4 
BOTANICAL INDEX. 
SENSITIVE FLO WEES. 
by c. h. baker, Philadelphia, pa. 
»HILE making a drawing from a tine plant of Opuntia vulgaris, July 2d. 
1877, from New Jersey, I observed that its stamens were very sensitive 
when touched. They are, as you will remember, arranged about the 
pistil in several concentric whorls to the number of three hundred and 
more, with anthers interwove — those in the outermost whorls being the 
longest and maturing first. When they are touched, struck, or bent, 
those so treated close quickly toward the pistil, the motion is communi- 
cated to others, and in a few seconds there may be fifty assembled in a 
circle round the pistil, with numerous anthers either in direct contact with or close 
above the six-cleft stigma. If a single filament in the outermost whorl is bent back- 
ward a little, it changes its position with such force as frequently to break its way 
through the inner whorls in moving toward the pistil ; sometimes it starts up a few 
others, so that in such cases only a small number close against the pistil, and a ring 
does not assemble, as before remarked. 
This sensitive action lias taken place in every flower that I have examined, and I 
have seen it produced, as was to have been expected, by the burrowing of an insect 
among the filaments close to the base of the pistil, — an indubitable illustration of the 
scope of insects as agents in fertilization, all the more interesting since, through the 
peculiar property of the plant itself, an actual transfer of pollen by the insect would 
seem to be unnecessary. 
In alluding to this, I desire to learn if this property is exhibited by the stamens of 
other prickley-pears in the south and south-west, which the circulation of the Index 
will doubtless soon satisfactorily determine. 
Oct. 15, 1878. 
GRO WING SMALL SEEDS. 
G. P., in “The Garden,” Oct. 27, 1877 : “Small seeds, such as those of Lobelia, 
Begonia, &c., occasionally present, especially to the amateur, considerable difficulty 
in inducing them to germinate. This arises from the fact that, while it does not do 
to cover such seeds with soil, a very small amount of surface dryness is sufficient, 
when the seeds are swelling, to destroy them altogether. Covering the pots with 
moss or sheets of glass is occasionally recommended; but both tend to draw up the 
seedlings, and not unfrequently cause them to damp off. Such being the case, I 
submit the following plan, with which I have been very successful in raising hybrid 
Begonias, whose seed is very small indeed. In most plant-houses may be found pots 
surfaced with a delicate growth of moss, varying from the condition of a green felt 
to fully developed moss. On this sow the seeds. The moss maintains a general 
moisture, while its fibres retain among them the tiny seeds and prevent them from 
being washed down into the soil and lost. A piece of turf (peat) kept close and 
moist under a bell-glass also answers the purpose, but air must be freely and judi- 
ciously admitted as soon as the seeds are up. Altogether I am of opinion that the 
best nidus for such seeds as I have named is a moss-surfaced pot; in proof of this I 
may say that I have numbers of seedling Begonias amongst the various mossy pots 
in my little plant-stove — some showing flower, and others not ten days old.” 
[ There is nothing in all our greenhouse experience that gives us so much anxiety 
and with which we are so completely discouraged, as in our efforts to grow the seed 
of Begonias, Calceolarias, and a few other varieties of plants that have such small 
seed — for the seed of the Begonia is as fine as dust. If we can utilize an unsightly 
pot of moss for this purpose, we shall feel as though we had learned something of 
great, benefit, and had taken a step forward in the art of propagating. — Ed. Index.] 
The “Gardener’s Monthly,” in its notice of the recent exhibition of the Pennsyl- 
vania Horticultural Society, says: “There was one exhibitor who deserves great 
praise for something really attractively new to an exhibiton, Mr. E. D. Sturtevant, 
of Bordentown, N. J., who made a display of Water Lilies, Nymph.-ea eccrulea, the 
light blue; the remarkably brilliant red N. dentata; and N. dentata Devonienses : and 
our o\Vn sweet white N. odorata. This pretty red, white and blue combination, 
floating with their glaucous green leaves in a little fountain made for them, was 
particularly attractive.” 
