274 MISS MARIETTA PALLIS ON THE 
(5) That the water be deep enough to prevent the reed filling it 
completely ; and 
(c) That if there be floods, the amount of silt borne by them be small. 
4. Change of level of the water or storms are probably almost always 
nécessary to effect final detachment. 
5. The reed forming the Plav is probably succeeded by “ sedge’ 
(Cladium), or “ mixed-sedge " (Carices), and finally by salt-marsh plants. 
The only competitor with the reed is Typha ( T. angustata, Bory & Chaub., 
in the delta, and 7. angustifolia, Linn., in the Norfolk Broads), but 
apparently it merely inhibits the growth of the reed for a short time. 
6. East-Anglian fen and Plav are fundamentally similar, viz., in structure 
and in origin. 
7. The reed-shoots of Plav vary strikingly in size (in the Norfolk Broads 
this is also the case, but the variation is less conspicuous). The change in 
size of the shoots is regarded, in this paper, as a progressive morphological 
> 
change, senescence which precedes the death of the reed. 
8. The reed-shoots are regarded as building up a more or less definite 
whole—the reed major unit or reed-soma; and the reed-shoots themselves 
as the minor units or individuals. 
9. The major unit is regarded as the total vegetative output which one 
fertilized cell is capable of initiating, and the minor unit as that portion of 
the major unit which is able to produce a replica of the specific soma of 
the major unit. 
10. Major and minor individuals are regarded as fundamental units in 
botany, the former as a constant, its mass as the measure of specific vital 
energy. The major individual, however, does not necessarily develop its 
mass in one piece, hence it cannot, in general, be weighed directly. 
11. Unlike the major, the minor individual is not a constant, for it varies 
in size. The variation in size, as already stated, is regarded as morpho- 
logical and as testifying to the finite duration of the major unit, whose 
absolute age is thus indicated. In the reed the giant shoots are regarded as 
the lowest or morphologically juvenile branches of a vast branch-system 
the first and final branches of which do not co-exist. 
12. * Vegetative reproduction” is regarded, in essence, as growth of the 
major unit or soma, and as taking place through the multiplication of the 
minor individuals. 
APPENDIX A. 
Grind от Gradi*: according to the fishermen а high spot of firm soil 
situated in the Balta. Grinds are, in fact, Balta islands of various shapes, 
sizes, heights, and soils. Most of them, for instance the grindul Malului 
* Dr. Antipa devotes a section of his book, pages 100-113, to grinds. The account which 
follows ia to a great extent an abridgment of his description. 
