THE VASCULAR CRYPTOGAMS 35 



result which could only have been arrived at by a com- 

 parison with Cryptogams. We may sum up our inferences 

 as to the relations of the female organs in the two types 



thus : 



Selaginella. Gymnosperm. 



1. Ovuin = 1. Ovum. 



2. Archegonium = 2. Archegonium. 



3. Prothallus = 3. Endosperm. 



4. Megaspore = 4. Embryo-sac. 



5. Megasporangium = 5. Nucellus of ovule. 



If we try to carry this comparison further, and to find 

 the equivalent in the Cryptogam of the carpels and 

 stamens of the Flowering Plant, we meet with some 

 difficulty. In Selaginella neither kind of sporangium is 

 borne actually on a leaf, but in its axil. Similar cases, 

 however, are known among Flowering Plants. We may 

 regard the leaves, in the axils of which the sporangia 

 of Selaginella are situated, as representing stamens or 

 carpels, according as the adjoining sporangium is a 

 micro- or megasporangium. There is, however, no 

 difl'erentiation between carpels and stamens in Selaginella 

 or in any Cryptogam. We may compare the whole spike 

 of Selaginella to a hermaphrodite l flower with no perianth, 

 and with stamens and carpels resembling each other. 

 In some Gymnosperrns also, as in certain members of the 

 family Cycadese, 2 the stamens and carpels are just alike 

 in their vegetative parts. 



1 Flowers are called hermaphrodite when, as in those of the Wallflower and 

 the Liiy, the stamens and carpels are both contained in the same flower. 



2 As the Cycadese have been referred to more than once, it may be worth 

 while to mention that they are a family of Gymnosperiha, of great 

 geological antiquity, now represented by a few tropical genera, with a 

 palm-like habit. They all have pinnate leaves of great size. The 

 student will find a magnificent collection of living Cycadeae in the Palm- 

 house at Ke\v. 



