84 PERIOD III. 



n 



an approach to the cryptog-amic ancestor of all the 

 flowering plants may remind us how little likely it was 

 that the ideal plant of Wolff and Goethe, consisting- of 

 leaves, stem, and other vegetative org-ans, but without 

 true reproductive org-ans, should fully represent the type 

 from which the flowering- plants sprang. No plant so 

 complex as a fern could maintain itself indefinitely 

 without provision for the fertilisation of the ovum ; the 

 only known asexual plants are of low g-rade, and, it 

 may be, insufficiently understood. 



What substratum of plain truth underlies the doctrine 

 of the metamorphoses of plants? Botanists would 

 agree that all sporophylls, however modified, are homo- 

 logous or answerable parts. Carpels and stamens are 

 no doubt modified sporophylls. Petals are sometimes, 

 perhaps always, modified stamens, and therefore modified 

 sporophylls also. We must not call a sporophyll a leafy 

 for it contains a sporangium of independent origin, and 

 the sporangium is the more essential of the two. The 

 common origin of foliage-leaf, bract, perianth leaf, 

 sporophyll (apart from the sporangium), and seed-leaf 

 is unshaken. We may picture to ourselves a plant 

 clothed with nearly similar leaves, some of which either 

 bear sporangia or else lodge sporangia in their axils. 

 Part of such a primitive flowering plant might retain 

 its vegetative function and become a leafy shoot, while 

 another part, bearing crowded sporophylls, might yield 

 male, female, or mixed cones. From an ancestor thus 

 organised any flowering plant might be derived. But 

 the chief wonder of the theory of Metamorphoses — viz., 

 the derivation of stamen and pistil from mere foliage- 

 leaves — disappears. Anther and ovule take their real 

 origin from the sporangium, whose supporting leaf is 

 only an accessory. 



