—49— 



openings are directly connected with transpiration. The relative 

 size and position of these parts vary in different species, and are 

 in some the only sure means of determination. 



VARIETIES. 



As might be expected of plants of so wide a range, there are 

 many varieties, but rarely so well-marked that they might be 

 called sub-species, and many being simply forms or monstrosities. 

 A rvense has a dozen or more named varieties, Telmateia about 

 as many, as has hyemale and several others ; while ramosissi?num 

 has fifteen from Africa, and is accredited with a total of thirty- 

 four. 



WHAT IS MEANT BY "VARIETY." 



These notes, being intended to engender a systematic study 

 into this much neglected genus, rather than to set forth any pe- 

 culiar ideas held by the author, will adopt Milde's method and 

 give the name of every form. 



As the genus is small, this will not be cumbersome, and it 

 may incite investigation which will shed some light on the causes 

 of variation. The common idea of a "variety" is a well-charac- 

 terized, more or less constant race of a given species. The term 

 "sub-species" could best be used in that sense. As applied 

 herein, however, the term "variety" includes all forms and mon- 

 strosities of a species, without any claim that they are constant. 



WORLD DISTRIBUTION OF SOME EASTERN AMERICAN 



FERNS. 



LOOKING through Hooker's "Synopsis Filicum" recently, I 

 was interested in noting where our native ferns of the 

 eastern United States are found outside of our own country. 

 Cheilanthes lanosa ; Woodwardia areolata; Asplenium pinnatifi- 

 dum, ebenoides, angustifolium, montanum, and Bradleyi; Camp- 

 tosorus .hizophyllus ; Phegopteris hexagonoptera ; Dryoptens 

 acrostichoides, Noveboracensis, Goldieana, and marginalis; Cys- 

 topteris bulbifera ; Dicksonia punctilobula ; Trichomanes Petersii ; 

 Lygodium palmatum ; Schizaea pusilla , seem to be confined to our 

 own continent. Adiantum Capillus-Veneris, rare here, is well dis- 

 tributed through Europe, Africa, Asia, Japan, Polynesia and parts 

 of South America ; while A. pedatum is credited only to North 

 Hindostan, Japan, Manchuria and Alaska. Polypodium vulgare 

 is found throughout Europe to the Azores, Maderia, North Africa, 



