TRILLIUM 197 



(d) The central pistil composed of: 



(1) The basal ovule-case (ovary). How many 

 angles has it? How many lobes? 



(2) The relatively long styles. How many? 

 Their inner surface is modified into 



(3) A stigma. Describe this stigmatic surface 

 as seen both with unaided eye and under 

 the low power. Usually, numerous pollen- 

 grains may be seen adhering to it. What 

 process has therefore taken place? 



(4) The ovary is thus seen to be, not simple, 

 but compound. It is composed of three 

 carpels, bearing ovules. Since the ovules 

 are megasporangia, what is the homology 

 of the carpels? 



Look up in the dictionary, and record at this point, 

 the derivation of the names of the various parts of 

 a flower, studied above. 



(a) It is important to note: (i) That the various 

 cycles are each composed of the same number 

 of parts; (2) that the parts of the various 

 cycles alternate with each other. 



(b) When the other organs of a flower are inserted 

 below the pistil they are said to be hypogynous. 

 Is this true of Trillium? 



(c) The more or less enlarged end of the stem (or, 

 in non-sessile forms, of the peduncle) on which 

 the organs of the flower are inserted, is the 

 receptacle. 



Make drawings as follows: 



(i) A sepal (X i); a petal (X i); a stamen (X 4) 

 (both dorsal and ventral views); an imagined 

 cross-section of an anther taken through the 



