As a rule, the bracts are grown together with their
axillary flower-stalk. This cohesion is not complete, nor is it always
developed in the same degree. Sometimes it extends over a large part of
the two organs, leaving only their tips free, but on other occasions it
is limited to a small part of the base. But it is very interesting that
this same cohesion is to be seen in the shepherd's purse, in the
wormseed and in the cabbage, as well as in the case of the _Erucastrum_
and most of the other observed cases of atavistic bracts. This fact
suggests the idea of a common origin for these anomalies, and would lead
to the hypothesis that the original ancestors of the whole family,
before losing the bracts, exhibited this peculiar mode of cohesion.
Bracts and analogous organs afford similar cases of systematic atavism
in quite a number of other families. Aroids sometimes produce long
bracts from various places on their spadix, as may be seen in the
cultivated greenhouse species, _Anthurium scherzerianum_. [640] Poppies
have been recorded to bear bracts analogous to the little scales on the
flower-stalks of the pansies, on the middle of their flower stalks. A
similar case is shown by the yellow foxglove or _Digitalis parviflora_.
The foxgloves as a rule have naked flower-stalks, without the two little
opposite leafy organs seen in so many other instances.
Pages:
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613