FLOWERS OF IMPA TIENS FULVA 161 



continuous layers of cells are found filled with the tannin secretion. It 

 is equally abundant in the floral parts. As soon as the bract can be 

 recognized the hx-podermal layer shows every cell filled with tannin. 

 As the sepals and petals arise they show similar hypodermal layers. 

 The hypodermal layer of the wall of the ovary is composed of an enlarged 

 zone of cells each filled with tannin (Fig. 34). As the ovules develop 

 their integuments, similar hypodermal layers appear, and the prominent 

 ridges on the seed have the cells filled with the secretion. Even in the 

 anther, in a circle around the connective these cells are prominent in 

 cross sections. Similarly, enlarged cells densely filled with needle 

 crystals are scattered throughout the stem, leaves and floral parts. 

 These appear in the sepals, in the petals, in the filaments and anther 

 walls, and even in the developing pollen (Fig. 11), also in the walls 

 of the ovary and in the integuments. 



IV. The Stamens in the chasmogamous Flower 



The stamens in the chasmogamous flower arise as five protuber- 

 ances in the manner described above. As these protuberances increase 

 in height, they increase in width to broad masses. Before the anther 

 lobes have been differentiated the upper parts of the filaments have be- 

 come greatly expanded. These expanded portions later come in con- 

 tact, and form a united whorl of stamens joined in the upper part of 

 the filaments but free below. The adjacent anther walls also fuse to 

 a greater or less extent. From the inner face of each stamen develops 

 a broad flap of tissue which extends inward above the pistil (Fig. 5). 

 These may represent ligules from the microsporophylls. These ligule- 

 like processes grow inward until they meet in the center. In the cen- 

 ter and on their edges, they become organically fused forming a roof 

 over the pistil. Generally no opening occurs in this roof. Occasionally, 

 however, the pistil may be found to have forced its way between the 

 ligular flaps and to project slightly above it. Gray (18) figures the parts 

 thus. Generally the roof seems to remain intact until the staminal 

 whorl drops from its position. 



The pollen arises in four tracts, and the four pollen sacs remain 

 for some time after the formation of the endothecium. Gradually 

 the intervening tissue between neighboring sacs is broken down, forming 

 the two pollen sacs of the mature anther. Gray states that the two 

 pollen sacs are sometimes confluent at the apex (18). By this time inter- 

 nal layers of the anther wall have disappeared except for crushed tags 

 adhering to the inside of the endothecium. Shortly before dehiscence 



