194 THE REV. С. HENSLOW ОМ THE ORIGIN ОЕ FLORAL ASTIVATIONS. 
occurs frequently in the Crucifere when two stamens arise from the same quadrangular 
or oval gland instead of a single lateral опе ; but this is not that one has given rise to 
two, but that in addition to the normal one another is present. 
If, instead of regarding only the life-history of a plant per se, we regard it from an 
ancestral point of view, then ** cohesion," as of the gamopetalz, is the most correct term ; 
for it implies that the parts were originally (that is, in their ancestry) free, but are now, 
in the existing descendants, coherent; whereas *'inseparate " would imply that cohesion 
was an antecedent condition, and that there existed an ineffectual tendency to separate 
the parts of a whorl. 
That a cruciferous flower has arisen through insect agency I have no doubt, and 
strongly suspect that the lateral single stamens are specially concerned in intercrossing. 
On the other hand, there are several of our common cruciferous plants which are self- 
fertilizing, such as Capsella, Lepidium, and Senebiera. In some of these I have often 
deteeted the pollen-tubes penetrating the stigma even in unopened buds, as in winter. 
These I take to be degraded conditions. In these, too, as far as can be judged from the 
relative heights of the stamens and stigmas, it would seem that the four taller stamens 
are chiefly, if not solely, concerned in self-pollination. Іп Senebiero didyma it may be 
observed that there are but two stamens; and they represent the taller pairs, one for 
each pair respectively. This reduction is a condition not infrequent in inconspicuous 
self-fertilizing flowers; for the number of stamens is often reduced, as mentioned above, 
in the flowers of several of the Alsinee which do not require insect agency. 
X. Note B.—On Adoxa moschatellina. 
It may be interesting to some to have recorded the varieties which are found in the 
symmetry of the terminal as compared with the lateral blossoms. Of 71 heads of 
blossoms examined, all of which had the apical flower composed of whorls of fours, 
60 had all four flowers 5-merous below, | 
3 had two 4-merous and two 5-merous below, 
2 had three 5-merous and one 6-merous below, 
3 had three 5-merous and one 4-merous, 
1 had four 4-merous, 
1 had two 6-merous and two 5-merous, 
1 had the apical flower 5-merous, with three 6-merous and one 5-merous below. 
This plant is also remarkable for the order of expansion in the different parts. 
The terminal flower opens first ; and its parts expand all at once. Of the lower flowers 
the two upper sepals of a flower open out first ; then the two upper stamens are mature, 
and shed their pollen; next, the anthers below them dehisce in succession downwards. 
during which period the lower sepals begin to expand. 
DE Note С.—Ох THE ORIGIN OF THE TERNARY AND QUINARY SYMMETRY OF FLOWERS 
| WITH INDEFINITE AND SPIRALLY ARRANGED MEMBERS. 
: обрне the two genera comprising this order, both of which have Ор 
site leaves, Calycanthus illustrates an " гае from opposite leaves to the зг 
