252 University of California PuUications in Botany [Vol. 5 



The average height of the 95 plants grown in our cultures this past 

 year was approximately 2 m., the variation in height having extremes 

 at approximately 1.5 and 3 m. The average number of leaves was 

 33 and the range of variation from 31 to 37, while the number of 

 laterals to the last significant leaf was 17 with a range from 11 to 37. 

 The stand was remarkably uniform and compared favorably in this 

 regard with other cultures of N. Tahacum varieties which have been 

 grown in the pure line for ten years. The flowers are borne in 

 great abundance, at first from the terminal panicle and later from 

 the many flowering laterals. In our cultures, the" flowers were not 

 "pure white" but a greenish white for the tube and a dull white 

 with a suggestion of greenish for the limb. The color is ''white" 

 when compared with another white-flowered A". Tahacum variety 

 grown in our cultures for some years — i.e.. "White Tobacco," U. C. 

 B. G. 30/06 (cf. Setchell, 1912. p. 7)— but cannot be called white 

 in the sense that X. sylvestris Speg. and Comes is a white-flowered 

 tobacco. The length of the corolla tube will average approximately 

 45 mm. and the diameter of the limb 25 mm. The corolla tube is 

 slender and the infundibulum slightly swollen. The limb is broadly 

 and shallowly lobed with the lobes unpointed. The leaves are large ; 

 the average length of the fourth leaf up being 49 cm. and its 

 greatest breadth 24 cm. Its shape is elliptical lanceolate, broadly and 

 decurrently auriculate at the base, with the auricles equal and broadly 

 acuminate at the tip. A photograph of one of the plants not used 

 in the experiments until late in the season is appended (plate 35). 

 As noted by Mrs. Thomas, there is a striking variation in the num- 

 ber of flower parts. I found a number of three-parted flowers and 

 at the opening of the flowering season almost equal numbers of 

 four and five-parted flowers. Toward the end of the flowering season 

 five-parted flowers predominate. Throughout this report the name 

 given by Mrs. Thomas in her original paper — i.e., "Nic. tahaccum 

 Cuba" — is employed. In the University of California Botanical 

 Garden the plant number is 200/14. 



Three points were borne prominently in mind in planning the 

 carrying out of experiments to test for the occurrence of partheno- 

 genesis^ in these plants. In the first place, it seemed essential that 



1 Lacking the necessary definite cj'tological evidence, the term partheno- 

 genesis is throughout employed in a more or less unrestricted sense and as 

 equivalent to the production of normallv matured, viable seed without pollina- 

 tion (cf. Winkler, 1908, and Coulter, 1914, p. 119.) 



