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THE AM ERIC AX MUSEUM JOURNAL 



sinks have their sides eompletely cov- 

 ered with mats of iridescent filmy ferns 

 to the exclusion of all other vegetation, 

 while adjacent tree trunks and logs are 

 completely covered with another kind 

 of filmy fern. The filmy fern is com- 

 mon in tropical America. It was not 

 discovered in Florida until 1901. Some 

 species are found in dense hammocks, 

 ffrowing on trees and shruhs both near 

 the ground and high up, often covering 

 trunks and limbs with masses that can 

 be stripped off as mats several square 

 feet in size. In other sinks the small 

 halberd fern, the most abundant of the 

 fern species, predominates, while in still 

 others we find the honeycombed rock 

 sides adorned with various ferns, 

 filmies, maidenhair, halberd fern, Avood 

 fern, and spleenwort, not to mention 

 the rarer holly fern. 



The hammock floor is another kind 

 of fernery. There the strap fern, va- 

 rious wood ferns, maidenhair, spleen- 

 worts, sword fern, and large halberd 

 fern, comprise the most conspicuous 

 kinds. One species of wood fern 

 (Dryopteris ampla) is, at the same 

 time, the most conspicuous and the 

 most elegant. This is the largest of our 

 shield ferns and grows in small lime 

 sinks on the hammock floor. The erect 

 rootstock is commonly raised a foot or a 

 foot and a half above the surface of the 

 ground, thus forming a trunk which 

 supports a crown of beautifully arching 

 lacelike leaves with a spread of twelve 

 feet ! Thus, in habit it is a tree fern. 

 The large leaves separate readily from 

 the rootstock, and in parting retain a 

 dense tuft of brilliant red scales at the 

 base of the petiole. Still other varieties 

 of the shield fern prefer the hammock 

 floor to the lime sinks, and in the dense 

 jungle often grow very large. Leaves 

 eight feet long with slender narrow leaf- 

 lets are not unusual. A tangled mass 

 of these large plantsj covering from a 

 square rod to a quarter of an acre, is a 

 wonderful sight. 



In these remarkable hammocks there 



are ferns everywhere — ferns under- 

 ground, ferns on the ground, and ferns 

 in the air. The trunks and limbs of 

 rough-barked trees are actually clothed 

 with masses of ferns, as well as with 

 orchids and other air plants. The res- 

 urrection fern, the leaves of which 

 shrivel and curl up in dry weather, but 

 are restored to a perfectly fresh state 

 by a rainstorm, the strap fern with its 

 long narrow leaves, and the Boston 

 fern, are the most common epiphytic 

 kinds. The last mentioned has the dis- 

 tinction of having the longest leaves of 

 any of our ferns, a length of eighteen 

 feet being not uncommon, while the 

 maximum length is twenty-seven feet 

 and two inches. These long leaves 

 often clamber like vines over shrubs 

 and up tree trunks and hang over the 

 limbs of trees. The climbing fern oc- 

 curs plentifully in one hammock. Its 

 stems and branches adhere closely to 

 the stems of shrubs and trees, especially 

 to the smooth-barked kinds. Occasion- 

 ally it climbs up trees to the height of 

 twenty-five feet. Palmetto trees are 

 often conspicuous ferneries. Below the 

 crown of leaves and growing from 

 among the old leaf bases one often finds 

 a collection of Boston fern, grass fern, 

 hand fern, and serpent fern. 



One rather extraneous area comes 

 within our range, namely Eoyal Palm 

 Hammock. 1 This is an Everglade ham- 

 mock lying between the Biscayne pine- 

 land and the Long Key pineland. It 

 has a low rock floor, which is covered 

 with a foot or more of humus. Thus 

 far it is not known to have any ferns 

 that do not grow also in the hammocks 

 of the rest of our area. There are about 

 a dozen kinds of ferns common in its 

 jungle. 



The Florida Keys comprise two di- 

 visions of a chain of rock islands which 

 are really situated in the waters of the 



1 Known also as Paradise Key. Now within a 

 reservation with the official designation of Royal 

 Palm State Park. See Tropic Magazine. 4: 5-16, 

 1916. and Jovrnal of the New York Botanical 

 Garden, 17: 165-172, 1916. 



