On the structure of the mucilage-secreting cells 
of Blechnum occidentale, L., and Osmunda 
regalis, L. 
BY 
WALTER GARDINER, M.A. 
AND 
TOKUTARO ITO, F.L.S. 
With Plates III and IV. 
I. Introductory and Historical 1 . 
I N ascending the Vegetable Kingdom it is among the Ferns 
that we first meet with any great variety in the forms of 
the hairs which occur on the young, or the adult, stem and leaf. 
At this point, however, associated with a rapidly increasing 
complexity of the aerial members, we find trichomes of the 
most diverse structure and function which may even rank with 
those of the highest of the Dicotyledons, and among the most 
interesting are the hairs which are endowed with the power 
of secretion, and thus contribute in an especially marked 
manner to some physiological necessity of the plant upon 
which they are borne. 
Such hairs have been long known. From the point of view 
of their secretion they may conveniently be divided into two 
classes, namely those secreting mucilage and those secreting 
1 In the case of composite papers it is not uncommon to attach all the credit 
to the person whose name appears first upon the title-page. I wish distinctly 
to state that it must not be so in the present instance. The work was certainly 
suggested by myself and carried out under my direction, but we have each of us 
done our own share in the investigation and worked in common through all the 
results. To Mr. Ito indeed fell the task, not only of making observations, but 
also of drawing the whole of the figures, and their wonderful and appreciative 
realism will sufficiently prove his capabilities more than any remarks of mine can 
do. For writing the paper I am myself responsible. — WALTER GARDINER. 
[ Annals of Botany, Vol. I. No. I. August 1887.] 
