194 THE STBUCTURE OF FLOWERS. 



nalis, Amsinckia angiistifolia, Statice psilocladia and Plantago 

 Coronopus, etc. 



The remarkable delay in the progress of the development 

 of the corolla during the emergence and first stages of 

 development of the stamens is the peculiar feature. It 

 sometimes allows the stamens to emerge first, as in Primula ; 

 or if they be nearly simultaneous, then the corolla may be 

 suddenly checked, as in Veronica. But many differences 

 occur ; thus they emerge and grow up together in Samolus, 

 while in Ancliusa officinalis the corolla rapidly exceeds both 

 stamens and pistil. In the case of Amsinckia the corolla 

 and stamens appear to emerge almost together, and then 

 follows the pistil, which the former quickly exceed in height. 

 Then the pistil regains the height of the stamens, and they 

 ultimately mature together. A similar procedure obtains 

 with Plantago Coronopus : though the petals emerge first, 

 the anthers quickly outstrip them, and the corolla grows 

 considerably more than the pistil, which is consequently 

 delayed ; but when they are nearly developed and the corolla 

 becomes scarious, then the style elongates with great rapidity, 

 and the stigmas mature first, so that the flower is ultimately 

 protogjnous. Exactly the same course is followed by the 

 floral whorls of Statice psilocladia. 



The next order of development is Calyx (if present), 

 Corolla, Stamens, Pistil ; or even Corolla, Calyx, Stamens, 

 Pistil. The cause of the corolla developing so soon is the 

 arrest of the calyx, as in Umhelliferm, Valerianece, and Com- 

 positce. The corolla now has to act as a protecting organ, and 

 always keeps in advance of the essential organs. Indeed, in 

 the orders with epigynous and gamopetalous corollas, in which 

 the calyx is usually obsolete or nearly so, the corolla actually 

 emerges before it. 



The last order of development to be mentioned in the case 



