Anatomy of Spartina Townsendii . 349 
plete rows of stellate cells. Each space is always bounded by the intact 
radial walls which form limiting membranes. 
The result is that the inner cortex has a small number of radial rows 
of large intact cells, separated by air-passages, in each of which occur 
several persistent radial membranes bearing slight vestiges here and there 
of the tangential walls of the defunct cells. These membranes never occur 
in the air-passages of the stem, rhizome, sheath, or glumes. Where the 
rootlets are connected with the absorptive root there is always a sheath of 
fairly compact, non-stellate cells left, about four cells thick, to surround the 
inrunning axis as it crosses the cortex. 
The Inflorescence. The inflorescence of 3-13 somewhat spike-like axes 
conforms to the grass type, with one flower to each spikelet. These begin 
to form very early ; although flowering does not usually begin until August 
and September, their component parts are well established by the end of 
May. Lodicules are absent and the glumes are compressed, both adapta- 
tions to the plant habit. 
The surface and the contents of the versatile anthers are slightly muci- 
laginous as well as the plumose stigmas. The flowers are protogynous and 
wind-pollinated. 
In connexion with the scarcity of hairs on the vegetative portions of 
the plant, already commented on, their abundance on the glumes is 
interesting. Of course the inflorescence is subjected to less submersion, but 
that alone seems an insufficient explanation. Some of the glume-hairs are 
very large, especially on the keels, and have groups of cells lying against 
their lower sides. As these latter have numerous pits on their outer walls 
and also on their inner, they can absorb water readily, and possibly alter 
the angle of the stiff hairs. In this way they might play a part in opening 
and closing the flowers. It is also probable that they hold air-bubbles in 
the spikelets when submerged. 
Summary. 
Distribution. Spartina Tozvnsendii probably occurred along South- 
ampton Water considerably earlier than 1870 — the date of the earliest 
recorded specimen in the Warner Herbarium. Its present natural dis- 
tribution is limited by Selsey Bill and St. Alban’s Head, the boundaries of 
the sunken valley of the old Frome or Solent River. At those points the 
chalk ridges reach the sea, and outside them lie fairly long stretches of 
shingle beach or cliff, broken by a few or no suitable estuaries or mud flats 
for a considerable distance. 
External Morphology. There are two sets of roots. The anchoring or 
fixing roots are long, unbranched, devoid of root-hairs, and penetrate straight 
down into the mud ; the absorptive roots branch freely, forming a dense, 
more or less horizontal web. Both types occasionally show marked negative 
