RATTLESNAKE FERN AND ADDER'S-TONGUE. 43 



nate with double rows of sporangia along the midribs. 

 Occasionally a plant bears two. fertile spikes. The spores 

 are abundant, bright yellow, and escape from the cap- 

 sules through a narrow transverse slit. The blade is 

 noticeably thin and when dried is exceedingly delicate. 



The rootstock is scarcely discernible, the stipe seeming 

 to spring from a tangle of thick fleshy roots radiating 

 horizontally a few inches underground. Next year's leaf 

 bud is enclosed in a hollow in the side of the growing stipe 

 at base, and its tiny stipe encloses a still smaller bud which 

 in turn encloses another, the latter destined not to develop 

 for three years to come. According to Campbell's 

 " Mosses and Ferns," the development of the sporangia 

 begins fully a year before the spores are shed. 



Within our limits, this species never has more than a 

 single frond, except by accident, but in the West Indies 

 it normally appears with two. The author of the " Ferns 

 of Jamaica " remarks, " There are two fronds to each 

 plant, one without and the other with, the fertile division/' 

 The writer, who recently collected fine specimens in the 

 Blue Mountains of Jamaica, discovered, however, that 

 the fern is still true to its habit of producing but one 

 frond a year. The frond lacking the fertile division 

 proves to be the frond of the preceding year which the 

 mild climate allows to remain green until the next frond 

 is produced. The scar left by the withering of the fertile 

 spike is quite noticeable. 



Another peculiarity of this species is the great disparity 

 in size of fruiting plants and in the large proportion 

 of apparently full-grown specimens that are sterile. Some 

 bear fruit when but a few inches high, but others near by, 

 twice as large, do not. The cause of this sterility in the 

 large plants is unknown, unless it may be explained upon 



