470 DR. M. T. MASTERS ON THE SUPERPOSED 



6. Interposition. — In some of the cases last mentioned, as in 

 Rhododendron and its allies, in Greraniales, Dictamnus, Acer, 

 &c, subsequent to the formation of the primary stamens a se- 

 condary production of stamens is observed to take place. Some- 

 times these secondary stamens are in equal number with those 

 first developed ; at other times they are fewer in number. In 

 the last instance it frequently happens that a stamen gets placed 

 in front of a petal. The proper relative position of the carpels 

 remains unaffected in most of these cases. Although much 

 stress was laid on this phenomenon of interposition by Payer, whose 

 views have been adopted by Sachs and others, yet it is a question 

 whether some of these cases, e. g. in Greraniales, are not better ex- 

 plained on the supposition that the new growths are subdivisions 

 of the primary stamen, as in Malvaceae or Hypericum. See also 

 the diagram of Styrax in Le Maout and Decaisne's Gen. Syst. 

 ed. Hooker, p. 451, with its single row of isolated stamens, twice the 

 number of the petals, and compare this with the figure of Symplocos 

 with its branched stamens. By Chatin and Eichler* plants with 

 a double androecium, the outer whorl of which is superposed to the 

 petals, are styled " obdiplostemones." The outer stamens in these 

 cases are regarded as outgrowths from the petals or as interca- 

 lated elements. Chatin further explains some of these instances 

 by showing that while in the adult flower the stamens are in one 

 row, in the young state they are in two. 



7. Substitution of one organ for another. — The diagram for the 



Xc 



to the five sepals, thus — 



8 5 



5. 



In the male flower, according to the diagram in Le Maout and 



Decaisne's < General System of Botany,' ed. Hooker, p. 324, tbe 



arrangement is 



S5 



i 



P5 



St 5 



X. 



It would seem, therefore, in this case as if the stamens in the 

 female flowers were really replaced by carpels, the latter occupy- 



* Eichler, « Bluthendiagramme ' (1875), p. 187; Chatin, ' Comptes Rendus,' 

 1856, p. 13, ex Eichler, I. c. 



