Lag.

Mariano la Gasca y Segura (Mariano Lagasca)
Statue by Ponciano Ponzano in the Royal Botanical Garden of Madrid
Born	(1776-10-04)October 4, 1776 Zaragoza, Spanish Empire
Died	June 23, 1839(1839-06-23) (aged 62) Barcelona, Spanish Empire
Nationality	Spanish
Occupation	botanist, doctor, writer
Known for	improvement of the Real Jardín Botánico de Madrid (Royal Botanical Garden of Madrid)

Mariano la Gasca y Segura (1776–1839), also known as Mariano Lagasca, was a Spanish botanist, writer and doctor. He was the director of the Real Jardín Botánico de Madrid (Royal Botanical Garden of Madrid).

Mariano la Gasca y Segura was born in Zaragoza, in Spain on October 4, 1776, to a wealthy Catholic family. He studied at the local elementary school and, afterwards, he continued his ecclesiastical studies in Tarragona. During his studies in Tarragona, he developed an interest for medicine and botany. After finishing his studies in Tarragona, he started travelling until eventually studying medicine at first in Zaragoza, and later in Valencia and Madrid.

In 1800, he moved to Madrid where he met Antonio José Cavanilles, a well-known botanist and doctor and became his disciple. In Madrid, he cooperated in various fields José Demetrio Rodriguez, and co-published with him a botanical book titled Description of certain plants of the Royal Botanical Garden of Madrid (Spanish: 'Descripción de algunas plantas del Real Jardín Botánico de Madrid') in 1801.

In 1802, he co-published with Simón de Rojas Clemente y Rubioa volume of articles regarding medicine and botany. After the death of José Cavanilles in 1807, he was appointed to the position of the vice-director of the Royal Botanical Garden of Madrid. During that period, he was also working as a professor of Botany at the university of Madrid.

In 1815, after the Peninsular War, he was appointed to the position of the director of the Royal Botanical Garden of Madrid. In the following years, he would become well known in Spain, because of his work at that position. In 1823, he was exiled from Spain because of his liberal political views. He spent the following eleven years in London, until his return to Spain in 1834 where he regained his position as a director of the Royal Botanical Garden of Madrid. He died five years later, on June 23, 1839, in Barcelona.