Schweinitz — who did his classic botanical/mycological work while employed as a preacher and church administrator — was a friend and professional colleague of Torrey, and met Nuttall (whom he described as “that excellent man”) in Philadelphia. Hooker and Martius were both correspondents, with whom he exchanged valuable specimens.
Martius spent three years travelling extensively in Brazil, collecting botanical and other specimens; Spix was his zoologist companion for much of these explorations. Schweinitz was among those to whom Martius sent specimens he’d collected. Agassiz, Schimpel and Braun all studied with Martius in Munich; Cuvier suggested Agassiz catalogue Martius’ collection of Brazilian fish (which he proceeded to do in Latin).
Braun befriended Schimper, Engelmann and Agassiz (a particularly close friend) while studying in Heidelberg, staying in touch with them for the rest of his life. He encouraged Agassiz to follow him to Munich for further study (citing the reasonable cost of lodgings, the quality and abundance of beer, and the excellence of the professors). Braun and Agassiz lodged with one of them, Döllinger, while he enthusiastically encouraged them in their studies; and together with Schimper they spent congenial evenings with Oken and Martius, smoking and drinking beer while discussing scientific and other matters.
Parry trained as a doctor (doctors then needing to know about the medicinal properties of plants), but taught by Torrey (who had a similar background), then turned to botany. Torrey and Gray both became lifelong friends and professional colleagues; Engelmann too. He made friends with Hooker (who respected him greatly) on a visit back to England.
Smith (whom Hooker consulted about a rare moss) suggested he specialise in botany. Bauer taught Hooker. Banks sponsored a research journey to Iceland (Hooker’s findings were all burned in a shipboard fire), and tried to persuade him to go on to Java. Hooker, with his colleague Talbot, was pivotal in the long-term survival of Banks’ botanic gardens at Kew, which had fallen into disrepair following Banks’ death. He helped persuade Bentham not to abandon botany. Joseph Dalton Hooker was his son, who succeeded him both as eminent botanist and as director at Kew.
Jeremy Bentham was his uncle; George worked as his secretary, and inherited his estate. William Hooker helped persuade Bentham not to give up botany, offering him a job at Kew; his son Joseph Hooker was a close colleague, collaborating on Bentham’s magnum opus. De Candolle was a close friend and colleague. Bentham corresponded extensively with Darwin (as well as visiting him, and eventually being persuaded by his ideas); with Torrey; and with his warm friend and colleague Gray.
Also known as Louis Charles Adelaide de Chamisso. Eschscholtz was his fellow-naturalist (and close friend) around the Pacific — they each named species new to science after each other. Chamisso was at the Berlin dinner where Hoffmann was unmasked as the pseudonymous music critic Kreisler, and translated Schlegel into French, staying with him (and Madame de Staël) in Switzerland. Tieck was a correspondent, Heine appreciated his later poetry, and Andersen became a good friend, staying with him in Berlin — Chamisso helped popularise the Dane’s work in Germany. Although Robert Schumann famously set his words to music, it was after Chamisso’s death.
Torrey’s association with his student Asa Gray began in the 1830s and led to their publication of ‘Flora of North America.’ He corresponded extensively with other botanists and naturalists, including Henry, Silliman, Parry, von Schweinitz, Hooker, Bentham, Rafinesque and Downing. He met the environmentalist Muir in 1872, the year before his death.
Engelmann met Schimper, Agassiz and Braun while a student, continuing the association with Agassiz and Braun in Paris. He met Gray after he emigrated to the U.S. Torrey stayed with him, while Parry became entangled with another botanical collector in an argument over a rose, which Engelmann tried to defuse (Parry having a long and close friendship with him). Hooker was one of his many correspondents.
Gray was Torrey’s pupil, swapped plant specimens with him, and assisted him with publication of the ‘Flora of North America.’ Gray and Henry corresponded copiously, as he also did with Engelmann and with Darwin, whose ideas he championed in N. America. Agassiz was a colleague at Harvard, whose creationist views Gray tried to mediate; Muir was a companion on several expeditions. De Candolle (father and son) received Gray cordially on a visit to Geneva. Both Huxley and Owen were met on one of his visits to England: like Gray, important participants in the coming debate about evolution.