34 BOTANICAL GAZETTE | [JULY 
Juncaginaceae 
Of the five genera of Juncaginaceae, none possesses leaves with 
pseudo-laminae. Certain species of Triglochin have ribbon-like 
leaves, for example, T. montevidense Spreng., figured by SEUBERT 
(18, pl. XII), and 7. procerum R.Br. It is hoped to deal with 
the leaf anatomy of this genus in a later paper. Except in the 
case of these few ribbon-leaved species, all the five genera have 
leaves with a sheathing base and a radial or ensiform limb, with 
a typically phyllodic anatomy. In Triglochin, Lilaea, and Scheuch- 
zeria, a ligule generally marks the boundary between sheath and 
limb (9). Fig. 7 shows the transverse section of the limb of the 
leaf of Scheuchzeria palustris L. Its curious asymmetry has been 
figured and commented on by RAUNKIAER (15). The leaf of 
the monotypic Maundia, judging from BucHENAUv’s figure of the 
transverse section (8, fig. 7, p. xvi), is phyllodic, and similar to 
that of Triglochin maritimum (1). I have cut the leaf of the 
monotypic Lilaea subulata Humb. et Bonpl., and, although the 
herbarium material available was not very favorable for anatomical 
work, it was obvious that here also the structure is phyllodic. 
The leaf, which is described as awl-shaped and cylindrical in the 
fresh condition, is supplied by a series of small peripheral bundles in 
addition to three main strands. Hirronymus (11), in a Spanish 
monograph of Lilaea published forty years ago, definitely states 
that the leaves of this plant consist only of sheath and petiole, 
the lamina being unrepresented. 
It was interesting to find, on examining the fifth genus (the 
monotypic Tetroncium magellanicum Willd.) that the leaf is unusual 
among the Helobieae in being of the ensiform type, and in having 
a bundle system identical with that of the isobilateral equitant 
leaves which are so familiar, for instance, in Iris. In fig. 4, A shows 
the structure of the sheath region, B the transition to the limb, 
and C the limb itself, which has a close anatomical resemblance to 
that of Tofieldia calyculata Wahl., one of the equitant members of 
the Liliaceae (1). F ibrous sheaths are associated with the bundles. 
Potamogetonaceae 
In this family there are three types of leaf, corresponding to 
those met with in the Alismaceae and Butomaceae. The rarest 
