ECOLOGICAL ADAPTATIONS OF CERTAIN FERN PROTHALLIA 497 
LITERATURE CITED 
Campbell, D. H, Resistance of Drought by Liverworts. Torreya4: 81-86. 1904. 
Goebel, K. Organography of Plants. Eng. Ed. 1900, 1905. 
Irmscher, Edgar. Die Resistenz der Laubmoose gegen die Austrocknung und 
Kalte. Jahrb. wiss. Bot. 50: 387-449. 1912. 
Pickett, F. L., 1913. Resistance of the Prothallia of Camptosorus rhizophyllus to 
Desiccation. Bull. Torn Bot. Club 40: 641-645. 
, 1914. The development of the Prothallia of Camptosorus rhizophyllus. Bot. 
Gaz. 57: 228-238. 
Schroder, G. Uber die Austrocknungsfahigkeit der Pflanzen. Unters. Bot. Inst. 
Tubingen. 2: 1-53. 1886. 
DESCRIPTIONS OF PLATES XLIX AND L 
Plate XLIX 
With the exception of figs. 27 and 34 these photomicrographs were made with 
Zeiss 16 mm. apo. obj. and No. 4 comp. oc. The others were made with Leitz No. i 
achromatic obj. and oc. No. 2. Cramer's "slow Iso" plates were used. 
Asplenium platyneuron prothallia 
Figs. 20-22. Plants grown in full light, subjected to reduced light for sixteen 
days and then returned to full light. (X 75.) 
Fig. 23. Young plants subjected to reduced light. See fig. 3, 3a, 4. (X 75.) 
Fig. 24. Group of plants from culture of spores allowed to remain three weeks 
on distilled water in good light before Knop's solution was added. Photo taken ten 
days after the addition of nutrient solution. ( X 75.) 
Figs. 25, 26. Plants after a second change to reduced light. (X 75.) 
Fig. 27. Plants from a culture grown in weak light, showing zones of varying 
growth corresponding to periods of bright and dark weather. (X 40.) 
Fig. 28. Branched protonemal form. ( X 75.) 
Fig. 29. Plants subjected to a second period of reduced light. This with 21, 
22, and 26b shows attenuated outgrowths from older portions. (X 75.) 
Fig. 30. Plants showing uniform growth in light just too weak for normal 
development. (X 75.) 
Fig. 31 a-h. A group of plants from one culture, showing the great difference 
in response to variations of light intensity. (X 75.) 
Figs. 32, 33. Plants grown in full light and then placed in reduced light, showing 
attenuated branches from cells near the apical group. (X 150 and 75.) 
Fig. 34. Final formation of several plates by a branched form. Two other 
plates were attached at a and b but were torn away in mounting. (X 22.) 
Plate L 
Photomicrographs made with Leitz achromatic obj. No. i and oc. No. 2. 
Fig. 35. Asplenium platyneuron. A plant showing a pluricellular branch, a 
common form among mature plants of soil cultures changed from strong to reduced 
light. (X 52.) 
