ON THE ORGANS OF SECRETION IN THE HYPERICACER 451 
On the Organs of Secretion in the Hypericacew. By J. R. 
Gnr&w, B.Sc., Scholar of Trinity College, Cambridge. 
(Communicated by Dr. S. H. Vixzs, F.L.S.) 
[Read December 20, 1883.] 
(Prates XXXIX. & XL.) 
Tue natural Order Hypericaceæ is conspicuous among flowering 
plants on account of the numbers of secreting glands, resin- 
passages, and reservoirs of ethereal oil which are formed in the 
tissues of its species. The genus Hypericum, from which the 
Order takes its name, is the most noteworthy in this respect. 
Casual inspection of many of the commoner species of this genus 
Shows that their leaves are studded with minute translucent 
dots, giving them a remarkable appearance when viewed by 
transmitted light. If almost any part of the plant be bruised, a 
peculiar fragrance may be observed, due to the escape of the 
ethereal oil or resin with which the tissues abound. In the ripe 
fruits of most species this resin may be observed oozing in con- 
siderable quantity from any wound. Besides the translucent 
dots there may be seen others of dark purple colour, almost 
black indeed, which are not so generally distributed, but 
yet are scattered about many parts of the plant. They are 
especially prominent on the floral leaves of H. hirsutum, where 
they are placed each on a kind of tooth or projection of the leaf, 
and form a row of knob-like bodies along its margin. In H. 
perforatum they are conspicuous in both floral and foliage leaves, 
generally being arranged at short distances from each other 
around the margin, but not so regularly as in the other species 
named, and not being in projections of the leaf. In some cases, 
especially on petals, these black bodies take the form of irregular 
patches, often of considerable extent. 
In some species, such as Z. calycinum, H. pyramidatum, H. 
hircinum, &c., which have thick, somewhat leathery leaves, with 
pellucid veins, there seem at first sight to be none of these trans- 
lucent dots. In consequence, the genus has been roughly 
divided into two sections, marked respectively by the presence 
or absence of them. The division is not, however, an accurate 
one, for their apparent absence from the species forming the one 
section is due to their being situated under certain layers of the 
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