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CONTRIBUTIONS TO
They occur in the epidermis of the pericarp in many Labiatæ,
as in Ziziphora, Ocymum ; in most Salviœ, for instance, lim-
bata, hispanica, Spielmanni, &c. ; and lastly, in Horminum
pyrenaicum. My uncle Horkel was familiar with them in all
these many years ago; Baxter noticed and published their
occurrence in Salvia verbenacea only. I can add to these
Dracocephalum moldavica.
R. Brown discovered them in the parenchyma of the peri¬
carp in the Casuarinœ, and I in the spongy inflated cellular
tissue in Picridium, vulgare, where they mostly occur in a
reticular form, and present an extremely beautiful appear¬
ance.
Horkel also discovered them in the epidermis of the seed
itself in the Polemoniaceæ long before Lindley made known
their presence in Collomia linearis. They occur in Collomia,
Gilia, Ipomopsis, Polemonium, Cantua, Caldasia, and perhaps in
the entire family, with the exception of Phlox, with which
genus Leptosiphon, in which are the first indications of them,
is closely allied. Horkel had also studied them in the seeds
of Hydrocharis, where they occur in the highest degree of deve¬
lopment, long before Nees von Esenbeck published the fact.
Robert Brown mentions them in the Orchideæ, which statement
I find confirmed as to most of our native species of Orchis.
I have also discovered very beautiful spiral fibre-cells in the
epidermis of the seed of Momordica elaterium, and a very deli¬
cate reticular formation of fibres in Linaria vulgaris, Datura
stramonium, in Salviœ, and in several other Labiatæ ; probably
it is common to the whole family.
Lastly, they occur, according to HorkePs discovery, in the
parenchyma of the integuments of the seed in Cassyta and
Punica.
Whether these formations be studied in their individual
development in a single species, or in their progressive stages
in a series of allied plants, some highly interesting general re¬
sults will be obtained in either case. The universal and alto¬
gether absolute fact at which we first arrive is, that the fibres
are never formed free, but are developed in the interior of
cells ; and that the walls of these cells in the young state are
simple, and generally very delicate. Cordais statement re¬
specting spiral cells without an enveloping membrane (lieber