Eaton : Pterjdophvtes observed in Florida 463 



The southern plant shows a few fairly constant differences 

 from the northern. The petioles of the pinnae are woolly with 

 long, slender, tortuous and matted scales ; the secondary rachises 

 and mid-nerves of the pinnae are clothed with a similar though 

 usually shorter tomentum ; the pinnae are narrower, usually linear- 

 lanceolate, 4 to 5 times as long as broad, the veins very prominent, 

 and edges sharply serrate and indurated as though bounded by a 

 marginal vein. It is also different in aspect, the fronds being more 

 open and rather straggling. Specimens from Florida are very 

 similar to those from the West Indies, Mexico and Brazil, and 

 quite likely represent O. palustris Schrader. 



POLYPODIACEAE 



< ACROSTICHUM AUREUM L. 



On the east side this species was found only in the mangrove 

 swamp bordering the bay at Larkins. A low narrow beach has 

 been thrown up, so there is not a regular ebb and flow of the tide, 

 but the salt water enters during storms and the soil must be quite 

 salt. The plant grew in pools among the mangrove trees, mostly 

 in little openings, where there was a strong diffused light ; more 

 rarely in the sun. The whole floor of the swamp was flooded 

 and traversable only by stepping from root to root of the man- 

 groves, mostly 3 or 4 feet from the ground. Although less com- 

 mon than A. excelsum and confined to brackish swamps, A. aureum 

 has been supposed to be the only species of the genus in Florida. 

 It is a smaller plant than the other species, being mostly less than 

 2 meters high ; the stipes bear a few horny, black processes that 

 might be considered rudimentary pinnae ; the pinnae are farther 

 apart, the fruiting ones being confined to the top, usually only a 

 quarter or a third of each being fruited. The under surfaces of 

 the sterile fronds are naked save for a few minute dark scales, 

 mostly near the midrib; the basal areolations are elongated and 

 parallel with the midrib, the others oblique to it. It is a less 

 handsome plant than A. excelsum. The pinnae and rachis are 

 very brittle, the former being thinner than in A. excelsum. It is 

 the commoner species among the mangroves of the Ten Thous- 

 and Islands, always under the influence of salt water. 



