Page 71 - Knighted_2018

extensions of the plant body colonize approximately 10% of the foredune, 3.5% of the interdune,
42% of the dune, 46% in both dune and shellhash, and 74% of the backdune based on the
appearance of leaves visible above the sand (Wyatt unpublished). With below substrate shoots
and roots accounting for up to 93% of the dried biomass in the foredune, up to 86% in the dune,
up to 84% in the swale, and up to 90% in the backdune, it is possible that percent cover through
leaf visualization may inaccurately convey the importance of H. bonariensis in the dune system
(Wyatt unpublished).

Another adaptive feature of H. bonariensis may be its ability to alter nodal distances in
the different dune habitats. Plants in higher areas, such as the peaks of the foredune, dune, and
backdune display fewer nodes with larger internodal lengths (Knight 2004). Since leaf biomass
does not differ based on the internodal lengths, H. bonariensis may be more prevalent than meets
the eye (Knight 2004). Interactions with other floral species within the dune habitats may cause
localized adaption in such characters as internodal distance and number of nodes (Knight 2004).
Could including H. bonariensis in biotic dune retention models serve a mutually symbiotic
relationship with Uniola paniculata, allowing both species to thrive?

While Hydrocotyle bonariensis does produce seeds, most colonization is thought to be
asexual through the lateral branching of the rhizomatous shoots (Evans 1992). These shoots are
responsible for the transfer of water, nutrients and photosynthates (Evans 1988, 1992, 1992b). It
is suggested that H. bonariensis maintains the parameters of low stress environment through the
selective foraging of ramets (Evans 1988). The benefits of extending clones out into the higher
stress environments seems to outweigh the cost to parental ramets (Evans 1988).

Hydrocotyle bonariensis has been found in interconnected clones covering over 100
square meters with over 1500 ramets contained on one plant (Evans 1988). This clonal growth

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