DUNCAN, ON THE TIGRIDIA. 13 
lst. The flower is very large, and therefore easily studied. 
2nd. The organs of generation are very distinct, and there 
s no fear of impregnation taking place before the expansion 
of the perianth.* 
3rd. The life of the flower is very short, and the passage of 
the pollen-tube down the long style very rapid. 
4th. The ovary is large, the impregnation of one of each 
pair of associated ovules very certain, and the facilities for 
‘making transverse sections are very great. 
5th. There are several flowers in each spathe; they bloom 
in succession, and the development of the ovule and the 
maturation of the seed may be studied in the same plant. 
IJ.—The flowers blow in July and August, opening at 
about 8 o’clock a.m., and the perianth closes and decays long 
before sunset. 
The stamens encircle the style for three inches and then 
become separate, and the style, suddenly losing its protect- 
ing tissue, issues forth to end in a triple termination. The 
anthers are large, and their opening is external. The ovary 
is large, inferior, and its apex is surmounted and surrounded 
by the origin of the combined stamens. The style, even at its 
entrance to the ovary, is thread-like, but is supported by the 
encircling filaments of the stamens. The tripartite stigma is 
covered with papillz, and has an oleaginous secretion. The 
remote end of the style is continuous with the tissues com- 
posing the axis of the ovary which supports the ovules, and 
whose tissues are to be traversed by the pollen-tubes. 
The ovary is divided into three cells ; each cell has its rows 
of ovules, and placentze, and is separated from its fellows by 
strong tissue. 
A transverse section of the ovary shows two ovules, side by 
side, in each of the cells (Pl. I, fig. 1); the ovules are attached 
to the central axis by the continuity of their vessels and 
general structure, and the micropyle (fig. 1, e) is external 
and touches the placenta (fig. 1, e). 
The placentary axis of the ovary is a very complicated 
affair; it has to give off vessels to three pairs of ovules, over and 
over again; moreover, it has to produce, under each micropyle, 
a papillary structuret (fig. 1, c), which is usually perforated by 
* Some imagine that impregnation occurs only in the perfect flower, but 
this is a mistake, and that it is so may be well proved in the Leguminose. 
{ This papillary structure cannot be the homologue of even part of the 
placenta; it is perforated by the pollen-tubes, and has nothing to do with 
the nutrition of the ovule. The whole of the nomenclature of the sexual 
parts of flowers has been complicated by the attempt tO recognise the 
