Zannic/tellia. J 
CV. NAIADACE^E. 
485 
base, or decurrent on the foot-stalks. The lower leaves appear to 
differ from the submerged leaves of all the others, except P. oblongus ,■ 
in having their substance composed of the same small, but distinct, 
cells or reticulations as the floating ones. These submerged leaves 
are frequently wholly wanting, especially when the plant grows in 
very shallow water. 
2. Ruppia Linn. Ruppia. Tassel-Pondweed. 
Flowers perfect, about 2 on a spike (or spadix ?) arising from 
the sheathing bases of the leaves, which perform the office of a 
spatha. Perianth 0. Stam.4. Anthers 1 -celled, sessile. Stigmas 
sessile, undivided. Achenes 4, on long stalks. — Named after 
Henry Bernard Ruppius, author, in 1718, of Flora Jenensis. 
1. R. maritima L. (Sea R. or T.) : E. B. 1. 136 : Hook, in FI. 
Lond. t. 50. — a. peduncles elongated, leaves broader, sheaths 
inflated. — 0. peduncles shorter, leaves narrow, sheaths small 
close. R. rostellata Koch. 
Salt-water pools and ditches. fl. 7,8. — Stems slender, filiform, 
flexuose, branched, leafy. Leaves linear, setaceous. Spadix at first 
very short, included in the sheath or spatha, with 2 green flowers one 
above another on opposite sides, and quite destitute of perianth. 
Anthers large, sessile, bursting horizontally, 1-cellcd. Mertens and 
Koch say that each pair forms the 2 cells of 1 anther ; and that there 
are in reality but 2 sessile stamens. Pollen a tube, with 3 globules, 
1 in the middle and 1 at each end of the tube. At the time of 
flowering the spadix lengthens remarkably, to the height of 5 or 6 
inches or more, and becomes spirally twisted. When the germens 
swell, their base is elongated into a footstalk, one or two inches long; 
each then becomes an oblique, ovate, acuminate, fleshy achene or drupe. 
This drupe is sometimes more beaked than at other times, and the 
sheaths of the leaves are occasionally but little dilated : then the plant 
becomes R. rostellata Koch, and this is the more common state of the 
plant with us. In R. maritima the anthers (anther-cells, Koch) are 
said to be oblong, times longer than broad, in R. rostellata nearly 
round or subquadrate. 
3. Zannichellia Linn. Horned Pond-weed. 
Flowers tnoncecious. — Barren fl. Perianth none. Siam 1. 
Filament elongated. Anthers 2 — 4-celled. — Fertile fl. Peri- 
anth single, of 1 scale. Germens 4 or more. Style evident, 
undivided. Stigma peltate. Achenes sessile or shortly stalked. 
— Named in honour of John Jerome Zannichelli, a Venetian 
apothecary and botanist. 
1. Z. paluslris L. (common H.) : E. B. t. 1844. 
Hitches and stagnant waters. 0. 5 — 8. — Floating. Stems long, 
filiform branched. Leaves opposite, linear, entire, sometimes emar- 
ginute at the point. Flowers axillary, from a membranous bractea. 
