396 XXIX. THE GYNCECIUM OF ANGIOSPERMS. 



of the pollen mother-cells into tetrads. For earlier examination 

 still, the Christmas Kose, H. niger, may be used. 



Tricarpellary Pistil. The ovary of Liliaceae is free, trilocular ; 

 we select at convenience the Tulip, Hyacinth, a Lily, or Hemero- 

 callis for examination. In the Tulip the three stigmatic lobes are 

 sessile upon the ovary, without style. In the Hyacinth the 

 style is short, the stigma small, slightly trifid. In Lilium the 

 style is long, the stigma tripartite. In Hemerocallis the style 

 is very long, the stigma likewise tripartite, but very small. 

 Cross-sections show us a trilocular ovary, composed of three 

 closed carpellary leaves which have grown together. Here, 

 neither outside nor in, is a limit between the tissues of the 

 individual carpellary leaves to be recognised ; and a single con- 

 tinuous epidermis covers the exterior of the whole structure. In 

 Yucca, another genus of the Liliaceae, the limits of the three 

 carpellary leaves are marked externally by grooves, and internally 

 by narrow radial pear-shaped cavities in the tissue each cavity 

 being lined by a distinct epidermis. Three carpellary leaves 

 therefore form in these cases a syncarpous, trilocular ovary. 

 Each of the three carpellary leaves combined into this trilocular 

 ovary bears, corresponding to its two edges, two rows of ovules ; 

 i.e., the placentas lie here in the inner angles of the loculi or cells 

 of the ovary. The placentation is therefore marginal, as in Del- 

 phinium ; but as they arise from the angles of the cells, and 

 therefore in the centre, it is specially designated axile placen- 

 tation. 



Structure of the Style and Stigma. Cross-sections through 

 the style of Hemerocallis show us in it a central triangular 

 passage the pollen-passage. Three vascular bundles are dis- 

 tributed at the three angles of the pollen-passage. A longitudinal 

 section through the apex of the style, and therefore through the 

 stigma also, shows us the surface of this latter grown out into 

 long papillae. This phenomenon is very general upon stigmatic 

 surfaces ; Hemerocallis, however, offers still another interesting 

 condition, in that the cuticle of the papillae is raised up by the 

 formation of slime or mucus. This cuticle is spirally striate, and, 

 in accordance with this, its upheaval follows a spiral line. At 

 length the cuticle is entirely loosened from the inner layer of 

 the membrane, and is exfoliated from the papillae. Other Lilia- 

 ceae, etc., likewise show a hollow style ; in most cases, on the 

 other hand, the style is solid, but filled either with cells easily 



