GREAT HORSETAIL. 109 



twelve and twenty teeth, and each is marked in the centre 

 by a prominent black rib. The cones are oval, and about an 

 inch or an inch and a half long. (Plate 1 15.) 



Sometimes fertile stems of greater length will be found 

 bearing branches. These it is the custom to regard as barren 

 fronds that have developed cones ; but, seeing that the 

 presence of the cone is the evidence of fertility, it is more 

 correct to speak of them as branched fertile stems. The 

 sheaths of these are intermediate in length and character 

 between those of the barren and the branchless fertile stems. 

 The spores are ripe in April. 



A cross section of the stem reveals a somewhat small central 

 tube, around which is a series of circular pores. A similar 

 series is near the external margin at the base of the ridges, and 

 between these two rows of circular pores are a number of 

 much larger kidney-shaped spaces corresponding with the 

 grooves on the stem (Plate no). 



The habitat of the Blunt-topped Horsetail is very different 

 from that of the Field Horsetail. The present species is a 

 marsh plant, and in addition to being a rare one, its distribution 

 is restricted to Scotland, Northern Ireland, and Northern 

 England, its southward range not extending below Yorkshire. 

 Its vertical range is up to 1200 feet above the sea. Its wider 

 distribution includes Europe, Siberia, and North America. 



Blunt-topped Horsetail is a book-name, but it has no other 

 in English. Pratense is Latin and relates to meadows. 



Great Horsetail (Equisetum maximum}* 



This is certainly the most imposing of the British Horsetails, 

 for the barren stems rise to a height of six feet or more though, 

 of course, not always or everywhere so tall clothed almost from 

 base to summit with whorls of long ascending and outward- 

 spreading slender, pale-green branches. There are about 



