144 BOTANICAL GAZETTE [FEBRUARY 
. 
Comparisons 
In its departure from the order of succession of floral parts as 
exemplified by Cnicus arvensis (1) and Silphium (7), namely, 
corolla, stamens, carpels, and calyx, D. sylvestris is not unique. 
Although not exactly agreeing with HaNNaAn’s (4) report for Galiuwm 
A parine and Valeriana officinalis, in which the order of succession 
of floral parts is petals, stamens, sepals, and carpels, it is in perfect 
accord with the account of Martin (6) for Aster and Solidago, 
who describes the calyx in those forms as arising somewhat earlier, 
in fact almost simultaneously with the stamens. On the other 
hand, HANNAH states that the sepals of Helianthus annuus appear 
TABLE I 
Genus Order of succession of floral parts peo 
Sambucus: 5 sini. Sepals | Petals Stamens Carpels 4 
CAT, 6 os Petals | Stamens | Sepals Carpels 4 
 Waleviamae, a8 ay. ¢ Petals | Stamens | Sepals Carpels 4 
DIBOACUAS 0.5 cans Petals | Stamens | Sepals almost simul-| Carpels | Figs.9- 
taneous with sta- 14, this 
mens paper 
Revue feb sx Petals Staminodia Carpels 5 
Solidago and Aster...| Petals | Stamens | Sepals almost simul-| Carpels 6 
taneous withstamens 
TS se ca Petals | Stamens | Carpels Pappus 7 
Helianthus. . ..| Petals | Stamens | Carpels and _ sepals 4 
_ simultaneous 
Cnitus 755 Petals | Stamens | Carpels Pappus I 
about the same time as the carpels. A perfect acropetal succession, 
namely, sepals, petals, stamens, and carpels, is reported by HANNAH 
for Sambucus canadensis, and also by KirKwoop (sg) for Fevillea 
cordifolia, etc. 
Table I shows the succession of floral parts of these genera, 
members of closely related families. 
It is seen that, at least so far as the forms in which the sepals are 
much reduced or modified are concerned, the order of succession 
of floral parts is uniform for petals and stamens only. Since 
the primordia of either sepals or carpels may be third in appearance 
or even simultaneous, it is evident that a more extensive study of 
epigyny is necessary before any safe conclusion can be reached. 
