RUIM’IA. 
.'{If) 
marginiil. — S])ooies 17, IS anil If) are very closely allied, but may 
be easily distinguished by attending to the eharaeters derived from 
the fruit. The ])resent speeies a|)jn-oaehes the ])reeeding by its 
leaves. Its fr. are 2 lines long with a somewhat facial style and a 
prominent rounded keel when dry, but no lateral ridges. — In the 
Serpentine, Hyde Park, London. Dr. J. A. Power. P. VII. E. 
18. P. pectinatus (L.) ; /. linear-set aceoxis I-nerved with trans- 
verse veins, spikes interrupted, fr. (large) roundly obovate 
rounded on the back with two lateral ridges but no keel when dry. 
— E.B.32',Vl R. vii. t. If). — L. narrower and more gradually 
aeute than in the preceding. Fr. 2 lines long with a somewhat 
facial style, their back rounded and prominent with a ridge on 
eaeh side but no true keel when dry. Fries and Koch describe 
the fr. as keeled, which can scarcely be correctly said of our 
plant which agrees well with Reichenbach’s figiu’e. — Ponds, 
scarce. Jersey. Surrey. P. VI. E. 
If). P. filiformis (Nolte!); 1. linear-setaceous 1 -nerved with 
transverse veins, spikes greatly interrupted, fr. (smaller) obovate 
rugose rounded on the back without keel or ridges when dry. — 
P. marinus Fries, Koch, R. vii.t. 18. — L. like those of the pre- 
ceding but longer. Fr. smaller and rounded on the back with- 
out keel or ridges. Whorls very distant on the spikes. Peduncles 
very long. — Rai’e. Forfarshire and Berwickshii'e. P. VI. VII. 
E.? S. 
[A plant found at Bath and Sandv\ich closely resembles P. tri- 
ckodes (R. vii. t. 21.) but has adnate stip. and transverse veins in 
its leaves. Its th'y fr. is semi-obovate, compressed, with 3 (?) 
obscure keels on the back. Probably a new species but I am not 
sufficiently acquainted with it to describe it.] 
***** L. all opposite, submersed ; stipules none. 
20. P. densus (L.); 1. all opposite pellucid clasping elliptical- 
lanceolate or lanceolate, spikes shortly stalked ultimately reflexed. 
— E. B. 397 . R. vii. t. 28. — L. crowded, rather recurved. Spike 
4-flowered. — Ditches. P. VI. 
2. Ruppia Linn. 
1. R. maritima (L.) ; cells of the anthers oblong. — R.vii. t. 26. 
— Wiole plant stronger than the next. L. very narrowly linear. 
Sheaths large inflated. Nut ovate, obliquely erect. — Salt marshes. 
Newhaven, Suss. Mr. Borrer. Guernsey. P. VII. VIII. O. 
2. R. rostellata (Koch); cells of the anthers nearly round. — 
R. R. 136? R. vii. t. 25. — Whole plant very slender. L. rather 
fihform than linear. Sheaths small, close. Nut obliquely as- 
cending, less so than in eontinental specimens. — Salt marshes. 
