THE FLOWER 25 



matic surface is developed in various ways. This surface is 

 increased in area by the enlargement of the apex of the style, 

 by its branching, or by being developed laterally upon the style. 



One of the essential features of the structure of the carpel 

 is the provision for the progress of the pollen-tube from the 

 receptive surface to the sporangium or even to its micropyle. 

 A specialized and continuous nutritive tissue connects these 

 two extremes, often confused in the sporangial chamber with 

 the " placenta," in the style called " conducting tissue," and 

 upon its surface the " stigma," but forming one continuous 

 tissue system, well named the conducting tissue. It is unfor- 

 tunate that the terminology of taxonomy has somewhat di- 

 verted attention from the continuity of this tissue, for in it 

 the " stigma " is an organ distinct from the style, rather than 

 a display upon the surface, often modified to receive it, of a 

 special tissue of the style. While the placenta is the point or 

 line of sporangium origin, and may be said to consist of spo- 

 rangiogenic tissue, it is probably true that much of the out- 

 growth that stands for the placenta to many is conducting 

 tissue. In the case of hollow styles, as in Lilium, Butomus, 

 Agave, Erythronium, Viola, Campanula, Sarcodes, etc., the 

 conducting tissue lines the canal as a glandular layer, or in some 

 cases, as in Anagattis, fills up a hollow style; but in most cases 

 the style is solid, with the conducting tissue as an axial strand. 

 In case a single style is connected with two or more sporangial 

 chambers, the strand of conducting tissue branches into each 

 chamber. This suggests the possibility that the stylar canal, 

 with its lining of conducting tissue, may represent a primitive 

 angiospermous condition, and that the larger development of 

 this tissue has resulted in the prevailing solid style, a view that 

 is also suggested by the development of the style. Of course 

 the reverse may be true, and the stylar canal a result of the 

 breaking down or rupture of the axial strand of conducting 

 tissue. 



The strong tendency to a congenital development of carpels 

 has been previously noted, and this justifies the use of the term 

 " pistil " as one of convenience, although it does not stand for a 

 morphological unit. It is applied to any organization of car- 

 pels that appears as a single organ with one ovary, whether one 

 or more carpels are involved. It is to be noted that the term 



