Apogamy in Camptosorus rhizophyllus* 
ELIZABETH DorotHy Wuist BROWN 
(WITH PLATE 2) 
The life history of Camptosorus rhizophyllus (L.) Link, in both 
generations, has been studied in detail by Pickett.t An ecolog- 
ical study of the prothallia has also been published by the 
same author,f but no mention is made of observed cases of 
apogamy either in the field or in cultures. Neither has apogamy 
been recorded for this fern by any other investigator. 
The case of apogamy described in this paper occurred in a 
culture of the fern which had been made, along with cultures of 
other ferns, to determine if apogamy could be induced by the mod- 
ification of external conditions. 
MATERIAL 
Collections of the fertile fronds of Camptosorus rhizophyllus 
were made during the month of August from plants growing on 
the limestone cliffs of a glen in the vicinity of Ithaca, New York. 
They were allowed to dry by exposing the sealed envelopes, in 
which they had been placed in the field, to sunlight before an open 
window for about a week. For future use the envelopes were 
placed in a pasteboard box in the laboratory. 
Cultures were made by sowing the spores thickly on 26 c.c. 
of Knop’s full nutrient solution, to which had been added a drop 
ofal per cent. solution of ferric chloride, in small glass capsules. 
The formula of Knop’s solution is as follows: 
Ma a ea eee 0.25 xan 
CoINOps Foe Se ph ee Se ge a ey I.00 
POs a ea OOO es eee es 0.25 * 
Be cow ee we oa eA eae pe ot pee e a Re Oh ag 

* Contribution from the Osborn Botanical Laboratory. 
The development of the prothallium of Camptosorus rhizophyllus. Bot. Gaz. 
57: 228-238. pl. 12,77 +f.1-8. I914. 
“Some ecological adaptations of certain fern prothallia—Camptosorus rhizo- 
phyilus are Asplenium platyneuron Oakes. Amer. Jour. Bot. 1: 477~498. pl. 
49,50 +f.I-19. 1914. 
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