25^ 



BOTANY OF THE LIVING PLANT 



The ovule at the period when it is ready for fertihsation is more or 

 less oval in form, and it is seated upon a stalk, the funiculus, which is 

 usually short (Fig. 206). It consists of a central body of conical form, 

 which is called- the nucellus. This is the actual mega- sporangium. It is 

 invested by one, and frequently by two integuments^ which are attached 

 to its base, and cover it closely, leaving only a very narrow channel 



Fig. 206. 

 Median longitudinal section of an ovule of Caltha, at the period of fertilisation. 

 /=funiculus. c/i=chalaza. o. m< = outer integument, i. w<=inner integument. 

 nMC = nucellus. w = microp}-le. e. a = egg-apparatus, ani = antipodals. /n = fusion 

 nucleus. ( x no.) 



open at the apex, which is called the micropyle. The opposite end, 

 where it is attached to the funiculus, is called the chalaza. A vascular 

 strand, springing from the vascular system of the carpel, traverses 

 the funiculus, but stops at the chalazal end of the nucellus. This 

 leads up the supplies to the base of the sporangium. The form of 

 the ovule varies. Sometimes it is straight, as in the Rhubarb or Dock 

 (Fig. 211) ; sometimes the body of the ovule is itself curved, as in 

 the Kidney bean or Shepherd's Purse. In -the great majority of cases 



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