(c) Lathy rue japonicus . Fifty-three quadrats with Lathyrus 

 japonicus were buried by between 8 and 65 centimeters of washover sand. A 

 total of 24 quadrats (44 percent) recovered from as much as 43 centimeters of 

 burial; 29 quadrats failed to recover from overwash burial. 



Comparisons of recovered quadrats to quadrats that failed to recover, 

 using the Kruskal-Wallis test, showed that burial recovery is related to 

 initial cover but not related to initial density or burial depth (Figs. 49, 

 50, and 51). Using the 24 recovered quadrats, it was found that plant 

 recovery is not linearly related to burial depth, initial cover, or initial 

 density. Correlations were not found among any of the variables using multi- 

 ple regression. In 1977 there was no relationship between density and cover 

 for Lathy rue japonicus; but in 1978 there was a highly significant relation- 

 ship between density and cover (r » 0.589, P < 0.01). 



Lathyrus japonicus can recover from as much as 43 centimeters of overwash 

 burial. Brightnore and White (1963) reported ttiat Lathyrus japonicus can grow 

 through as much as 40 centimeters of aeolian sand burial. Plant recovery 

 shows no differential response to burial depth. Plants buried by 43 centi- 

 meters recover to biomass levels comparable to plants buried by less sand. 

 The physiological limit of Lathyrus japonicus may not have been reached in the 

 data available for analysis. The growth form of Lathyrus japonicus and the 

 sampling technique used may explain the correlation between initial and final 

 density. Well-established Lathyrus japonicus plants are larger than other 

 dune plants. A single aboveground axis commonly measures more than 40 centi- 

 meters. Density figures were calculated for all plants in both dune and marsh 

 areas using the number of individual axes breaking the substrate surface within 

 the 50-square-centimeter quadrat. Density and cover data for 1977 were not 

 correlated for Lathyrus japonicus because many individuals may have been 

 present in a quadrat but anchored in an adjacent area. Lateral buds break 

 dormancy along the Lathyrus japonicus stem just as in other dune and salt-marsh 

 plants, but internode length is much longer than in the other plants that were 

 analyzed. The amount of rhizome or stem and the number of individual leaves 

 present in any given quadrat will determine the number of axillary buds (plus 

 the original apex) present. A plant may be anchored in a quadrat but have no 

 apical meristem or lateral bud present. 



Unlike 1977, the 1 V8 cover and density for Lathyrus japonicus were highly 

 correlated. Recovering plants broke the sand surface in early June, which was 

 later than other recovering plants in the area. Individual plant growth was 

 robust during the summer, but aboveground internode length was much shorter 

 than in plants not affected by overwash burial or deep aeolian deposits. 

 Plants were more densely oriented about the central axis in 1978. 



Lathyrus japonicus grows on well-established, accreting dunes although 

 Ammophiia breviligulata growth may be very dense. Lathyrus japonicus, as 

 all dune species, requires high light intensity but is able to compete with 

 Ammophiia breviligulata for light by internode elongation. Lathyrus japonicus 

 plants found in high dunes with Ammophiia breviligulata have extremely long 

 axes with long internodes. As with Artemisia stelleriana e no seedlings of 

 Lathyrus japonicus were found in established high dunes. Lathyrus japonicus 

 frequently seeds in drift lines and can regenerate from rhizome fragments. 

 Plants found on high dunes were probably originally established in very low 

 areas and grew through washover and aeolian sand deposits. New dunes can be 

 colonized by the massive lateral rhizome systems of Lathyrus japonicus plants. 



100 



