— so— 



hybrid since its spores are abortive. It is most easily distinguished 

 from the common species by its sheaths which are loose and 

 flaring upwards., Other differences may be found in any botany. 



This brings us to the evergreen species. The commonest is 

 the true scouring rush (B. hyemale), found on river banks, moist 

 woods and similar places. Its tough stem endures great cold and 

 often the juices in the interior are frozen solid with no apparent 

 injury to the plant. The outer cuticle contains so much silica 

 that the vegetable parts of the stem may be eaten away with acids 

 leaving this glass-like skeleton in its place. It is much like the 

 river horsetail in superficial appearance, but it is much rougher 

 and stiffer, seldom if ever grows in water and rarely branches. 

 Bquisetum robustum is very much like the preceding species, but 

 as its name indicates, is larger and taller. It is a southern species 

 found from Ohio south and westward. Bquisetum laevigatum 

 differs from B. hyemale principally in being smaller with loose 

 sheaths enlarged upwards. It is much less common. The smallest 

 of the scouring rushes is Bquisetum scirpoides, which grows in 

 wet fields, on banks, etc. Its stems are short, slender and tufted 

 and easily overlooked. It fruits early and may be sought at the 

 time the field horsetail spikes are showing. Bquisetum variegatum 

 resembles this last, but is a more northern species. The minute 

 differences which separate them can be found in any good botany. 

 Both species are evergreen. 



Those who wish for further information about the Bquisetums 

 will find in addition to the instructive series of papers being pub- 

 lished by Mr. Eaton in this magazine, an article on Bquisetum 

 scirpoides in volume 6, page 25, and one on the field horsetail in 

 volume 7, page 31. From the latter the illustration in this article 

 is reprinted. — W . N. C. 



Iu connection with a note on Pelltza atropurpurea in the 

 January Bulletin, it might.be well to mention its former occur- 

 rence on the walls of an old iron furnace near Glen Burnie, Mary- 

 land. This locality is at least ten miles from any limestone and 

 equally far from any other known locality for the fern. Unfor- 

 tunately the plants were all destroyed by the tearing down of the 

 fnrnf^e. — C. E. Waters. 



