88 



ZANNICHELLIACEAE. 



VOL. I. 



2. RUPPIA L. Sp. PI. 127. 1753. 



Slender, widely branched aquatics with capillary stems, slender alternate i-nerved leaves 

 tapering to an acuminate apex, and with membranous sheaths. Flowers on a capillary spadix- 

 like peduncle, naked, consisting of 2 sessile anthers, each with 2 large separate sacs attached 

 by their backs to the peduncle, having between them several pistillate flowers in 2 sets on 

 opposite sides of the rachis, the whole cluster at first enclosed in the sheathing base of the 

 leaf. Stigmas sessile, peltate. Fruit a small, obliquely pointed drupe, several in each cluster 

 and pedicelled ; embryo oval, the cotyledonary end inflexed, and both that and the hypocotyl 

 immersed. [Name in honor of Heinrich Bernhard Rupp, a German botanist.] 



In the development, the staminate flowers drop off, the peduncle elongates, bearing the pistillate 

 flowers in 2 clusters ; after fertilization it coils up and the fruit is drawn below the water. 



Three or four species, occurring in salt and brackish waters all over the world. Type species : 

 Ruppia maritima L. The following are the only ones known to occur in North America. 

 Sheaths 3" 4" long; drupes about i" long. i. R. maritima. 



Sheaths J^'-iJ^' long; drupes \y 2 "-z" long. 2. R. occidentalis. 



i. Ruppia maritima L. Sea- or Ditch-grass. Tassel Pondweed. Fig. 209. 



Ruppia maritima L. Sp. PI. 127. 1753. 

 Ruppia curvicarpa A. Nelson, Bull. Torrey 

 Club 26: 122. 1899. 



Stems often whitish, 2-3 long, the in- 

 ternodes irregular, naked, i'-3' long. Leaves 

 i '-3' long, -I" or less wide; sheaths 3" -4" 

 long, with a short free tip ; peduncles in 

 fruit sometimes i long; pedicels 4-6 in a 

 cluster, \'-\\' long; drupes with a dark hard 

 shell, ovoid, about i" long, often oblique or 

 gibbous at the base, pointed with the long 

 style, but varying much in shape ; forms 

 with very short peduncles and pedicels, and 

 with broad, strongly marked sheaths occur. 



Common along the coasts and in saline dis- 

 tricts in the interior. Old World and South 

 America. Tassel-grass. July-Aug. 



2. Ruppia occidentalis S. Wats. West- 

 ern Ruppia. Fig. 210. 



Ruppia occidentalis S. Wats. Proc. Am. Acad. 



25: 138. Sept. 1890. 

 Ruppia lacustris Macoun, Cat. Can. PI. 5 : 372. 



Nov. 1890. 



Stems stouter, i-2 long, the branching 

 fan-like. Leaves 3'-8' long, their large sheaths 

 i'-ii' long; branches and leaves often thickly 

 clustered at the nodes, the sheaths overlapping 

 each other; drupes larger, ii"-2" long, ovoid 

 or pyriform, borne on pedicels about i' long, 

 the peduncles bright red when fresh and some- 

 times nearly 2 in length. 



In saline ponds, Nebraska to British Columbia. 



3. ZANNICHELLIA L. Sp. PI. 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 staminate 

 solitary, consisting of a single 2-celled anther, borne on a short pedicel-like filament ; the 

 pistillate 2-5. Ovary flask-shaped, tapering into a short style; stigma broad, hyaline, some- 

 what 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 wide distribution in fresh water, the following typical. 



