VoL. 30 No. 3 
BULLETIN 
TORREY BOTANICAL CLUB 
MARCH, 1903 
Studies in Pant Hybrids: The Spermatogenesis of Hybrid Cotton 
By WILLIAM AUSTIN CANNON 
( WitH PLATES 7 AND 8) 
INTRODUCTION 
Perhaps the first suggestion that we have as to the possibility of 
crossing two or more less distantly related plants was given by 
Camerarius * in his letter to Valentini on the sexuality of plants. 
This was in the year 1694. In this letter Camerarius speculates as 
to the effect of crossing the hemp (Canzadis) and the hop (Humu- 
‘us), wondering whether the posterity of the form used as the 
mother would by this cause be altered. He did not make the 
cross, and in fact it was not until 1760 that the first plant hybrid 
which was of use to science was made. In that year K6lreuter,¢ 
perhaps the greatest as he was the first of hybridizers, crossed 
Nicotiana paniculata g and N. rustica 9 and obtained fertile off- 
spring, and thus began successfully the experimentation which he 
carried on with so great results for several decades. 
The first plant hybrid thus empirically formed served a good 
purpose by providing incontestable evidence upon certain of the 
leading biological questions of the day. It fortunately was of the 
intermediate type, and thus the fact that both parents contributed 
€qually to the formation of the hybrid offspring demonstrated at 
Once the falsity of the evolution or preformation hypothesis, gave 
* Camerarius, Ueber das Geschlecht der Pflanzen, translated from the Latin ‘‘ De 
Sexu plantarum epistola.’’ (Ostwald’s Klassiker der exakten Wissenschaften, 105 : 49. 
1899. ) 
tT Kélreuter, Vorlaufize Nachricht von einigen das Geschlecht der Pflanzen. (Ost- 
wald’s Klassiker der exakten Wissenschaften, 41: 30. 1893.) 
[The preceding number of the BULLETIN, Vol. 30, No. 2, for Febuary, 1903 (30: 
75-132), was issued 28 F 1903.] 
133 
