The Flora of Galapagos is very diverse and plants are the basis of all life within the Galapagos Islands. With about 560 native species of "higher" plants (plants that came to the islands by natural means), about a third of which are endemic to the islands, the plant life of Galapagos is as extraordinary as its wildlife. Many species are so different from others elsewhere that they are grouped into their own endemic genera.
These include Scalesia, the endemic "daisy tree", which has evolved into a large number of different species in a direct botanical parallel to Darwin's finches. These plants, combined with the 200 species of introduced plants and 500 species of mosses, lichens and liverworts, form a complex ecosystem that can be divided into specific vegetation zones:
The lowest life zone on the island is the coastal zone. This evergreen zone is based on the salt-tolerant capacity of certain species at the land/sea interface. The type of vegetation found varies greatly and can be divided into zones: the Humid Coastal Zone or Mangrove Zone and the Dry Coastal Zone. Salt-tolerant mangroves form forests in coves and shallow salt waters. In Galapagos, there are 4 varieties of Mangroves Black Mangrove, White Mangrove, Red Mangrove, and Button Mangrove. In the dry coastal zone, especially on the beaches, there are creepers, grasses, and shrubs. Many plants in this zone are adapted to sea dispersal and few are endemic due to the unstable nature of the environment and high immigration rates.
This is the most extensive vegetation zone extending from the beach to a height of approximately 197 feet (60 m). It is a semi-desert forest dominated by deciduous trees and shrubs and home to many Galapagos cacti, including nopal, lava cactus, and candelabra cactus, as well as vines. Plants have adaptations to withstand drought. There are a large number of endemic species. Lichens are abundant in this area because they are able to absorb moisture from the occasional Garúa fogs.
It has an intermediate character between the Scalesia and dry zones but is dominated by species different from either of the adjacent zones, although plants from both zones are also found here. The forest is still mostly deciduous. It is much denser and more diverse than the forest in the arid zones and it is often difficult to tell which species is dominant.
The transition zone merges into the evergreen Scalesia zone, which is a lush cloud forest dominated by Scalesia pedunculata trees, hence the name of the zone. This type of forest is found only on the higher islands and, being the lowest of the wetlands, it is also the richest area in terms of soil fertility and productivity. It has been extensively logged for agricultural and livestock purposes. As is typical of a cloud forest, the Scalesia forest is very diverse and has many endemic species.
It is an intermediate place between the dense Scalesia forest and the shrubby Miconia vegetation. It is an open forest dominated by cat's claw, tournefortia pubescens, and aunistus ellipticus. The trees are covered with epiphytes, mosses, liverworts, and ferns, which give this area a brown appearance during the dry season. This zone has disappeared due to human colonization.
Above the Brown Zone, between 1950 and 2300 ft (600-700 m), is this humid zone named after the Miconia shrub that once dominated this region. The southern slopes of San Cristóbal and Santa Cruz are the only places where a dense shrub belt of the endemic Miconia Robinsoniana exists. Native trees are absent in this area and ferns are abundant in the herbaceous layer. There are also more liverworts than anywhere else.
The islands with elevations above 3000 feet (900 m) contain the highest vegetation zone in Galapagos, the Fern-Sedge Zone or Pampa Zone. There are virtually no trees or shrubs and the vegetation consists mainly of ferns, grasses and sedges. This is the wettest zone, especially during the Garúa season, receiving up to 2500 mm of rain in some years.
Endemic species of the Galapagos Islands
Below you will find descriptions of some of the many endemic plants of the Galapagos Islands:
Darwin's cotton (Gossypium darwinii, also called Galapagos cotton) is an endemic species of cotton plant found only in the Galapagos Islands. The Darwin's cotton is a shrub that grows up to 3 m tall and is easily identified by its large bright yellow flowers with a violet center up to 15 cm long. The oval seeds are up to 3 cm long and open producing white cotton that birds, especially finches and other small birds, commonly use to build nests. Galapagos cotton is best seen on the islands of Floreana, Isabela, San Cristobal and Santa Cruz. Genetic studies indicate that it is most closely related to native American species, so it is assumed that a seed arrived from South America on the wind, in bird droppings or with debris from the sea.
Within the Flora of Galapagos, the lava cactus (Brachycereus nesioticus) is a species of cactus and the only species of the genus Brachycereus. The cactus is a colonizer of lava fields, hence its common name and endemic to the Galapagos Islands. It has soft, hairy spines and grows in clumps to a height of up to two feet (60 cm). New growth is yellow and turns brown, which darkens to gray with age. The creamy white flowers are visible only in the early morning and often wither by 8 am. The fruits are dark brown to 3.5 cm long with yellow spines. The lava cactus is best seen on the Santiago Islands, Bartolome, Isabela, Fernandina, Genovesa and the Chinese Hat Islet.
