EARLY INVESTIGATIONS OF NORTH AMERICAN FLORA 
67 
When Linnaeus stayed in Leiden he must have aquired a 
fair knowledge of the Virginian flora, for he visited Gronovius 
every day and helped him with his work on the Flora Virginica. 
He was also presented by him with specimens of most Virginian 
species. In Spec, plant, one of the most frequent quotations is 
»Gron. virg.» But in some cases he cites »Clayt.» or »Clayt. 
virg. » with a number attached, and this must denote numbers 
from Clayton’s collections not mentioned in Gronovius’ Flora. 
In 1741 Linnaeus published a little paper called »Decern 
plantarum genera» in the Acta reg. societ. scient. Upsaliensis. 
Six of the genera here described for the first time were from 
North America, viz. Ceanothus , Stewartia , (the name given by 
Lawson), Proserpinaca (the name given by Gronovius), Mimulus , 
Callicarpa , Poly premum. 
In the same Acta for the years 1743 and 1750 another trea¬ 
tise on N. American plants was sent in by Linnaeus to the 
same society. The title is »Plantae Coldengamiae in provincia 
Noveboracensi Americes sponte crescentes, quas ad methodum 
Cl. Linnaei sexualem, anno 1742. etc. observavit et descripsit 
C. Colden». The author had studied medicine in England and 
practised in Pennsylvania, later on he became lieutenant-governor 
in New York. He was very much interested in botany and 
after his arrival in America he had begun to collect the plants 
of the country, but had soon given it up, because he did not 
succeed in determining them with the aid of the literature then 
at his disposal. Later on he got Linnaeus’ botanical works 
and from that time he took up his botanical studies anew. A 
list of the plants he had collected, with descriptions of the 
new species, was sent by him to Gronovius, who in his turn 
sent them to Linnaeus, who obtained permission to publish them 
in Upsala. The knowledge of North American flora does not 
seem to have been much advanced by this paper, for of the 237 
plants contained in Colden’s paper only 80 are quoted in the 
2nd ed. of Gronovius’ Flora, and only 36 by Linnaeus, one 
of these (Uvularia sessilifolia) being new to science. The rest 
seem not to have been identified. 
