Spanish lawyer Bello y Espinosa was a self-taught naturalist with a particular interest in botany. He was born in La Laguna, on the island of Tenerife in the Canary Islands, where he studied Rights at the University of San Fernando and gained a doctorate. He briefly held the role of mayor in the city hall of La Laguna at the end of 1842 and between 1845 and 1847 was the secretary of the College of Lawyers in Santa Cruz de Tenerife.

In 1850 Bello y Espinosa emigrated to Puerto Rico where he had a successful law practice, married and had two children, and it was here that he taught himself and practised botany. He became close friends with Leopold Krug, an amateur naturalist and German consul stationed in Mayagüez, and together they made collections on the local flora, attempting to identify them and taking extensive notes. Their paths diverged when Krug, frustrated by the difficulty of maintaining collections in the tropics, began to draw the plants that he was studying.

In 1880 Bello y Espinosa returned to La Laguna and a year later published the first flora of Puerto Rico in Anales de la Sociedad Española de Historia Natural, Madrid, which was entitled "Apuntes Para la Flora de Puerto Rico", adding to this a second volume in 1883. It was an annotated checklist of 964 species based on his collections, many of which were new to science. This work, however, did not acknowledge Krug at any point, despite his influential contribution, and it strayed from their original plans. Krug was dismayed as he had expected this material to be a joint publication. Bello y Espinosa also contributed to the Revista de Canarias and the Ilustración de Canarias and published other botanical works as well. He also created a work of prose: Un Jardín Canario, and is respected for his literary skills. Unfortunately all of the original plant collections made by Bello y Espinosa in Puerto Rico were later destroyed by insects.