4 to 41.5 centimeters. Rhizome length averaged 20.5 centimeters with a wide 

 range from 0.5 to 137 centimeters. There were no statistically significant 

 differences between oceanic and storm drift lines with respect to propagule 

 type. Bay drift lines, however, had propagules that were smaller than either 

 oceanic or storm drift lines. Eay drift material apparently is more frag- 

 mented before deposition than material deposited elsewhere. 



For each fragment the point of initiation of new growth was located and 

 recorded as the burial depth. Mean depth was 11.6 centimeters for all sites, 

 with a range from 3 centimeters in the bay and storm drift lines to as much as 

 34 centimeters in oceanic drift line.?. Excavations in other areas indicated 

 that fragments buried by 1 meter of sand can remain alive and begin to grow. 

 Fragments buried at 90 centimeters in April 1979 recovered and grew to the 

 sand surface within 5 weeks. 



Mean fragment depth was 8.4 centtiteters in bay drift lines, 9.8 centi- 

 meters in storm drift lines, and 16.5 centimeters in oceanic drift lines. 

 Bay and storm drift-line burial depth means did not differ significantly 

 (P > 0.05), but both did differ from oceanic drift lines (P < 0.01). Recovery 

 of fragments from lower burial depths in oceanic drift lines reflects the 

 overall morphology of these features and not differential survival of propa- 

 gules at varying depths. Successive deposition of drift material on the ocean 

 beach caused fragments to be buried much deeper than in other areas. 



New tillers may originate from a continuation of a previously growing 

 shoot or from buds located along rhizomes. Seventeen percent of the Nauset 

 Spit-Eastham fragments had tillers that recommenced growth; 84 percent had 

 lateral buds that broke dormancy. 



The number of new tillers supported by a fragment is a measure of either 

 reallocatable reserves of that fragment or environmental conditions within 

 the habitat. Fragments were excavated in June, and the number of new till- 

 ers, including axes that had not yet broken the sand surface, was recorded 

 (Table 35). Statistical analysis showed th.at the number of axes present 

 on oceanic and storm drift -line fragasents Is not significantly different 

 (P > 0.05). Bay drift-line fragments, however, supported significantly 

 (P < 0.05) fewer tillers than either of the other types of fragments. Bay 

 drift-line fragments were significantly smaller than others, which may indi- 

 cate that reallocatable reso; :ces were less available. 



In August 1978 fragments at the same sites wure again excavated and tiller 

 numbers were counted. In the oceanic and storm drift lines, mean tiller 

 number declined (Table 35), probably because some tillers that originated near 

 the sand surface died during the late July to early August drought. The 

 number of bay drift-line tiller? per fragment 'net-eased. The mean tiller 

 number at all three site3 did not differ significantly in Augusr. Smaller 

 fragment size (and therefore lower reserves) founG in bay drift lines did not 

 seem to be important in the ultimate number of tillers produced, since once a 

 tiller reaches the sand surface, photosynthesis provides the major source of 

 carbohydrates needed for growth. 



142 



