212 THE ANBKCECILm OF MENTZELIA. 
are developed about the time of, or immediately after, the appearance 
of the stamens of the second degree. "Whatever may be the exact 
moment of the appearance of the cai^els, there can be no donbt that 
they appear long before the staminal evolution is completed. 
Paver describes the development of the andrcecium in Bartoiila as 
being essentially similar to that in Mentzelia, with this exception, that 
the five pnmary staminal mammillae, instead of being developed as 
stamens, assume a petaloid development, — whence the corolla of Bar- 
ionia is ordinarily described as consisting of ten petals. The number 
of stamens, however, is vei^ much greater than in Mentzelia anrea ; 
and it will be seen from the diagram (Pig. 2), which I have constructed 
in accordance with Payer's figures, that there are no stamens exactly 
intermediate between the primaiy ones (the false petals) before the 
sixth range. 
Having thus briefly detailed the principal phenomena connected 
with the staminal evolution in Mentzelia and Bartonia, I shall now 
proceed to consider what conclusions may be legitimately drawn there- 
from regarding the nature of the andrcecium in these plants. Payer's 
opinion, as I have already stated, was that this andrcecium consists of 
several staminal whorls. His idea was, no doubt, suggested by the 
definite and regular manner in which the several ranges of stamens 
succeed each .other on the inner surface of the receptacnlar cup. If, 
however, the andrcecium really consisted of a number of whorls, w^e 
shoul'd expect to find the carpels appear after the completion of the 
staminal evolution, and not before it. The fact that by far the greater 
number of the stamens appear after the carpels are developed, seems 
to me to constitute a fatal objection to Payer's theory. 
If the general disposition of the stamens be attended to, it will be 
obsei-vcd that the stamens of the first two or three ranges in Mentzelia, 
and of the first five in Bartonia, exhibit a distinct aiTangeraent into 
groups superposed to the sepals. If, again, it be borne in mind that 
in almost all polyadelphous plants the carpels appear before the evolu- 
tion of the stamens is completed, it cannot reasonably be doubted that 
w^e have here to do with five confluent compound stamens superposed 
to the sepals, with a centripetal evolution of lobes analogous to what 
Payer has described in the compound stamens of the MyrlacetB, 
Admitting the correctness of this interpretation of the andrcecium 
of Mentzelia and its allies, the question arises as to the nroorietv of 
