PONDWEED FAMILY. 79 
Three or four species, occurring in salt and brackish waters all over the world. The following 
are the only ones known to occur in North America: 
Sheaths 3'’-4’’ long; drupes about 1’’ long. 1. R. maritima. 
Sheaths '%'-1's' long; drupes 114’ 
’ 
-2'' long. 2. R. occidentalis, 
1. Ruppia maritima IL. Mari- 
time Ruppia. (Fig. 176.) 
Ruppia maritima I,. Sp. Pl. 127. 1753. 
Stems often whitish, 2°-3° long, the 
internodes irregular, naked, 1/-3/ long. 
Leaves 1/-3’ long, 4%’ or less wide; 
sheaths 3//-4’’ long, with a short free 
tip; peduncles in fruit sometimes 1° 
long; pedicels 4-6 in a cluster, %4/-114’ 
long; drupes with a dark hard shell, 
ovoid, about 1’ long, often oblique or 
gibbous at the base, pointed with the 
long style, but varying much in shape; 
forms with very short peduncles and ped- 
icels, and with broad, strongly marked 
sheaths occur. 
Common in brackish or salt water along 
the Atlantic and Pacific Coasts of North 
America and in saline districts in the in- 
terior. Widely distributed in the Old World 
and in South America. July—Aug. 
2. Ruppia occidentalis S. Wats. 
Western Ruppia. (Fig. 177.) 
Ruppia occidentalis S$, Wats. Proc, Am. Acad, 
25: 138. Sept. 1890. 
Ruppia lacustris Macoun, Cat. Can. Pl. 5: 372. 
Novy. 1890. 
Stems stouter, 1°-2° long, the branching 
fan-like. Leaves 3/-S’ long, their large 
sheaths '4/-114’ long; branches and leaves 
often thickly clustered at the nodes, the 
sheaths overlapping each other; drupes 
larger, 114’/-2’’ long, ovoid or pyriform, 
borne on pedicels about 1’ long, the pe- 
duncles bright red when fresh and some- 
times nearly 2° in length. 
In saline ponds, Nebraska to British Co- 
lumbia. Summer. 
3. ZANNICHELLIA L. Sp. Pl. 969.1753. 
Stems, flowers and leaf-buds all at first enclosed in a hyaline envelope, corresponding to 
the stipule in Potamogeton. Staminate and pistillate flowers in the same axil; the stami- 
nate solitary, consisting of a single 2-celled anther, borne on a short pediccl-like filament ; 
the pistillate 2-5. Ovary flask-shaped, tapering into a short style; stigma broad, hyaline, 
somewhat cup-shaped, its margins angled or dentate. Fruit a flattish falcate nutlet, ribbed 
or sometimes toothed on the back. Embryo bent and coiled at the cotyledonary end. [In 
honor of J. H. Zannichelli, 1662-1729, Italian physician and botanist. } 
Two or three species of very wide geozraphic distribution in fresh-water ponds and streams. 
