Mac Doug al. — Symbiotic Saprophytism . 33 
established in the light of all known facts, though many points 
remain to be explained. 
The work of the writer upon Pterospora was carried on 
in the field in the Rocky Mountains from Idaho to Arizona, 
and upon alcohol- and herbarium-material obtained from 
numerous points in its range. 
Pterospora is furnished with an ovoid mass of dark brown 
club-shaped roots which ramify densely through a space 
of not more than 1 50 to 200 cc., in which the roots occupy 
a much greater proportion of the volume than the included 
humus. A heavy cylindrical shoot arising from this com- 
paratively small mass of roots attains a height of 50 to 
150 cm., and bears a profuse raceme of pendulous flowers. 
The stem is smaller at the base, swelling a few centimeters 
above to a thickness nearly double that of the base, then 
tapering to the apex. Glandular, fringed, oblong-lanceolate 
scales, 1 to 1 cm. long, are found on the lower part of the 
stem, decreasing as they ascend until they form but minute 
bracts subtending the pedicels. The stems bear elongated 
septate hairs and stalked glands, the latter affording a sticky 
secretion that renders the plant extremely viscid to the 
touch, and causes the adherence of spores, of its own 
seeds, and of organisms from the atmospheric plankton and 
even fragments of leaves and flowers. The entire plant is 
reddish or purplish-brown from the presence of an anthocyan 
or some tannin-derivative in the epidermal system. The 
colouring-substance is a pale eosin-red in alcoholic solution. 
The examination of such a solution which had been made 
in the field a month before, failed to show any distinct 
absorption-bands, a fact which does not preclude a possible 
relation to light useful to the plant. The sap has a decidedly 
astringent quality. Some of the clumps examined showed 
two or three stumps of old stems, and others having one 
or two living shoots exhibited two or three buds. From the 
general aspect of the clumps it seems reasonable to conclude 
that the plant has a somewhat protracted existence as a seed- 
ling, slowly developing the small compact mass of roots, 
