TREE FERNS OF NORTH AMERICA MAXON. 491 



Plate 12. 



Segment of Hemitelia horrida, showing the ample, hood-shaped, laterally attached 

 indusia which protect the young sporangia. Specimen from the upper 

 slopes of the Gran Piedra, eastern Cuba, altitude about 3,000 feet, April 

 14, 1907, Maxon 4034. Eight times natural size. 



Plate 13. 



Fig. A. Alsophila blechnoides, the only American tree fern having more than one 

 sorus upon a veinlet. Specimen from hilly forest above Las Cascadas, 

 Canal Zone, Panama, altitude about 500 feet, February 19, 1911, Maxon 

 4887. 



B. Sori and indusia of Dicksonianavarrensis. Specimen from mountains 5 miles 



south of Cartago, Costa Rica, altitude 5,500 feet, May 12, 1906, Maxon 513. 



C. Sori and indusia of Culcita coniifolia. Specimen from humid forested slopes 



near Cerro de la Horqueta, western Chiriqui, Panama, altitude 6,500 feet, 

 March 18, 1911, Maxon 5459. 



D. Sori and indusia of Cibotium Schiedei. Specimen from Zacuapan, Vera 



Cruz, Mexico, November, 1908, Pur pus 1976a. 

 All at four times natural size. 



Plate 14. 



Section of a pinnae of Dichsonia navarrensis at natural size. Specimen from mountains 

 5 miles south of Cartago, Costa Rica, altitude 6,500 feet, May 12, 1906, 

 Maxon 513. 



Plate 15. 



Section of a pinna of Cibotium Schiedei at natural size. Specimen from Zacuapan, 

 Vera Cruz, Mexico, November, 1908, Purpus 1976a. 



