SHINGLING OF SU^EDA	105
from the surface projects an ever-widening thicket of closely-packed, erect, woody shoots. As successive prostrations tend to be in the same direction, the plant as a whole grows obliquely upwards in staircase fashion.
   Following successive advances of the beach a new lee edge forms each time and becomes populated by seedlings from the drift line. Thus it generally happens that the Suasdas occur in successive zones above one another, the zones being more or less parallel to the edge of the beach. It is only a question
 1
 2
 3
 4
Fig. *5.—Diagram illustrating the Mode of Ascent of Suceda fruiicosa from the Place of Establishment on the Lee Fringe up to the Crest of a Travelling Beach
  Four profiles (1, a, 3,4) in the travel of the beach are shown, and four Suaeda plants (a, b, c, d) successively establishing at each stage are represented. The existing portions of the Suaedas are given in continuous lines, the parts which have disintegrated by broken lines. The direction of beach travel is from right to left.
of continued beach travel for the Suasdas to reach the crest and eventually the sea face.
   For clearness, the history of the passage of Suaeda up the bank is summarized in two diagrams. At 1, fig. 25, a seedling plant a has established from tidal drift on the dormant lee fringe. In 2 the beach has advanced a short distance landward, the shoot of the plant a being deflected forwards by the shingle and pushing up buds into the air (one only represented). Meanwhile another plant b has established on the fringe. In 3 there has been further advance; the plants a and b behave as before, and a fresh plant c has arisen in the new fringe. Finally in 4 there has been a further considerable advance of the bank, with shingling over of a, b, and c, followed by the usual rejuvenescence. A seedling d has established on