"2. What sort of a seed, and what kind of a fruit.
"3. How the plant appears otherwise; its root; its stem, if it has any; and its leaves.
"4. To make remarks on the occasional peculiarities of the plant; of my own on the smell, taste, etc., and of what others say, of which one story in a hundred may be true.
"If I could make an herbarium in whole or in part, it would be so much the better. I might plant the more important specimens in my garden. A good friend, who has the knowledge and the disposition to help me, would be of great advantage (Mr. Young, three miles from here).
"Materials to be taken on excursions: An inkstand, with pen and paper, and a box to carry my plants in safely. And when possible, a microscope. Besides the box a few sheets of paper stitched together in folio, in which to lay the plants and carry them; to be tied up in front."
It was not long before Muhlenberg became engaged in correspondence with other botanists. Dr. Johann David Schöpf, an officer of the Hessian troops stationed in New York during the Revolutionary War, who traveled through the Eastern States to Florida, after the conclusion of peace, in search of medicinal plants, became acquainted with Muhlenberg and was assisted by him. After his return to Germany he was the occasion of a correspondence between Muhlenberg and Prof. Schreber, of Erlangen, and this was followed by exchanges of letters with other eminent botanists in Germany, England, France, and Sweden, as well as with Americans.
Like a true naturalist, Muhlenberg continued to exercise the greatest care and thoroughness in observation and research. A botanical excursion and note book of 1785 contains the following plan of work:
"This year I shall again keep a calendar of all plants as I may observe them, especially when in bloom. When I am quite certain, I shall set down only the Linnæan name; when not quite certain, I shall make a full description. Especially shall I try to complete the descriptions of 1789 in those kinds of plants in which many species are most exact. As I very carefully explored this region last year, I shall this year visit other regions, namely: 1. The mountains on the Susquehanna, in May and July. 2. The mountains called Chestnut Mountains, also twice, etc. I must further call upon apothecaries and take other pains to learn the officinal plants, their virtues and their common names. I must this year pay particular attention to the seeds, and especially to describe all herbs as completely and exactly as possible, especially when I am not wholly certain. I shall give particular attention to those of which there are many species, such as asclepias, con-
