50 THE AMERICAN' BOTANIST, 



Ver3^ common among plants is the presence of gladular 

 hairs or jjubescence, like on Petunia viohicea, Martynia 

 Louisiana, Polanisia graveolens, Silene Virginica and 

 Cypripedium acaule. Punctate glands in the leaf blade 

 and other parts are also abundant as in Xanthoxylum 

 Americanum, Polygonum punctatum, Amorpha fruti- 

 cosa, Hypericum perforatum and Boehera papposa. The 

 latter has comparatively large, yellow, oval glands which 

 are very conspicuous under a hand lens. Various plants 

 also have glutinous leaves especially when young, but 

 these will not be considered here. 



Of plants which have glandular surfaces with diges- 

 tive secretions especially concerned in capturing and ab- 

 sorbing other organisms as food, we have the following: 



1. Sarracenia purpurea. 6. Utricularia intermedia. 



2. Drosera rotundifolia. 7. Utricularia minor. 



3. Drosera intermedia. 8. Utricularia gibba. 



4. Utricularia cornuta. 9. Dipsacus S3dvestris. 



5. Utricularia vulgaris. 10. Silphium perfoliatum. 

 In this group probably belong such plants like Silene 

 antirrhina with glutinous bands around the stem and 

 Carduus undulatus, a western species, in which the outer 

 surface of the involucral bracts are very glutinous and 

 catch large numbers of ants which attempt to reach the 

 flowers aboA^e, as well as small flying insects. It seems 

 reasonable to suppose that thedel3ris from these decaj'ing 

 insects may serve as food to the captor. Some of the Ohio 

 thistles also have glandular involucral bracts. 



Various plants have gland tipped teeth or serrations, 

 as species of Salix, Populus, Prunus and other genera. In 

 some plants the stipules have prominent nectar glands or 

 are reduced to nectaries. Other gland-like sti])ules, how- 

 ever, do not appear to secrete nectar. Among the genera 

 which contain species with glandular or gland-like stip- 

 ules, the following may be mentioned : Reseda, Linum, 

 Euphorbia, Isnardia and Circsea. 



The more important glands of special interest are 

 those which secrete nectar or those which have attained 



