246 MISS MARIETTA PALLIS ON THE 
sicherlich auch eine bedeutende Rolle. . . . Bei einer grossen Ueber- 
schwemmung, wie die im Jahre 1897, bringen die Hochwasser grosse 
Mengen sehweren Geschiebes (Sand und Sehlamm) mit, setzen sie auf 
dem Plaur dort ab, wo er dem Ufer am niichsten ist, besehweren ihn und 
drücken ihn dadurch auf den Grund des Sees, der dadurch angefüllt und zum 
Sumpfe wird. An den im Delta gemachten Durstichen waren oft alte 
Plaurschichten zu sehen, die mit Sandschichten bedeckt waren, über welchen 
dann eine neue Schilfformation lagerte.” 
The gradual covering up of a Plav quite close to the grind where it 
is fixed must undoubtedly sometimes take place. Ап examination of the 
configuration of the ground near such a buried Plav would probably 
in most cases solve the above question. 
General Description of Phragmites communis, Trin., B. flavescens, 
Gren. y Godr.* 
The reed of the delta of the Danube t—viz., the reed which gives rise 
to Plav— differs from the reed of East Anglia (Phragmites communis, Trin.f), 
which gives rise to fen, (1) by its larger size, (2) by the colour of its 
glumes, and (3) by the fact that buds are more frequent on the nodes of 
the aerial portion of the shoot. Yet though these two varieties differ in the 
above particulars, the description which follows of the delta of the Danube 
variety of reed applies fairly closely to the East Anglian variety as well. 
When the plant is young (see p. 267) the aerial portion of its shoots is 
often 5°15 m.$ (about 17 feet) in length, and since the thickness of the 
Plav layer is often 1:5 m. (about 5 feet), the total length of the shoot is 
not infrequently as much аз 6'7 m. (about 22 feet), whereas the shoots 
of the East Anglian swamp-reed, measured from the surface of the fen, 
very rarely reach a length of 2:5 m. (about 8 feet 3 inches), and their 
rhizome portion is perhaps 1 m. (about 3 feet 3 inches); viz., their total 
length is about 3:7 m. (about 12 feet). The glumes of the Danubian 
* Phragmites communis, Trin., B. flavescens, Gren. & Godr. = Arundo istaca, Sieb. 
+ I found the same variety of reed near Tulcea in the Somova plexus of lakes—that is to 
say, in the Danube above the delta. It is probably the prevalent variety in the Danube—in 
Rumania at any rate. Grecescu gives Phragmites communis, Trin. as also occurring in 
Rumania, but I did not find it. 
Т have found a giant variety of the reed, probably P. communis, В. flavescens, Gren. & 
Godr., also growing commonly in Epirus (around the Gulf of Arta) and in Macedonia, but 
had no opportunity of examining it at close quarters. 
t 1 distinguish three varieties of reed in the Norfolk Broads. One of these is confined to 
the river Yare; another, the “ Black Feather," I have seen only on the Ant; and the third 
is generally distributed. I hope, later on, to publish the distinguishing features of these 
three varieties. 
§ The shoots were measured from the surface of the ground to the base of the “feather.” 
