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Anatomy of Spartina Toivnsendii. 
Apart from its usefulness, the grass presents interesting ecological 
features, ~and the present Gstudy was undertaken in the hope that it would 
throw some light on its adaptation to a life of periodic submersion, as wel 
as form an introduction to a contemplated series of experiments on its 
physiology. The distribution and spread of the plant has been treated 
fully by Stapf, who is still carrying out his observations on its ecology. 
External Morphology. 
Rhizome. Spartan grass owes its power of rapid extension mainly to 
its characteristic rhizomes, which vary in length from a few inches to over 
a foot, rarely exceeding one-quarter inch in diameter. Their length is 
dependent for the most part on the type of soil and the available space. 
They travel horizontally through the mud at a depth of from o, \ to 4 inches, 
but frequently in the young stages they show positive geotropism and pene- 
trate downwards for a short distance. Near their point of origin they are 
firm, with short hollow internodes. The greater portion of their length, 
however, is soft and flexible, the whole structure being adapted for pene- 
trating a soft substratum. Short scale leaves are found in the bud stage, 
but the mature rhizome is invested merely by colourless sheaths devoid of 
blade and ligule. After proceeding for a short distance, rooting more 
or less freely at the nodes, the tip turns upwards and gives rise to aerial 
branches. New rhizomes are produced sympodially, and in the early 
stages there is nothing to distinguish them from the aerial shoots, except 
that the latter remain for a longer time within the sheath and are given an 
upward tendency. The creeping axes are shorter in a stony substratum, 
and hence it may also be that the question of the available space plays a part 
in determining the tendency and consequently the ultimate formation of 
culm and rhizome. 
Culm. The erect cylindrical aerial axis, covered almost entirely by 
numerous investing leaf-sheaths which enhance its rigidity, reaches a height 
of from % to 4 feet. The first shoot arising from the upturned rhizome tip 
is usually the dominant one. Secondary culms spring distichously from its 
basal portion. Of these the lower and outer generally grow more quickly, 
checking the development of the higher ones. Only at the margin of the 
clump or belt is it possible for plants to develop all or most of their aerial 
shoots. 
Leaf. The leaves are also distichous. The first three or four are 
practically scales. As soon, however, as the axis rises above the ground 
short green-tipped blades appear, increasing in size as the stem is ascended, 
until they reach a length of twelve to eighteen inches. The lowest blades 
are thrown off at an early stage, separating at the articulation. This helps 
to distinguish this species from N. alterniflora , in which the lower blades are 
retained longer and wither gradually. A short soft-celled ligule, tipped 
