~!^4: DO.MATIA IX CERTAIN' AUSTRALIAN AND OTIIEH PLANTS, 



they occur in quite an iudeHnite manner on the under side of the 

 leaf. I cannot assert with positive certainty that these dimples 

 ai*e domatia, but I may commend these particular formations to 

 closer examination by those l^iologists who have the opportunity 

 of studying them in the open." The structures alluded to occur 

 in ((uite a number of plants, e.g., Cedrela auaf.ralis, Acronychia 

 Iceri.-!, and many indigenous Rutacese. They are crater shaped 

 hollows, and when young the edges overhang so as to give a 

 transverse section the appearance of sucli a domatium as is found 

 in Copiosma. But the whole cavity is filled up by a sessile round 

 or elliptical gland, flat-topped, shining with moisture, and pale 

 coloured. Soinetimes in old leaves the gland is wanting, having 

 apparently dried up and fallen out. In Cedrela they sometimes 

 occur on the veins, usually near the top of the leaf, and in one 

 instance I found one in the hair- tufted depression which forms 

 the first stage of a domatium. But ordinarily they occur away 

 from the veins, and I could not find any rule as to the place of 

 their occurrence. Acarids are sometimes found in them. 



"Acacia dealbata, Link. (1, p. 54) has usually red dimples 

 along the rhachis in a row on the upper side. These are most 

 frequently uninhabited as far as I have been able to find. . . . 

 These peculiar formations may well deserve to be closely 

 examined in a natural state." These are most decidedly not 

 domatia, but true secreting glands with a duct to carry off the 

 secretion, which, judging from the fondness of ants for it, is of a 

 sugary nature. 



QuERCUS ROBUR, Liun. — At the base of the leaf, there are two 

 backward curves forming shell-shaped cavities which Dr. Lund- 

 strom takes to be domatia. I tind, as he describes, that there is 

 no structu.re characteristic of domatia. Stomata occur inside, 

 and the inner surface seems to transpire more rapidly than the 

 rest of the leaf, for on several occasions I found this surface 

 covered with a dew of condensed vapour. The interior is always 

 much covered with dust, I found no mites in examining a large 

 number of leaves. 



