EARLY INVESTIGATIONS OF NORTH AMERICAN FLORA 
65 
considerable. There were in Upsala hardly any herbaria with 
foreign plants except Burserus’ Hortus siccus. He knew this 
collection already in 1730, for he cites some numbers of it in 
his ms. »Hortus Uplandicus». 
It is probable that the plants from North America made 
their entrance into Swedish gardens relatively late. I11 O. Rud- 
beck’s catalogues of the botanical garden in Upsala I have found 
only one such species, the »arbor vitae», i. e. Thuja occidentalis 
L. (in the catalogue of 1666). Perhaps some of the figures of 
American plants in the »Campus Elysius» of the same author 
(1701—02) are drawn from garden specimens, but this is not 
stated in the text. The next information we get about this 
matter is given by Linnaeus in his ms. »Hortus Uplandicus», 
dated 1730 (published by Th. M. Fries in Upsala Univ:s Års¬ 
skrift 1899; other of these mss. in »C. von Linnés ungdoms¬ 
skrifter», Stockh. 1888). Here are enumerated such plants as 
were cultivated both in the botanical garden and in other larger 
Swedish gardens, principally in the province of Upland. Of N. 
American species we here find only the following: Aster Trades- 
canti L., Erigeron annuus (L.) Pers., Rims glabra L., Rh. toxi¬ 
codendron L., Rudbeckia laciniata L., Sang?iisorba canadensis 
L., Solidago canadensis L. (?), Spircea hypericifolia L., Trades- 
cantia virginica L. 
From 1735 to 1738 Linnaeus was abroad. These years 
were of the utmost importance for the development of his know¬ 
ledge of foreign plants. This he points out in the preface to 
Species plantarum (1753), where he mentions his studies in 
the gardens of Paris, Oxford, Chelsey, Hartecamp, Leiden, Ut¬ 
recht and Amsterdam. In these he was able to examine many 
N. American plants then new to him. In such studies some new 
English works on garden plants may have been very useful, 
such as Dillenius’ »Hortus Elthamensis» (1732, dealing with 
Sherard’s famous garden) and Miller’s »The gardener’s dictio¬ 
nary» (first ed. 1731). He also went through many important 
herbaria, which he enumerates in the same place. Among these 
those of Hermann, Clifford, Burmann, Gronovius, Van Royen, 
5 — 2031- Sv. Linné-Sällsk. Arsskr. III. 
