Abstracts, XIV OPTIMA Meeting, Palermo (Italy) , 9-15
Abstracts, XIV OPTIMA Meeting, Palermo (Italy) , 9-15
Abstracts, XIV OPTIMA Meeting, Palermo (Italy) , 9-15
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<strong>XIV</strong> <strong>OPTIMA</strong> <strong>Meeting</strong>, <strong>Palermo</strong> (<strong>Italy</strong>), 9-<strong>15</strong> September 2013<br />
Morphometric and reproductive variation in the strict endemic Helichrysum<br />
melitense (Asteraceae) in Gozo, Malta<br />
XIBERRAS J., LANFRANCO S.<br />
Department of Biology, University of Malta, Msida, Malta. E-mail: sandro.lanfranco@um.edu.mt<br />
The aim of this study was to characterise the distribution, leaf-morphological amplitude and reproductive<br />
effort of the strict island endemic Helichrysum melitense (Pignatti) Brullo, Lanfranco, Pavone<br />
& Ronsisvalle (Asteraceae) in Gozo, Malta.<br />
This species is restricted to the coastal fringe of Western Gozo and was rarely observed further<br />
inland. Five main sub-populations, those at Ponta tal-Wardija, Tal-Port, Fuq il-Qawra, Ta’ Slima and at<br />
Il-Ponta ta’ Hekka, were recorded and surveyed. A total of 983 plants were investigated. The largest<br />
sub-population was that at Tal-Port (364 individuals) whilst the smallest was the one at Il-Ponta ta’<br />
Hekka (30 individuals).<br />
The plant has very low fertility. Out of 4877 flowers that were dissected, 2836 had not set seed,<br />
and only a small proportion (7.23%) of the seeds that formed were found to be potentially viable.<br />
Despite the low seed production, the overall population size has not been observed to diminish over<br />
the past thirty years, suggesting that this low reproductive rate may nonetheless represent replacement<br />
level for the species.<br />
Variation in leaf morphometry (leaf length, leaf width and leaf area) was investigated across the five<br />
main sub-populations. The sub-population at Il-Ponta tal-Wardija and Ta’ Slima had long and narrow<br />
leaves, those at Fuq il-Qawra and Tal-Port had short and narrow leaves while the smallest sub-population<br />
at Il-Ponta ta’ Hekka had very long and broad leaves. Variations in leaf morphometry within and<br />
across sub-populations showed low, non-significant correlation with environmental factors and thus<br />
were attributed to intrapopulation variation.<br />
Comparison of leaf morphometry between H. melitense and Helichrysum rupestre, (within which the<br />
Gozo populations were originally placed by Pignatti) showed a statistically-significant difference on<br />
the basis of leaf width. This does not confirm whether H. melitense is a distinct species or not, as leaf<br />
morphometry is highly variable across the genus Helichrysum.<br />
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