28 



MORPHOLOGY OF ANGIOSPERMS 



willows, notably Salix petiolaris, in which Chamberlain 16 found 

 microsporangia in the " placenta " of the ovary, the carpel some- 

 times being wide open and bearing both microsporangia and 



FIG. Q.tSalix petiolaris. A, microsporangia in wall of ovary ; both anatropous and 

 orthotropous ovules. B, microsporangia with long stalks within the ovary ; pollen 

 normally developed ; ovule orthotropous. C, branching stamen, each anther with 

 four microsporangia; anther on right terminated by a stigma; x 50. After CHAM- 

 BERLAIN. 



megasporangia, and in some cases stigmas developing on sta- 

 mens (Fig. 6). 



The cauline origin of microsporangia seems to have been 

 recorded first in 1868 in the case of Casuarina, by Kauff- 

 mann ; 6 and then in 1869 for the species of Naias, by Magnus, 7 

 confirmed in 1897 by Campbell. 15 In 1873 Warming 8 made 

 a similar record for Cyclanthera, and was confirmed by Eng- 

 ler 9 in 1876. Rohrbach 5 discovered cauline microsporangia 

 in Typha-j Goebel 11 (p. 353) states that they occur in the 

 " unbranched stamens " ; and their occurrence in T. latifolia 

 was confirmed by Schaffner 17 in 1897. In 1897 Campbell 15 

 added to the list Z 'annichellia, and in 1898 Lilaea. 18 In 1900 

 Lotsy 30 suggested that the curious stamen of Rhopalocnemis 

 phalloides (Balanophoraceae) is an axial structure. 



