(c) Growth. Shoredune panicum is only weakly rhizomatous. It is a bunchgrass 

 with mostly erect culms up to 7 feet high; some of the largest culms may become basally 

 decumbent. Sand burial does not stimulate tillering and production of rhizomes like in 

 bitter panicum; instead, this species remains a dense, tall bunchgrass (Fig. 5). Morphological 

 differences other than growth habit are slight, and are discussed by Palmer (1972). 



(d) Ecology. Shoredune panicum is common on south Padre, particularly in 

 moist, lowland sites leeward of the foredunes. On the national seashore it occurs north of 

 Mansfield Channel for a short distance, but is apparently absent from the remainder, 

 although it has been planted at Twin Batteries and Pan Am sites. Reproduction from seed is 

 common, and this is presently occurring leeward of planted areas on the national seashore. 

 The growth habit of this species is of little value as a dune-building grass, but it appears 

 satisfactory for sand stabilization. If planted culms are closely spaced in a row, it offers 

 considerable protection as a windbreak. 



(3) Sea Oats (Uniola paniculata). 



(a) Geographic Range. Sea Oats range from Cape Henry, Virginia (Wagner, 

 1964), south along the Atlantic and gulf coasts into Mexico, and as far south as Tabasco 

 (Sauer, 1967); it is also found in Cuba and the Bahamas (Wagner, 1964). 



(b) Morphology. Sea Oats is a strongly rhizomatous perennial grass, with the 

 culms attached in bunches at the rhizome nodes. Internodes are short and congested at the 

 culm base (Fig. 19), except for one or two internodes which may elongate with age as 

 shown in Figures 22 and 23. Sheaths are strongly overlapping and clasping, and are much 

 longer than the congested internodes. Blades are long, and in some culms are over 1 yard. 

 The nodes are nearly always buried, and only the top of the sheaths and the blades protrude 

 aboveground. The inflorescence is a large, open panicle of numerous many-flowered laterally 

 compressed spikelets. 



(c) Growth. The growth of a newly planted culm is shown in Figures 22 and 23. 

 Buds at the nodes, which are congested at the culm base, elongate, and form tillers. Tillers 

 reach the surface at an angle to the primary culm, and form additional culms. New buds, 

 continually produced at the culm base, become oriented at nearly a 90° angle to the 

 primary culm. Tillers grow more horizontally, and become rhizomes, winch elongate, form a 

 node at the terminal end, and produce new buds and tillers. Later, a series of culm clumps 

 forms, interconnected by rhizomes. Vertical growth of the individual culms occurs bv 

 elongation and addition of leaves from the apical meristem. As sand is deposited on top of 

 the plants, both tillering and apical growth are stimulated; the oldest leaves, on the outside 

 of an individual culm, eventually become buried and die. When 3 or 4 vears old, the 

 vegetative culms may begin to elongate and flower (Wagner, 1964); after flowering, they die, 

 but are replaced by new tillers from the nodes. 



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