850 



PLANT STUDIES 



tlic body of the sporangium (Fig. 311, rZ), and was at first 

 not recognized as being a spore. 



These structures had also received names before they 

 were identified with tlie corresponding structures of tlie 

 loAyer groups. The megasporophyll was called a curpeh 

 the megasporangia ovules, and the megasporo an emhriio- 

 m(\ because the young embryo was observed to develop 

 within it (Fig. 310, em). 



The strobilus of megasporophyll s, therefore, may be 

 called the curpeUate strolUiis or citrpeJlatc cone. As the 

 carpel enters into the organization of a structure known as 

 the jiislil, to be described later, the cone is often called 

 the jiis/iUiite eane. As the staminate cone is sometimes 

 wrongly called a "male cone," so the carpellate cone is 

 wrongly called a "female cone," the 

 old idea being that the carpel with 

 its ovules represented the female sex 

 organ. 



The structure of the megasf)0- 

 rangium, or ovule, must be known. 

 The main body is the iivecllii.'< (Figs. 

 311, c, 313, iie)\ this sends out from 

 near its base an outer membrane 

 {hitejjmneiit) which is distinct above 

 (Figs. 311, h, 312, /), covering the main 

 jjart of the nucellus and projecting 

 beyond its apex as a prominent neck, 

 the passage through which to the apex 

 of the nucellus is called the mieropijle 

 ("little gate") (Fig. 311, a). Cen- 

 trally placed within the body of the 

 nucellus is the conspicuous cavity 

 called the embryo-sac (Fig. 311, d), 

 in reality tlie retained megaspore. 

 The rclatidus l)etween integument, mieropyle, nuecdlus, 

 and cnibryo-sac should be kept clearly in mind. In the 



Flo. 31], Dia!;i':iin c.f tlic 

 (■;iil)Cl structures of iiiiip, 

 sliow'iiii:^ the liravy scale 

 Ml wliir^li L.^nrs the 

 (i\'ille ( /,'), ill which ;ire 

 M'i'ii Ihe niiern]iyh- no, 

 iiile.jiiineni i/j), iiiici'lhis 

 In, eiiihrs'o sac or iiie^^a- 

 spiire !</).— Mc.iiKK. 



