BULLETIN 



OF THE 



TORREY BOTANICAL CLUB. 



Vol. Vlll.l New York, December 1881. [^o. 12 



134. The Fertilization of Scrophu^laria. 



By William 7'release. 



If one might judge from the number of published accounts, the 

 process of pollination in all its details should be, in few genera, 

 better known than in that which forms the subject of this note. 

 Unfortunately, however, the student who compares these accounts 

 finds that they differ greatly among themselves, while not a few fail 

 to agree with what he observes for himself in studying the plants. 

 For this reason it has been thought not unprofitable to combine an 

 account of some observations made during the past three years by 

 the writer, with a critical summary of the literature that he has had 

 access to. Unless otherwise stated, what is said relates to S> nodosa^ L. 



The tube of the irregular gamopetalous corolla is inflafed approxi- 

 mately to a sphere (Figs, i and 4), its limb projecting from the some- 

 what constricted mouth. The bilobed upper lip and the lateral lobes of 

 the trilobed lower lip project straight forward, giving the flower 

 some resemblance to the old-fashioned poke bonnets one occasion- 

 ally eacounters in country places ; while the middle lobe of the 

 lower lip is reflexed and closely applied to the outside of the tube. 

 This structure, and the color, inconspicuous though it be, of the 

 corolla, lead us to believe the flowers zoophilous, a belief strength- 

 ened by the fact that nectar is abundantly secreted from the expan- 

 sion of the flower until some time after fertilization has been effected. 

 The organ which secretes this fluid is an irregular annular disk 

 which surrounds the base of the ovary (Figs. 2 and 3). Commonly, 

 but not invariably, it is more prominent on the ni)per side ; and 

 unless the quantity of nectar is very great, it collects \\\ one or more 

 drops at the upper side of the ovary, though it has occasionally been 

 found in sufficient quantity to fill the basal part of the corolla. 



When a flower is about to open, its style will be found bent 

 upward, the already mature stigma lying against or close to the top 

 of the corolla, while the four immature stamens are crumpled down 

 into its base, near the ovary. When the flower has opened, these 

 organs retain essentially the same position, the style being so curved 

 that the stigma lies just below the middle of the mouth of the 

 corolla (Fig. 2). In this state the flower is functionally pistillate. 

 After a varying period, depending largely upon the temperature pre- 

 vailing at the time, the stamens begin to appear at the mouth of the 

 corolla, successively taking their f>laces close to the base of the 

 reflexed lobe of the lower lip, and shedding their pollen. A consid- 

 erable number of observations show that the inner (or lower) pair 

 matures first,ih some cases the one on the right appearing first ; in 

 others, that on the left. If, as is constantly the case in pleasant 

 weather, when the insects which will be shown to visit the flowers 

 are most active, the stigma has been fertilized before this, its style 



