119 

 Botanical N'otes. 



By Mosks N. Elrod. 



Tecoma radicans (L.) D (J. The trumpet-flower presents many peculiar 

 characters that are of great vahie hi securing cross-fertilization, and it 

 seems to be constructed on a plan admirably adapted to meet the needs 

 of the humming-bird. 



One among the first things in its structure to attract attention is tlie 

 nearly horizontal position of the flower, its short, unexpanded lower lip, 

 the opposite of the arrangement in many flowers dependent upon insect 

 visitors for fertilization, and the manner in which the filaments are 

 twisted right and left so as to bring the dehiscing anther on the same 

 plane with their backs against the upper lip of the corolla. This group- 

 ing of the anthers is eff'ected by the outer and longer pair of the angular, 

 (linidrphous filaments making one turn on their axes and the inner pair 

 making a half turn. The pistil is a little longer than the stamens and 

 terminates in a two-branched, foliaceous, spatulate stigma. 



In July, 1002, I noticed that the stigma is sensitive. While searcliing 

 in my pocket for a magnifying glass the lo'oes of a plucked flower had 

 closed so that the stigmatic surfaces were in close contact. The use of 

 force failed to separate them for more than a moment and when one of 

 tlie thin lol)es was cut away the otlier curled up into a loose roll. At the 

 time, 1 supposed that I had made a discovery. Init soon fo\ind that I had 

 been anticipated. In Miiller's "Fertilization of Flowers" it is stated that 

 when tlie stigma of Bifinoula has been "touched by an insect visitor they 

 then close up immediately." He also quotes the experiments of his brother 

 on a South American species, showing that successful fertilization was 

 secured only when the pollen applied came from a plant growing "at a 

 distance." It was to test the sensitiveness of the stigmas and the condi- 

 tions under which cross-fertilization was effectual that my observations of 

 Tecoma radicans were made. 



The stigmatic lobes of a flower which had just come into bloom, when 

 irritated with the point of a knife-blade or any other hard sul)stance, 

 closed in five seconds, and those of the faded flowers in thirty seconds.. 

 A drop of water acted as an irritant when applied soon after the stigmas. 



