The structure, type, morphology and location of secretory structures in leaves of 43 spe-
cies, 1 subspecies and 1 variety of 9 sections in Hypericum L. were comparatively studied using tis-
sue clearing, paraffin sectioning and thin sectioning. The results have shown that the presence of se-
cretory structures is a common feature of leaves in this genus. According to their anatomical charac-
teristics, the secretory structures can be divided into nodules, secretory cavities (canals) and tiny
secretory tubes. In their distribution in leaves the nodules fall into two types: the leaf edge type and the scattered type. According to the location of cavities in the cross sections of leaves, the cavities
can be divided into 4 types: the median type which is situated between the palisade tissue and
spongy tissue, the palisade tissue type, the spongy tissue type and the across-mesophyll type. Based
on the location of cavities and nodules in leaves, the species in Hypericum can be divided into 3
groups: group Ⅰ , in which only cavities are present; group Ⅱ, in which only nodules are present;
group Ⅲ, in which both cavities and nodules are present. The type, location, distribution density
and morphology of secretory structures are of some taxonomic value at the level of species and of sec-
tion in Hypericum L. From these observations, the evolutionary trends concerning the morphology
and anatomy of secretory structures and the affinity among sections in the genus Hypericum ate dis-
cussed.
