TECOMA RADICANS. TRUMPET-FLOWER. 7 



The reference to the sensitive lobes of the stigma brings be- 

 fore us the question of cross-fertiHzation by insect agency, to 

 which this sensitiveness in some flowers has been supposed to 

 have some relation. It is believed that an insect, in search of 

 honey, with pollen on its back, would rub against the expanded 

 lobes, which would close before the insect left the flower, thus 

 preventing the reception of its own pollen. In the case of our 

 Trumpet-flower, the lobes close very slowly. In cases observed 

 by the author, they were not completely closed in thirty seconds. 

 The bumble-bee visits the flow'er only for pollen, so far as the 

 writer can trace. The flower is barely open before the pollen 

 sacs burst, and these are immediately rifled of their contents. 

 The lobes do not expand till after the bees cease their visits, but a 

 portion of the pollen falls on the stigma as the sacs open, and a 

 few grains may find admittance to the stigmatic surfaces through 

 the clefts as the lobes open. Humming-birds enter the flowers 

 for their sweets, occupying from five to ten seconds in each 

 flower. It is possible they may aid in cross-fertilization, but the 

 author has never been able from actual observation to trace just 

 how much, if any, aid may be derived from this source. It is 

 very likely that some phase of nutrition affects productiveness 

 rather than matters connected with pollen from other flowers, for 

 in Pennsylvania we find it is only the flowers which open latest 

 that usually produce seed, as we see in our Fig. 4, where all the 

 early flowers were infertile. In the plants observed by the 

 writer, large numbers of flowers are often seen with the tubular 

 portions split, as in Fig. 3, but by what agency he has never 

 clearly discovered. 



Our drawing is from its most northern locality, near Phila- 

 delphia, but it is seen in its greatest beauty in the rich alluvial 

 soils along rivers in the Southern States. A lovely sight in 

 a piece of rich woods along the Missouri river, above St. Louis, 

 in which these flowers figured chiefly will ever be remembered. 

 Southwardly from the Gulf of Mexico 



