ECOLOGY OF SOME TROPICAL FERNS 



The following account of the adaptations of ferns to 

 their environment is condensed from an extended article 

 on " The Comparative Ecology of San Ramon Polypo- 

 diaceae," by Edward Bingham Copeland, published in 

 the Philippine Journal of Science for January, 1907. 

 The parts reprinted here are those which bear more di- 

 rectly upon the modifications which the ferns have 

 evolved to fit them for their places in the plant world. 



It has already been shown that large fronds are char- 

 acteristic of habitats having a moist air, and that, on 

 the other hand, large fronds, by virtue of their size, are 

 more or less xerophytic in their finer structure. Very 

 large fronds must have stout stipes and rhizomes which 

 are well anchored. The caudex of the huge rain-forest 

 variety of Aspidium tuzeanum is ten centimeters in diam- 

 eter. All our Dennstaedtias except D. Erythrorachis 

 have very stout prostrate rhizomes. The enormous 

 fronds of Angiopteris and Marattia spring from globose 

 caudexes which are often thirty centimeters in diameter. 

 Epiphytes have comparatively small fronds, the few ex- 

 ceptions being supported in an exceptional manner, 

 namely, Asplenium musaefolium, Polypodium heracleum 

 and Platy cerium j by massive nests which, in large speci- 

 mens, completely invest the supporting branch or trunk-, 

 as is sometimes the case with the stout rhizomes of Poly- 

 podium musaefolium, Drynaria quercifolia and Thayeria. 



The margins of large fronds are always reinforced to 

 give a protection against tearing. This protection may 

 be by marginal anastomoses of the veins, as in the case 

 of Asplenium phyllitidis; by walls merely thicker near 

 the margin, as in Cyclopeltis ; or by a more or less broad 

 and rigid cartilaginous border, as in the case of Hymen- 

 olepis and Acrostichum. When the margin is deflexed, 

 a very common occurrence, it is less likely to tear. If 

 the frond is lobed or incised, the sinuses are the places 



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