About Carolus 'Clusius' de l'Escluse
French name Charles de l’Escluse
Origins of the name:
The name De L’Ecluse is associated with the Dutch- and French-speaking agricultural workers and settlers in the Fens of Eastern England 1626 – 1750 according to the literature references cited here. The Debrabandere (1993) dictionary of names also confirms its occurrence as a surname found in Belgium and Northern France. Here, the name is commonly listed under Delecluse.
Debrabandere advises De L’Ecluse is a place name; Ie, likely a name for someone living near a dam or sluice.
Variants of the name: de L’Ecluse, Delecluse
Birth date: 19 Feb 1526
Birth Place: Arras, France
Date of Death: 4 April 1609
Place of Death: Leiden, Netherlands
Buried in the Vrouwekerk in Leiden, next to his equally renowned colleague Josephus Justus Scaliger.
Father: Michel de l’Escluse, Seigneur de Watènes, was a nobleman who served as councillor at the provincial court of Artois.
Mother: Guillemette Quincault (daughter of Pierre Quincault and Jeanne Montmorency)
Marriage: Clusius never married
Occupation: Flemish Botanist; Author; Humanist;
He introduced exotic plants such as the tulip and potato in the Low Countries; advisor of princes and aristocrats in various European countries, professor and director of the hortus botanicus in Leiden, and central figure in a vast European network of exchanges.
Most responsible for introducing the tulip to the Netherlands.
"In the 1583 edition [of Rariorum plantarum historia (1601)] Clusius relates that an Antwerp merchant sometime earlier had received a consignment of cloth that unexpectedly included tulip bulbs, which were mistaken for onions, some of which the clothier ate, discarding the rest in his garden. (Although the year 1562 has been suggested, Clusius himself gives no date.) The unfamiliar flower piqued the interest of Joris Rye from nearby Mechelen, who transplanted the few surviving bulbs to his own garden, where they bloomed in 1564. Rye wrote to Clusius about the discovery and, although he then was in Spain, he may have seen them when he returned the next year. If not, he certainly would have seen them when he moved to Mechelen in 1568 to stay with a wealthy friend, whose garden he designed. This all is conjecture, however, as Clusius does not mention tulips in his writings until 1570, when a correspondent thanked him for the gift of a small bulb—and asked for a larger one."
Eventually, this fascination with the flower would effloresce as tulipmania. 
Charles went to university at Louvain, where he studied law under Gabriel Mudaeus.
1546 - entered the famous Collegium Trilingue.
1548 - briefly at Marburg as a law student, but his protestant conviction appears to have led him to Wittenburg, where he studied with the reformer Philip Melanchthon. On the advice of Melanchthon he changed his subject to medicine and botany.
Early in 1550 he spent some time in Switzerland.
In 1551 he was at Montpellier, studying with the botanical professor Guillaume Rondelet. The environment of Montpellier with its wealth of plants was particularly suited to develop and intensify his botanical tendencies. During these formative years he acquired no less than eight languages and an extensive knowledge on a wide variety of subjects.
When he finished his studies, Clusius worked in various places and occupations - including tutor and travel companion to the sons of Anton Fugger, Count of Kirchperg and Weissenhorn.
In the 1560s he was back in the Southern Netherlands, enjoying the protection of such influential patrons as Guido and Marcus Laurinus in Bruges.
In 1561 his translation of an Italian pharmacognosy completed this period.
During this period his also was involved in the production of the series of ‘libri picturati’, a collection of hundreds of watercolours of plants and animals (now in the Bibliotheca Jagiellonski, Krakow). After short stays in Paris and London, he was invited to Vienna by Emperor Maximilian II in 1573 as court physician and overseer of the imperial garden. This high patronage enabled him to travel all over Europe, collecting information for his botanical studies and introducing a range of new plants from outside Europe, including the tulip and the potato.
In 1576 his Spanish flora (Rariorum aliquot stirpium per Hispanias observatarum historia (catalogue nr. 8)) was published by Christopher Plantin at Antwerp, followed in 1583 by his description of the plants of Austria and neighbouring regions (Rariorum aliquot stirpium, per Pannoniam, Austriam, & vicinas quasdam provincias observatarum historia (catalogue nr. 9)). By then, religious conflict had forced his departure to Frankfurt, where he worked for the publishing firm of De Bry.
In 1593 Clusius was finally appointed honorary professor of botany at the University of Leiden, a chair which he occupied until his death.
The Officina Plantiniana published his collected works in two volumes between 1601 and 1605.
He founded the Leiden botanical gardens, the second such institution north of the Alps.
He received tulip seeds and bulbs from Ogier Ghiselin de Busbecq for the Vienna Garden. Clusius experimented with growing them and became an expert, writing his findings in 1601.
He took a collection of the best tulips in western Europe, and spread them by sending them to acquaintances.. The result was that tulip nurseries were established in Holland and a very successful industry boomed. The market finally collapsed in 1637.  
As court physician and director of the imperial garden, Clusius traveled all over Europe in search of new specimens.
His first publication was a French translation of Rembert Dodoens’ Cruydt-Boeck, published in Antwerp in 1557. 
 Clusius was a prolific letter writer and these were made available online in 2004 by the Scalinger Institute and Leiden University Library. http://www.library.leiden.edu/special-collections/scaliger-institute/projects/clusius-project.html
Email correspondence from Kasper van Ommen of the Scaliger Institute
"Indeed, Michel de l'Escluse, Seigneur de Watènes, was a nobleman who served as councillor at the provincial court of Artois. The mother of Carolus was Guillemette Quincault (daughter of Pierre Quincault and Jeanne Montmorency). Carolus had 3 brothers (Bernard, Louis and Jonathan) and 3 sisters (Marie and 2 unknown). Carolus was educated by his uncle (from mother's side)and prior Martin Quincault in the chapter school of the abbey of Saint-Vaast between 1540 en 1542.
The great father of Craolus was Pierre de l'Ecluse who was married to Jeanne du Boys. The parents of Pierre are not known, but the had a brother Bernard and a sister Marie.The children of Pierre and Jeanne were Michel (the father of Carolus), Mathieu and a 3rd unknown child." Kasper van Ommen
References, Sources/Links, Family Trees etc.
http://www.knaw.nl/Content/Internet_KNAW/publicaties/pdf/20061066_Clusius_02.pdf is an excellent study of Clusius
Dolezal, Helmut, "Clusius, Carolus", in: New German Biography 3 (1957), p. 296 f. [Online version]; URL: http://www.deutsche-biographie.de/pnd118890646.html