77 



The Ideal Ovary. 



The typical flower was held, not so very long ago, to have 

 four successive alternating whorls, of sepals, petals, stamens and 

 carpels. In the Structural Botany (1879, p, 177) Gray cautiously 

 concludes that the ''typical flower in nature has two series of sta- 

 mens, as it has two series in the perianth." For some years past 

 I have also believed in two whorls of carpels as essential to the 

 true conception of the typical flower, but have hesitated to ad- 

 vance this view lest it should be deemed too theoretical Now I 

 am gratified to find, in the Origin of Floral Structures (1888, p. 

 4), Prof. Henslow's typical flower represented as having *'two 

 whorls of carpels forming the gyncecium." Moreover, that 

 shrewd botanical thinker, Robert Brown, is cited as having come 

 to the same conclusion. Brown's reasons are not given. Prof. 

 Henslow seems to have been mainly influenced by observing that 

 the carpels are sometimes anteposed to the sepals and sometimes 

 to the petals, an incongruity most easily explained by assumin 

 two whorls, of which either one may be suppressed. I reached a 

 Hke conclusion by quite another road, namely, by observation of 

 the structure of the common orange. Excludins^ the external 



or 



. ^.. ^-^wi^^.w^ 



rmd altogether this fruit presents a series of complete closed, thin- 

 walled carpels, readily susceptible ofsepticidal separation. The 

 rind appears wholly extraneous and accessory to these, and it oc- 

 cured to me that the structure could be most plausibly and 

 perfectly explained by assuming an outer whorl of barren carpels, 

 united by their edges in the fashion of a polycarpellary one-cell- 

 ed ovary, and degraded to form a mere envelope for the normal 

 seminiferous carpels within. Under this view these outer carpels 

 are closely analogous to staminodia, being sexual organs in origin 

 and position but stripped of their normal function. Apropos of 

 the orange I may add here the observation that the stalked, elon- 

 gated, juice-filled cells of the pulp, springing from the inner surface 

 of the carpellary leaf, are true trichomes in structure and position, 

 and therefore, when we revel in the fruit of Citrus Aiirantinm, we 

 are, morphologically speaking, simply eating hairs ! 



E. E. Sterns. 