The endemic cut-leaf daisy (Lecocarpus pinnatifidus) is named for the deeply lobed and irregularly lobed margins of its leaves. This small evergreen shrub grows mainly on bare lava or ash up to 2 m tall. It usually has a single stem and a bushy head of yellow daisy-like leaves and flowers. It is one of the rarest plants in Galapagos and in the world, known only from the Floreana Island. Other endemic species are found in the San Cristobal Island: Darwin's daisy, Lecocarpus darwinii and in Spanish: Fitzroy's daisy, Lecocarpus lecocarpoides.
The Galapagos croton (croton scouleri - chala) is an endemic shrub of the Archipelago that grows up to 6 m in height. There are four varieties of Galapagos croton. The Galapagos croton has gray bark, gray-green leaves and round fruits divided into three segments. The small cream-colored flowers sit on spikes up to 10 cm long. Croton sap has been known to stain clothing dark brown. It can be seen in Santa Fe, Santa Cruz, Genovesa, Santiago and San Cristobal Island.
Another species of plants and flora in Galapagos is the Nopal (Opuntia cactaceae). The Galapagos Nopal is the common name for the most numerous and widely distributed cacti on the islands. Opuntia are an excellent example of adaptive radiation with six different species divided into 14 different varieties ranging from the giant variation of Opuntia echios that grows up to 12 m (40 ft) tall to the barringtonensis variation of Opuntia echios found on Santa Cruz, whose truck measures 4 ft (1.25 m) in diameter. Its flat, jointed stems covered with small stiff hairs and spines identify the cactus.
The yellow flowers develop into a fruit covered with orange-red spines. These Galapagos cacti provide habitat and a food source for many of the islands' birds and animals, including two species of finches, pigeons, land iguanas, tortoises and mockingbirds. Opuntias can be found in the arid and transition zones of most of the Galapagos Islands.
Named for its shape, the candelabra cactus (Jasminocereus thingarsii) is a large endemic cactus that grows to heights of 23 feet (7 m). It has spiny, tube-shaped pads and green or red flowers 1 to 2 inches (2 to 6 cm) long that open before dawn and develop into globular, reddish-purple fruits ca. 10 cm long. The arms become more woody with age and when the plant dies, the hollow woody "skeleton" is left behind. All three variations of the candelabra cactus can be seen on several islands, but best on Santa Cruz, Sombrero Chino and Floreana.
Galapagos Lantana and Galapagos Purslane
Galápagos Lantana (Lantana peduncularis) is a small endemic shrub that grows up to 2 m tall. The white flowers with yellow centers form compact dome-shaped heads. Galapagos lantana can be seen on the islands of Santa Cruz, Santa Fe, Española and Floreana.
Galapagos Purslane (Calandrina galapagosa), an arid lowland shrub of the family Portulacaceae, is only found on San Cristóbal (Cerro Colorado) and is considered endangered. It was once frequently found at Sappho Cove on the northwest side of this island, but is believed to no longer exist there. Due to its endangered status there are several cultivation projects to germinate the seeds and return it to its natural habitat. The Galapagos Purslane is a perennial herb that is slightly woody at the base and fleshy at the stems and leaves. To see it visit the Interpretation Center on San Cristobal Island.
Galapagos Tomato and Miconia Plant
Galapagos tomato (Lycopersicon cheesmaniae), an endemic perennial herb, is found in arid lowlands, transition zones and Scalesia areas. Its numerous branches are covered with short hairs. The variety found on St. Kitts is L. cheesmaniae cheesmaniae and as on other islands, it is not cultivated. The tomato species grown on both San Cristóbal and Santa Cruz is L. esculentum, which is a common garden tomato. San Cristóbal growers are now working to cross these two species to create a more flavorful, endemic, organically grown variety to sell to the tourism sector.
The Galapagos Miconia plant (Miconia robinsoniana) is found in the southern highlands of the island, where there is sufficient wind and water. It is a large, highly branched shrub whose foliage ranges from green to dark red. It changes color from green to red depending on moisture and grows in dense, almost impenetrable stands over the scalesia zone, providing excellent nesting habitat for the dusky-rumped petrel. The long, thin, pointed leaves turn reddish in periods of drought. The flowers have about 4 petals, purplish in color and located at the tips of the branches. The miconia is best seen in the highlands of the Santa Cruz Island and on San Cristobal Island around the "El Junco" lagoon.
