746 NAIADACEZ:. [Triglochin. 
connate and sheathing. Flowers small and inconspicuous, usually 
green, hermaphrodite or unisexual, variously arranged. Perianth 
either wanting, or of 3-6 inferior segments valvate in bud. 
Stamens 1-6, hypogynous; anthers basifixed, erect, 1—2-celled. 
Ovary superior, of 1-6 distinct or more or less connate carpels, 
each 1-celled with usually a single erect or pendulous ovule; 
style long or short, stigma various. Fruit of 1-6 indehiscent 
nutlets or utricles, rarely drupaceous. Seed solitary, testa mem- 
branous; albumen wanting; embryo straight or curved, radicle 
unusually large. 
A small order, dispersed over the whole world in marshy places, ponds, 
lakes, rivers, &c., also including some widely spread marine plants. Genera 16, 
species estimated at 120. The order cannot be said to have any important 
properties or uses. With the exception of Lepilena, which is found elsewhere 
in Australia alone, all the New Zealand genera have a wide range in both 
temperate and tropical climates. 
A. Flowers hermaphrodite. Perianth of 4-6 herbaceous segments. 
Marsh plants with linear radical leaves. Flowers on erect 
scapes. Perianth-segments 6 2 .. 1. TRIGLOCHIN. 
Aquatic plants with submerged or floating stems and leaves. 
Flowers in axillary or terminal spikes. Perianth- 
"segments 4 a8 * : .. 2. PoraMoGETON. 
B. Flowers wnisexual (except in Ruppia). Perianth wanting or minute and 
hyaline. 
* Stems and leaves filiform, submerged. 
Flowers hermaphrodite, 2 or 3 on a peduncle greatly 
elongating in fruit. Perianth wanting. Stamens 2; 
anthers almost sessile $ is .. 3. RUPPIA. 
Flowers unisexual, axillary, “nearly sessile. Perianth 
wanting or female small and hyaline. Stamen 1, fila- 
ment slender Ae rs SE Be .. 4, ZANNICHELLIA. 
Flowers unisexual, axillary, nearly sessile. Perianth 
of 3 hyaline scales. Stamens3; anthers sessile, cohering 
by their backs into a columnar mass .. ic .. 5. LEPILENA. 
** Stems creeping in sand or mud in salt water. Leaves ribbon-like, flai, 
nerved. 
Flowers unisexual, enclosed in the membranous sheathing 
base of a floral leaf 5: ae ar .. 6. Zostera. 
1. TRIGLOCHIN, Linn. 
Perennial marsh herbs. Roots fibrous. Leaves all radical, fili- 
form or rush-like, flat or terete. Scapes slender, naked, erect, 
bearing a raceme or spike of small green hermaphrodite flowers. 
Perianth-segments 3 or 6, herbaceous, concave, deciduous. 
Stamens 6, inserted on the base of the perianth-segments; fila- 
ments very short ; anthers didymous, extrorse. Carpels 6, distinct 
or more or less connate; stigmas penicillate ; ovules solitary in 
