Case study of Juncus
Griseb. - a member of the section Juncotypus
Anatomy and morphology of Juncus uruguensis Griseb. were studied in order to determine the sectional position of the species. Leaf anatomy (Fig. 1), a decisive criterion for sectional classification in the subg. Agathryon, shows that the species should be placed in the sect. Juncotypus, not in the sect. Steirochloa.
is characterized by the following features of leaf anatomy:
Leaf T.S. is not round (it is usually ± elliptic,
see also Fig. 1) but is
polysymmetric, with distinct grooves and ridges; there is no
distinguish adaxial side of leaf. Cellulae bullatae are absent,
are arranged in one subepidermal circle, and are connected to epidermis
strands of sclerenchyma. Separate sclerenchyma strands are lacking.
sheaths are parenchymatous. Pith is parenchymatous, later coalescent.
is formed by small cells and covers the entire blade surface. Epidermal
are slightly enlarged on the ridges.
When the leaf T.S. characters of J. uruguensis are compared with those given in the, J. uruguensis is to be classified as a member of the sect. Juncotypus. The other characters either point to the sect. Juncotypus or are intermediate between the two sections.