Our three illustrative examples are good and permanent races, producing
their peculiar qualities [372] regularly and abundantly. In this respect
they are however very variable and dependent on external circumstances.
Such a regularity is not met with in other instances. Often
pedigree-experiments lead to poor races, betraying their tendency to
deviate only from time to time and in rare cases. Such instances
constitute what we have called in a former lecture, "half races," and
their occurrence indicates that the casual observation of an anomaly is
not in itself adequate to give an opinion as to the chance of repetition
in sowing experiments. A large number of species seem to belong to this
case, and their names may be found in the above mentioned work by
Masters and elsewhere. But no effort has yet been made to separate
thoroughly the pistilloid half-races from the corresponding
ever-sporting varieties. Some plants are recorded as being more liable
to this peculiarity than others.
Stamens are sometimes replaced by open carpels with naked ovules arising
from their edges and even from their whole inner surfaces. This may be
seen in distinct strains of the cultivated bulbous Begonia, and more
rarely in primroses. Here the apex of the carpellary leaf is sometimes
drawn out into a long style, terminated by a flattened spatulate stigma.
The pistillody of the stamens is frequently [373] combined with another
deviation in the poppies. This is the growing together of some of the
altered stamens so as to constitute smaller or larger connate groups.
Often two are united, sometimes three, four or more. Flowers with
numerous altered stamens are seldom wholly free from this most
undesirable secondary anomaly. I call it undesirable with respect to
experiments on the variability of the character. For it may easily be
seen that while it is feasible to count the stamens even when converted
into pistils, it is not possible when groups of them are more or less
intimately united into single bodies. This combination makes all
enumeration difficult and inaccurate and often wholly unreliable. In
such cases the observation is limited to a computation of the degree of
the change, rather than to a strict numerical inquiry. Happily the
responses to the experimental influences are so marked and distinct that
even this method of describing them has proved to be wholly sufficient.
In extreme instances I have seen all the changed stamens of a flower of
the opium-poppy united into a single body, so as to form a close sheath
all around the central ovary. Lesser sheaths, surrounding one-half or
one-third of the capsule are of course less rarely met with. Leaving
this description of the outer appearance [374] of our anomaly, we may
now consider it from the double point of view of inheritance and
variability.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account