BOTANICAL SUBJECTS. 



223 



and has remained unselected. It has consequently altered very 

 little, excepting in size. 



"Who can tell how many of our present forms of plants, -with 

 all their details of character, have descended from distinct forms ? 

 We are always trying to refer the form of an organ to some one 

 typical form, as if we believed that there was any such 

 prototype. 



The anther of Gomphrena is one-celled, and may have 

 descended from the two adjacent clusters of spore-cases, like those 

 of Scolopendrium vulgare, Sm., in which the placentas of the 

 sporangia, from contiguity, have become confluent, the indusia 

 opening, like the edges of an anther in opposite directions. The 

 anther of the Mallow may be explained, either in the same way, 

 and by becoming a little twisted, or by descent from a plant which 

 had a bract-like indusium, such as Asplenium filix foemina, one 

 flap of the anther corresponding to the indusium, the other flap 

 corresponding to a contracted frondlet.* 



If, however, these likenesses seem unsatisfactory to the reader, 

 he has not far to search for an almost exact morphological 

 equivalent of the mallow anther ; in Lycopodium clavatum, Lin., 

 we have an exact copy of the mallow anther, in the bivalvular 

 indusium, only it is sessile. It is, moreover, located in the axilla 



Fig. 76. Two-valved capsule of Lycopoduim clavatum, including spores 

 (Hooker's " Br. Fems," pi. 49). 



* It is enough to glance through " Hooker's Brit. Ferns " to discover 

 numerous homologies. 



