Graciosa Island, located north of Lanzarote, was thoroughly surveyed botanically by Webb and Berthelot on June 5, 1829. Their account highlights the island’s unique flora, marked by the presence of species that are rare or absent elsewhere in the Canary Islands[1].
The authors compiled a list of 29 species, including 7 chenopodiaceae, 5 legumes, 3 plumbaginaceae, 2 polycarpaceae, 2 plantaginaceae, 1 liliaceae, 1 grass, 1 euphorbiaceae, 1 boraginaceae, 1 caryophyllaceae, 1 composite, 1 geraniaceae, 1 cistaceae, and 1 frankeniaceae[1]. This composition points to a flora adapted to arid and saline conditions, dominated by halophytes and low-growing or creeping species.
Among the most characteristic and abundant species, Webb and Berthelot mention Atriplex Halimus (a broad-leaved variety not found on other islands), Salicornia fruticosa, Atriplex glauca, Salsola vermiculata, and Suæda fruticosa[1]. These plants make up the bulk of the island’s vegetation, thriving in salty, dry soils. The presence of Statice pruinosa, previously reported from Egypt by Delile, is also noted, along with Statice puberula, Reseda crystallina, Ononis ocreata, and Ononis pendula—all considered rare and found only in specific locations on Lanzarote or Graciosa[1].
Euphorbia piscatoria is the only common species of its genus on Graciosa, where it is mixed with chenopodiaceae, unlike other islands where it is more widespread[1]. According to the authors, of the 26 main species, ten to twelve are almost exclusive to this locality, while the rest, though present on other islands, occur in different proportions. Most are herbaceous and creeping species, hidden among woody plants.
Webb and Berthelot emphasize that Graciosa’s vegetation looks different from the rest of the archipelago, as the most abundant species on other islands are entirely absent here[1]. The timing of their collection—early summer—also affects the findings, as many ephemeral species disappear with the heat. Another important factor is seasonal grazing: residents of Lanzarote bring their herds to Graciosa in winter, contributing to the disappearance of certain perennial species that might otherwise survive the drought and heat[1].
In summary, Graciosa’s flora, as documented in 1829, stands out for its restricted composition and the presence of rare or exclusive species, making it a botanical enclave of special interest within the Canary Islands[1].