227 



our frontispiece shows, and appears to characterize in a 

 greater or less degree, all the plants of the gracillimum 

 type as they reach adult size. C. T. D. 



SOME POLYSTICHUMS; SPECIES AND 



VARIETIES. 



The genus Polystichuin, as regards species, constitutes a 

 very small, but interesting group of British evergreen 

 Ferns. The two or three species — for doctors differ — into 

 which this group is divided, fortunately for specialists, 

 abound in varieties of the most beautiful description. The 

 term Polystichiim, it may be as well to emphasize, is com- 

 pounded of two Greek words — polys, many, and stichos^ 

 order — which terms refer to the numerous and orderly array 

 of the lines of sori, which are so freely distributed over the 

 backs of the fronds. The common name. Shield Fern, has 

 reference to the round or shield-shaped indusia, which 

 cover the spore cases, and which have a central attachment. 

 The common name, however, is really a translation oiAspi- 

 dittm — another name for the genus — which is derived from 

 aspideon, a little shield. Hence we get Aspidistra, a favourite 

 room-plant, which is often grown in association with Ferns, 

 in fact, I have a pot in which some self-sown spores have 

 developed into nice little plants. Here the same etymo- 

 logical idea prevails with two distinct classes of plants. 

 If, however, I seem to lay stress on this fact, it is only 

 because a knowledge of the one is a great assistance to the 

 understanding of the other. 



Having thus disposed of some encumbrance, so to speak, 

 in regard to nomenclature, which I know is a stumbling 

 block to many, the most useful thing to do now is to 

 proceed to a description of varieties. But as varieties are 

 also subject to technicalities, I would like to point out that 

 common names are often misleading, whereas scientific 

 ones should spell accuracy, definition, and absolute identity. 

 Personally, I have respect for technical terms ; to me they 



