— 21 — 



tion of Mr. Alvah A. Eaton's valuable sets illustrating the genus 

 Equisetum we are familiar with the fact that Bquisetum hyemale 

 presents many different forms, the most prominent of which 

 might well be called species were they not connected with the 

 type by numberless intergrades. It is, therefore, the more sur- 

 prising to find this newly discovered form does not intergrade 

 with B. hyemale to any significant extent. I regard it as a dis- 

 tinct species and have tabulated some of the differences below in 

 comparison with specimens of B. hyemale from another locality 

 not two miles distant from the station for the new species. 



Diameter of Stem. 



In 32nds of an 



inch. 



345 



6 



7 



8 



9 



Av. 



8 1 E hyetficile 







000 



26 



35 



18 



3 



7 









18 36 4. 











O 



O 



4 







Length of Joints. 













Inches and 8ths. 





2 in. X 1 



234 



5 



6 



7 



3 



in 1 









2 12 14 



16 



18 



10 



2 



2 









000 























2345 



6 



7 4 in. 



1 a ^ 



4 



5 



6 



7 



Av. 



0000 











000 



















2^ 



1232 



1 



4 



7 10 5 



10 



4 



2 



4 



4% 







Grooves 



in Stem. 



















13 m is 



6 





8 





20 21 



73 E. hyemale : 







000 







O 















52 New Species 







1 8 9 



9 



M 



5 



3 



1 







22 23 



/ 



24 25 26 



27 



28 



20 



30 



Av. 







1 3 



9 19 10 



iS 



4 



6 



3 



26 







1 



000 



















16 



Thus it will be seen that not only are the averages for the 

 two species very far apart, but that the extremes of the one 

 actually leave off before those of the other begin. In diameter 

 of stem, there is a difference of three thirty-seconds of an inch 

 between the averages and while the maximum of the new species 

 touches five thirty-seconds, the minimum of the other only reaches 

 six thirty-seconds of an inch. Again, in the grooves of the stem, 

 the maximum of the new species lacks two of reaching the 



