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51 



approaches obligate autogainy. Reprcducticxi by cloning or 

 other asexu2Ll means has not been observed. 



2 . Pallination . 



a. Mechanisias: As described above, H. aquatilis largely 

 appears to be an obligate self -pollinator. 



b. SJpecific pollination agents: None kncwn or subjected, 

 although small insects (i.e., dipterons) have been very 

 rarely observed on the chasmogamous flcwers (J. Pierce, 

 pers. ccmn. ; J.S. Shelly, pers. observation). 



c. Other suspected pollination agents: None kncwn, 

 although it is possible that pollen transfer via water 

 might occur. 



d. vulnerability of pollination mechemians: None 

 suspected. 



3. Seed difpersal. 



a. General mechanisms: Ihe seeds of IJ. aquatilis are 



relatively large (2-4 rm. long) . They do not possess 

 any wings, appendages, or other structures which appear 

 to provide them with 2my buoyzmcy. Though capable of 

 floating on the surface owing to water surface tension, 

 the seeds sink readily when pushed or released belo^ 

 the surface. It is liJcely that all of the seeds 

 produced by the subniergent cleistogamous flowers sink 

 to the bottom upon release. Although seeds released 

 fron emergent capsules could float for a short distarce 

 from the point of di^sersal, it is li3cely that these 

 seeds sink fairly soon after release as well. 



The majority of the populations of H. aquatilis occur 

 in ponds which are not connected by above-ground 

 drainages or by ^ring run-off. The exception to this 

 is the Swan River Oxbow (005) site, where the species 

 occurs in four adjacent wetlands on the flooc^lain of 

 the Swan River. During years of hi^ spring run-off, 

 this area is inundated, and it is liJcely that these 

 wetlands aure thus interconnected. Water from the Swan 

 River was observed flowing through the surrounding 

 forests in June, 1986. In this situation, it is 

 possible that some dispersal of seed by water movement 

 is occurring. 



In numerous cases broken stems, be2u:ing fruits 

 produced by both cleistogamous and chasmogamous 

 flcwers, were observed floating in the water. These 

 fragments could be dispersed to other cureas within the 

 same wetland habitat, although the species is 

 restricted to very quiet water. 