Galapagos Pega Pega and guayabillo
Pega Pega (Pisonia floribunda) is a large, branched tree that grows up to 15 m tall in the Transition Zone and is often covered with mosses and lichens. The flowers are in small inconspicuous clusters that produce a sticky fruit that aids dispersal by birds. The tree owes its Spanish name pega pega (sticky) to these sticky fruits. It is a much leafier tree than most in the area and is recognizable by both its shape and its rather dense foliage. The tree is best seen in the transition zone of Santa Cruz Island.
The guayabillo (Psidium galapageium), also known as Galapagos guava, is an easily identifiable endemic tree that grows up to 10 m tall with a smooth reddish-gray bark. There are two species of Psidium in Galapagos, but while the well-known cultivated guava (P. guajava) is introduced and highly invasive, the Galapagos guava is native to the archipelago and is found nowhere else in the world.
The Galapagos guava grows as a shrub or small tree and has simple, elliptical to ovoid leaves and relatively small white flowers. The fruit is a rounded berry that starts out yellow but turns reddish brown to black when ripe. There are two varieties of Galapagos guava, with the slightly larger P. g. galapageium being more common than P. g. howellii. It can be found in the arid lowlands and humid highlands, where it is a common component of the Scalesia zone and can be seen on the islands of San Cristobal, Santa Cruz, Pinta, Santiago, Fernandina and Isabela.
Tournefortia de Galápagos y arbusto de Darwin
The white-haired Tournefortia (Tournefortia pubescens) is a shrub from the Galapagos Islands that owes its name to the whitish hairs that cover its young branches and the underside of the leaves. The dark green leaves are elliptical or egg-shaped blades, while the fragrant inflorescences comprise alternate, tightly packed rows of small, tubular, five-lobed flowers. The flowers are white with greenish-yellow throats and the fruits are small, white and fine-fleshed. The shrub grows up to 3 m tall and can be seen in the highlands of Santa Cruz and Isabela.
Darwin's fine-leaved shrub (Darwiniothamnus tenuifolius) is a highly branched shrub that grows up to 3 m tall. It thrives in a variety of habitats, from lava fields to wet uplands. Leaves up to 10 cm long are alternate, usually clustered near branch tips, pointed and narrow and grow close together. The flowers grow in radiate heads, solitary or in clusters, borne near the branch tips and are daisy-shaped with white petals and yellow stamens. The fruit is ca. 1 mm long with numerous hair-like bristles on top, ca. 2 mm long. Its leaves have a pleasant odor when crushed and its flowers have a mild, sweet smell.
The endemic Galapagos passionflower (Passiflora foetida var. galapagensis) is a vine that climbs up to 5 m high and covers rocks and bushes. The leaves are up to 10 cm long and ivy-like. It has long tendrils that wrap around branches or stems of other plants and beautiful white flowers with a violet center. The fruits are up to 3 cm long, egg-shaped, and change color from green to orange as they ripen. It can be observed in the Scalesia and Miconia areas of Santa Cruz and Floreana as well as in Isabela.
The endemic tree of Santiago Scalesia (Scalesia atractyloides) is only found in the Santiago Island. The species was thought to be extinct until five plants were discovered in a crater in 1995 where wild goats could not reach them. The crater was surrounded by a fence in late 1997 to keep the goats out and protect the plants. In November 1998, two more adult plants were discovered at another site in Santiago, also on a cliff out of reach of the goats, and the hill where they were growing was immediately fenced off and it is hoped that the remaining plants can reproduce within these protected sites.
Galapagos Flax Floreana
Floreana flax (Linum cratericola) is a species that was not discovered until 1968 and was feared to be extinct some time after 1981, when it was last seen. Then, in April 1997, two scientists from the Charles Darwin Research Station (CDRS) discovered a small population of flax in a volcanic crater on Floreana Island.
There were only thirteen plants, only eight fully grown, in a small 2 x 1 m area. In July 1997, botanists visited again and discovered that the smaller plants had died leaving only eight, but five new ones were discovered on the cliff above. At last count, only six plants remain alive, but in June 1999 a project was initiated to study these few remaining plants in an attempt to save the species.
This is all the research we were able to do about the flora in Galapagos, if you are interested in discovering about the fauna in Galapagos, we invite you to click here. Here.
We hope that this article has been useful to you and we hope that it will be useful for your voyage through the Galapagos Islands.