28 



MORPHOLOGY OF ANGIOSPERilS 



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. 6. — Salix 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. (.^branching stamen, each anther with 

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

 berlain. 18 



megasporangia, and in some eases 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 ; a and then in 1869 for the species of Naias, by Magnus,' 

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

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

 ler in 1876. Eohrbach •"' discovered cauline microsporangia 

 in Typha; Goebel n (p. 353) states that they occur in the 

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

 was confirmed by Schaffner 1T in 1807. In 1807 Campbell 15 

 added to the list ZannicheUia, and in 1808 TJlaea. 18 In 1000 

 Lotsy 30 suggested that the curious stamen of Rhopalocnemis 

 phaUoidcs (Balanophoraceae) is an axial structure. 



