedly branched into minute termini and densely coveredwith root-hairs. They also dipped upward to within 2 inches of the surfaceand downward to 8 or more inches, but were most abundant at 4 or 5 inches indepth. The other root at the fork ran out into the slope for over 5 feet at anaverage depth of 16 inches. The roots often run long distance
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