1912] Goodspeed: Nicotiana Hybrids 133 



On August 20. the three varieties were fully developed and 

 covered with flowers. In general habit variety II and variety 

 III were almost identical. Some trace of fasciation was ob- 

 served in two plants of variety III and its habit throughout was 

 a trifle the least robust. The leaf characters were the same in 

 these two numbers, though variety III has always exhibited a 

 somewhat ragged appearance in this connection which is not 

 shared by variety II. but is also present, though less pronounced, 

 in variety I. Variety I was growing in an especially unfavor- 

 able situation and seemed stunted and far from vigorous. One 

 plant, however, stronger than the rest, compared very closely 

 with the members of variety II and variety III. 



2. Distinctions in CoroliLa Diameter and Measurements of 



THE Same 



The distinctions in corolla diameter were most clearly marked 

 as shown in figure 2 on plate 34. This photograph was taken 

 in 1908, but the gradations in size hold good equally well for the 

 years 1910 and 1911. Some three hundred measurements of 

 the corolla diameters of the three varieties were made during 

 August and September. 1910. Corolla diameter is taken to 

 mean the average of two measurements at different angles across 

 the flattened surface of the fully opened salverform corolla limb 

 — (plate 32. A to B and B to C). A flexible celluloid millimeter 

 ruler was used and simply laid on the flower at the two angles 

 and the measurements recorded. The condensed record of these 

 measurements follows : 



Variety Number of Diameter of Diameter of Average all Degree of 



number flowers meas. smallest flower largest flower measurements fluctuation 



I. 108 26 mm. 28 mm. 26.93 mm. 3 mm.* 



II. 131 19 mm. 22 (23?) mm. 20.66 mm. 4 or 5 mm.* 



III. 82 13 mm. 15 mm. 13.98 mm. 3 mm.* 



(* The fluctuation between diameters 13 mm. and 15 mm. amounts, of 

 course, to a difference of but 2 mm. By speaking of the fluctuation as 

 amountiii};- to 3 mm. is meant that corollas of flowers of variety III were 

 meJiMured whieli were found to be 13 mm., 14 nun. and 15 mm. in diameter. 

 The same method of notation for matters of degrees of fluctuation holds 

 throughout in the above table and in similar tables expressing fluctuation 

 in parent and hyl^rid diameters). 



