144 Mr. Brown on some remarkable Deviations 



quires so complete and intimate a cohesion with the proper coat 

 of the seed as to be no longer either separable or distinguishable 

 from it. 



But systematic botanists have generally agreed to term a naked 

 seed not only this kind of fruit, but every monospermous pericar- 

 pium bearing a general resemblance to a seed, and whose outer 

 covering, though distinct from the nucleus, is only ruptured after 

 germination commences. 



For the purposes of an artificial arrangement this language may 

 perhaps be sufficiently accurate; but in determining the affini- 

 ties of plants, it is necessary to express by appropriate terms 

 those differences which are no less important than real. 



Of the fruits improperly called naked seeds, there are two prin- 

 cipal kinds : The first, in which the pericarpium is distinct from 

 the seed, is termed Akena by Richard in his excellent Analyse dii 

 Fruit; the second, in which the pericarpium coheres with the 

 seed, is the Caryopsis of the same author. 



An Akena (or Acheniian), even in a separate state, may in ge- 

 neral be readily determined. But it is not always equally easy to 

 distinguish a Caryopsis from a seed. It may indeed be done in 

 certain cases, as in Grasses, by attending to its surface, in which 

 two distinct and distant cicatrices are observable; the one indi- 

 cating the point of attachment to the parent plant, the other 

 that by which it was fcecundated. In certain other tribes, how- 

 ever, this criterion cannot be had recourse to, the surface of the 

 Caryopsis exhibiting but one areola or cicatrix, which includes 

 the closel}' approximated points of attachment and impregnation: 

 in such cases, the true nature of the fruit can only be determined 

 by its examination in an earlier stage. 



But although it must be admitted that an ovulum is never 

 produced without a covering, through some part of wliich it is 



impreg- 



