i- 



A Preliminary Survey of Species Crosses in the 



Genus Nicotiana from the Mendelian 



Standpoint. 



LIBRARY 

 BY NEW YORK 



BOTANICAL 



R. H. LOCK, M.A., Qarden. 



Fellow of Oonville and Gains College, Cambridge. 



CONTENTS. 



1. — Introduction. 



2. — The species employed in crossing. 



3. — The hybrid offspring obtained in F L 



4. — Impossible combinations. 



5. — The effect of conditions upon the form of the hybrids. 



6.— Sterile hybrids. 



7. — Partly fertile hybrids. 



8. — Fertile hybrids. 



I. — Colour of pollen. 

 II. — Colour of the corolla. 

 III. — -Shape of the corolla. 

 IV. — General features of the N. langsdorfii crosses. 



A. — Crosses with other species. 



B. — Crosses between supposed varieties of N. langs- 

 dorfii. 



V. — Other crosses. 



9. — Concluding remarks. 

 10. — Bibliography. 

 11. — Description of plates. 



I,— INTRODUCTION. 



^T^HE original crosses from which the plants described in 



-*- the present paper originated were carried out at Cam- 



^ bridge in the summer of 1906. The first generation of hybrids 



*— ^ (F 1 plants) was also grown at Cambridge in 1907. The seeds 



• of such of these plants as produced any accompanied the 



[AnnalB of the Royal Botanic Gardens, Peradeniya.Vol. IV., Part V., March, 1909.] 



^ 7(1)09 (26) 



