TRILLIUM RECUR VA TUM. 2 1 7 



While this is generally true throughout phanerogams, 

 there are cases in which the calyx becomes attractive, 

 and other cases in which the calyx and corolla have so 

 far lost their original functions that they neither attract 

 nor protect. 



In the blended carpels, forming the pistil which in- 

 closes the ovules, we have the characteristic feature of 

 angiosperms as distinguished from gymnosperms. In 

 Avena the ovule is adherent to the wall of the ovary, 

 but in Trillium it is distinct; the whole after fertilization 

 forming the fruit with its inclosed seeds. Each carpel is 

 an infolded leaf, bearing the ovules upon its edges 

 (see fig. 11). Each should normally, then, contain two 

 rows of ovules, corresponding to the right and left 

 margins of the leaf, as in fact is the case in Trillium. 

 These lines of attachment, the theoretical leaf margins, 

 are known as placentae. The upper part of the carpel- 

 lary leaf is generally modified to form a long or short 

 style, while the stigma is a surface formed of cells se- 

 creting a viscid fluid, and more or less modified for the 

 reception and retention of pollen. 8 



The nucellus is the part of the ovule to appear first, 

 followed by the inner and outer integuments in the order 

 named (basipctal). Concerning the homology of the 

 ovule there has been and still is much discussion, and the 

 student desiring to pursue the subject must look to its 

 extensive literature. 9 The anatropous ovule of Tril- 



8 For discussion of the pistil and carpel, and references to the litera- 

 ture of the subject, see Gray, Struct. Bot., pp. 166 (with footnotes), 259, 

 et seq. 



9 Gray, Struct. Bot., pp. 267, 282; Eichler, Bluthendiagramme, 

 part II, page xv; Warming, De 1'Ovule, Ann. Sci. Nat., ser. 6, v, p. 

 177 ; Van Tieghem. op. cit., ser. 5, xii, p. 312 ; Sachs, Text-book, 2nd 

 Eng. ed., pp. 492, 570, etc, 



