Fruit Set, Seed Viability and Germination of the European Native Spartina maritima in Southwest Iberian Peninsula

Spartina maritima is the only native cordgrass in Europe and Africa and plays an important role in European salt marshes as a primary colonizer. Many aspects of its reproductive biology are unknown. Viable seed production has been described as potentially very low to non-existent. Our primary objective was to evaluate the seed viability of S. maritima . We hypothesized that S. maritima was capable of producing viable seeds since we observed many new patches of this cordgrass. We analyzed 400 inflorescences in fruiting state from 20 different tussocks in three estuaries in the Southwest Iberian Peninsula and carried out a germination experiment. Spartina maritima was able to set moderate numbers of highly viable caryopses. Mature caryopses with embryos were recorded in 12.5 ± 2.9% of total spikelets, with high variation ranging from 0 to 45% among tussocks. Caryopses showed a high level of viability (89.0 ± 4.9%) and final germination fraction (85.3 ± 2.9%). The percentage of spikelets with all their stamens exerted was 38.3 ± 4.5%, being positively correlated with the percentage of mature caryopses with embryo, indicating that tussocks in which inflorescences reached a more advanced state of flowering when fruit set started would ultimately produce more fruits.