128 



THE PLANT WORLD 



midrib near its base on the under side of the leaf. Then I thought I 

 would examine my other malvaceous plants to see if they had correspond- 

 ing glands. In the Sida I found no indication of a gland, but in the 

 Paritium leaves there was a long clean-cut slit in each of the midribs be- 

 neath, corresponding to the gland in the Urena. On some of the leaves of 

 Thespesia popiihiea there was not a vestige of a gland, on others there was 

 a glandular pore between the bases of the veins beneath. Turning to the 

 leguminous plants I found on the leaves of the Erythrina distinct cup- 

 shaped glands on the rachis at the base of the two lower leaflets and in- 



Fig. I. Leaf of /'a>'jVi'«;«^//mC6«w (on the left) showing slit-like gland near base of midrib. Fig. 2. Leaf of Urena 

 sinuata (on the right) showing similar gland in same position. Original. 



dications of glands on each side of the termination of the rachis just be- 

 low the articulation of the terminal leaflet. I had often before noticed 

 the glands on the various species of Cassia and I longed for literature on 

 the subject. Here in Guam I have only Darwin's ' ' Cross and Self Fertilis- 

 ation in the Vegetable Kingdom," and to this I turn. Darwin speaks of 

 plants bearing glands on their leaves, petioles, phyllodia, stipules, brac- 

 teae, or flower peduncles, and sometimes on the outside of the calyx, and 

 these glands secrete minute drops of a sweet fluid which attracts sugar- 

 loving insects, such as ants, hive-bees, and wasps. The question is 



