530 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



as has been described for so many plants, and the development is 

 one of steady progression. 



Within the innermost circle of stamens five small rounded 

 protuberances are formed. This last circle consists of the pri- 

 mordia of the five carpels or pistils. Each protuberance soon 

 becomes lobed as growth occurs in a circle that is not quite com- 

 plete, leaving a small groove. This is well expressed by Kraus^ (6) 

 as follows: "Directly after this very early beginning, growth does 

 not proceed equally in all directions from the center and form a 

 solid cone-like or spherical structure, but instead, about the 

 circumference of a circle which is not quite closed, thus forming as 

 further growth takes place, a narrow hood-like scale with infolded 

 edges." The five open or cleft pistil primordia are now found 

 with their openings toward the center or facing each other. The 

 cross section in plate 37, figure 2, shows the position of the 

 pistils and the narrow opening or groove leading into the enlarged 

 ovarian cavity of each pistil. A longitudinal section of this 

 stage is found in plate 37, figure i. The apices of the pistils 

 appear a little above the torus, which surrounds them. This 

 common tissue of the torus runs up the lengthening styles a short 

 distance, thus causing their apparent union, as shown in plate 39, 

 figure 3. The five free styles are shown in a cross section in 

 plate 38, figure 6. This section is made just below the origin 

 of the sepals and petals and shows the relative position of the 

 styles and stamens surrounded by the torus. Later development 

 of the pistils is shown in plate 38, figure 4. The simultaneous 

 development of the torus surrounding the pistils prevents the 

 identification of the pistil as a distinct structure except at the 

 inner surface, where a small indentation demarks one pistil from 

 another. The gradual development of the pistil is shown in 

 plate 35, FIGURES, 4 to 7, and plate 36, figures i and 2. The 

 openings of the pistils extend from the apex to the base, enlarging 

 at the base to form the ovarian cavity. The edges of the openings 

 become almost closed and upon these infolded edges or placentae 

 the ovules are produced. The five pistils are the last structures 

 developed by the torus and a very small portion of the end of 

 the axis remains. The five pistils become adjacent as growth 

 proceeds and the inturned edges form the boundary of a cone-like 



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