9 6 Morphology BOOK j 



with old traditional views which had been held to be 

 fundamental. It is strange that while we find him putting 

 forward these views, we meet in the same edition of the 

 Lehrbuch with the statement that the embryo-sac is the 

 representative of the ' macrospore ' of Selaginella, and the 

 nucleus (nucellus) of the ovule must be considered the 

 equivalent of the ' macrosporangium ' (Eng. Ed., i, p. 422). 

 The far-reaching importance of this recognition in the light 

 of morphology does not seem at that time to have impressed 

 him. Indeed it apparently escaped a proper appreciation 

 till Goebel promulgated the true morphological conception of 

 the sporangium. 



Other botanists were more conservative than Sachs. 

 The modified leaf theory was supported by Celakowsky in 

 1874 and 1877, and by Eichler in the second volume of the 

 Bluthendiagramme. On the other hand, Strasburger in 

 1872 appeared as an advocate of the older view of Schleiden 

 and Braun, and particularly opposed the idea that the 

 morphological value of the ovule can be different in 

 different cases. Making descent the foundation of mor- 

 phology he pointed out the uniformity of its construction, 

 wherever arising, and denied therefore that ovules can 

 have arisen at different times and in different ways. He 

 attributed to them the morphological value of a bud, the 

 nucellus being the axis and the integuments leaves. 



The supporters of the leaf theory denied the resemblance 

 to a bud on the ground that the development of the parts 

 of the latter is always acropetal, while the nucellus and 

 integuments arise basipetally. They supported their own 

 views by urging that the ovule as a leaf outgrowth becomes 

 homologous with the sporangium of a fern. Again we find 

 opinion advancing in the direction of the sporangial theory. 



This view, which is the second of the two to which we 

 have alluded, while gradually taking shape did not assume 

 its true importance till Goebel's famous pronouncement in 



