FLOWI'RS OF IMPA TIEXS FULVA 157 



to arise is the bract (Fig. 1 A, Fig. 7 A). A little later the two lateral 

 sepals appear (Fig. 2). Next the posterior saccate and then the anterior 

 sepal (Fig. 3). Figure 7 is a longitudinal section of a cleistogamous 

 flower, but the relation of parts here shown is exactly the same as in the 

 chasmogamous flower. Miss Riatt's Fig. 1 A is a longitudinal section 

 of a stage slightly older than the older stage of Fig. 7. The member 

 she marks saccate sepal looks very much like the section of the bract. 

 The lateral sepals would not appear in this section. The transverse 

 sections (Figs. 1, 2 and 3) show the relation of the bract and sepals. 

 Payer's account of Inipatiens Royleana agrees with the above account 

 oi fulva. The petals appear as two prominences inside the sepals (Fig. 



4 E). These are the posterior lobes. A little later the anterior lobes 

 arise (Fig. 6). For a time these prominences arise separately; later 

 they join in pairs, and each prominence then rises to form the single 

 claw of a two-lobed petal. The stamens appear about the same time 

 (Fig. 4 F and Fig. 8 C). At first the stamens are entirely free, and 

 at a later stage they become joined in their anther wall and filaments. 

 Three papillae inside of the stamens mark the developing pistil (Fig, 



5 A). The pistil is still quite open when the ovules are well advanced, 

 and it never entirely closes, stylar canals remaining open to receive the 

 pollen tubes. The stylar canals are formed here not by bieaking down 

 of tissue, but through failure of the pistil to entirely close over or fuse. 

 Figure 33 shows pollen tubes passing through the stylar canals in a 

 cleistogamous flower. This figure, except for the anthers and calyx 

 above, would serve equally well for the chasmogamous flower. The 

 placenta arises from the floor of the carpellary cavity, and the septa 

 push inward from the carpellary walls to meet the placenta (Fig. 6). 

 The placenta would thus seem to be axial in origin, and the ovules arising 

 upon it, cauline ovules. 



Morphology of Petals and Sepals in the chasmogamous Flower 



At one time there was considerable controversy as to the morphology 

 of the petals and sepals in the genus Impatiens. Payer (37) summed up 

 the various views up to his time. Jussieu had attributed to the flower of 

 Impatiens balsamina two small lateral sepals, and four petals of which 

 the inferior was spurred, the superior hooded and the two lateral deeply 

 bilobed. Richard viewed the flower as having four sepals — two small 

 lateral, one spurred inferior, and one superior — and four petals which 

 had become joined in pairs. Knuth viewed the calyx as composed of 

 the two small lateral sepals, of a spurred inferior sepal and a superior 



