Physiological integration of Thalassia testudinum short shoots enables clones to function at a higher level of physiological organization than that of the short shoots themselves. Shaded short shoots connected to non-shaded short shoots had blade growth rates and proximate organic constituent levels equal to non-shaded controls. Shaded short shoots physically isolated from neighboring short shoots had blade growth rates and organic constituent levels different from both controls and shaded short shoots connected to non-shaded short shoots. Support of shaded short shoots appeared to be primarily from older short shoots connected to the shaded short shoots. The amelioration of localized light limitation results in an increased ability of clones to persist in heterogeneous environments. This increases the probability of the clone later encountering more favourable sites through a wider physical spread.