3 
Тһе Naiadacez are for the most part strictly aquatic plants, 
arising from long, sometimes nodose, rhizomes. Two of the 
genera now included in the order, Zriglochin and Scheuchzeria, 
are inhabitants of bogs and marshes; while another, / га, usu- 
ally begins its life under water, but continues to grow in the mud 
after its native water has subsided. Triglochin and Lilea bear 
their inflorescence on scapes, the remainder on branching and 
leafy stems.. The aquatics are normally submerged plants, but 
some of the Potamogeton family bear two kinds of leaves, floating 
and submerged. The leaves are properly sheathing at the base, 
and this appears in all the genera, except in some species of Pota- 
mogeton. Even these, however, as in the group of which 2. pec- 
tinatus may be considered as the type, the so-called stipule is adnate 
to the base of the leaf and forms with it a sheath, produced at its 
extremity into a sort of ligule. In the other species this organ, 
though, for want of a better name, it is termed a stipule, is much 
more in the nature of a spathe that at first encloses the young 
buds, remaining afterwards at the base of the elongated nodes, 
petioles and peduncles as an appendage which soon decays. In 
Zostera and Phyllospadix the spathaceous character is still more 
developed as the flowers are borne on true spadices contained in 
a foliaceous sheath or spathe. Flowers perfect, moncecious or 
dicecious, either naked, tubular, or with a perianth of 4 to 6 dis- 
tinct herbaceous segments. Stamens 1 to 6, occasionally more, 
distinct and hypogynous in the perfect flowers, solitary or connate 
in the unisexual, with extrorse 1-2-celled anthers. Ovaries 1 
to 6, distinct or rarely connate, I-celled; containing in our 
North American species, with few exceptions, a single ovule. 
Fruit, various; capsular, follicular or drupaceous. The fruit in the 
Zostere@ is usually termed an utricle, but, while having a mem- 
branaceous pericarp, it is frequently, at least, if not always, dehis- 
cent. Seed straight or curved; the embryo corresponding, ortho- 
tropous, anatropous or campylotropous, without albumen. 
From this brief characterization it will be seen that the order is 
composed of several heterogeneous groups. With the exception 
of the Juncaginez and Lilaez the order is a natural one. These 
two groups have long hovered between Alismacez, Aroidex and 
Naiadacez, with all of which they are more or less closely allied, 
