Martius and the Sand Islands of the Amazon River

The Flora Brasiliensis is a landmark in global botany. Although started in 1840, its Volume 1 was published last, in 1906, featuring 59 illustrations of Brazilian landscapes. In this story, we will embark on a 'botanical journey' through one of them, highlighting its plants.

The Amazon River is the longest river in the world, stretching 6,992 kilometers. Numerous islands are scattered throughout this immense “sea of fresh water,” which flows from the high Andes to the Atlantic Ocean, between the Brazilian states of Amapá and Pará. 

Many of these islands are formed by the accumulation of sands from the Guiana Shield. They are low and flat islands, without rocks or reefs, and can be completely flooded or modified during the flooding season.

This low-lying landscape gains a peculiar characteristic from the quantity of “embaubas” (Cecropia latiloba), whose gently curved trunks with white bark extend their lobed and enormous leaves at great height above the shrubs on the banks.

Two other species always found on these islands are “oeirana” (Alchornea castaneifolia) and “Humboldt’s willow” (Salix humboldtiana). These narrow-leaved shrubs or trees are well adapted to floods and can be entirely submerged for part of the year.

Along the banks, we also see many species of grasses, notably “canaranas” (e.g., Echinochloa polystachya, Louisiella elephantipes), “water paspalum” (Paspalum repens), and “Guinea grass” (Megathyrsus maximus).

Where the land is slightly higher and reinforced by the accumulation of clay and organic matter, the species that form the igapó forests emerge. One of these is “munguba” (Pachira aquatica), which has digitated leaves and can reach up to 18 meters in height.

Also notable is the “caneleira-do-mato” or “louro-bravo” (Nectandra canescens), depicted here next to a giant “munguba” in the bottom-left corner of the engraving.

But perhaps the most distinctive species of these landscapes is the “açaí” (Euterpe oleracea), with its slender stems displaying a crown of pinnate leaves at the top. It is a slender and elegant palm whose silhouette can easily be recognized from afar.

Another aspect that we must highlight about the vegetation of these islands is the large quantity of climbers, especially “javillo” (Fevillea cordifolia), “passion flowers” (Passiflora sp.), the “bignonias” (e.g., Bignonia aequinoctialis), and many others.

The rivers are ecological reflections of the lands they drain and, in recent history, of the activities of human populations living along their banks. The future of the flooded forests depends on finding ways to reconcile development with conservation.