758 



ON DOMATIA IN CERTAIN AUSTRALIAN AND 

 OTHER PLANTS. 



By Alex. G. Hamilton. 



(Plate Lvii.) 



Some years ago, when collecting Fennontia Cunninghamii, 

 Miers, my attention was attracted by the presence of prominences 

 on the upper surface of the leaves which I at tirst took to be the 

 nidus of some leaf-mining insect larva. But further observation 

 showed that they always had an opening on the under surface of 

 the leaf, and invariably occurred in the same position, viz., in the 

 axils of the veins. A short time after, I happened to look at the 

 leaves of the ornamental New Zealand shrub, Coprosma lucidn, 

 commonly cultivated in gardens, and I was much interested to 

 notice in this plant also the presence of cavities opening to the 

 exterior by conspicuous pores on the lower surface of the leaf. 

 After this I began to examine the leaves of the plants within 

 reach more systematically. 



No books that I was able to consult seemed to throw any light 

 on the subject, and as I am distant from libraries, I w^as glad to 

 make known my needs to several Sydney friends who were at 

 length successful in giving me a clue. 



The first important intelligence came from Mr. E. Betche, who 

 sent me the following quotation from Dr. R. Schumann's article 

 on Rubiacefe, in Engler's " Natui'liche Pflanzenfamilien': — "In 

 den Nervenachseln auf der Riickseite der B. befinden sich zuweilen 

 Haarbuschel, welche eine etwas eingedriickte Stelle der Blatt- 

 spreite umwachsen ; man nannte diese Stellen Blatt-scropheln 

 (Scrobiculai) gegenwartig werden sie als Domatien bezeichnet. 

 Sie sind fur gewisse Arten von Cinchona zur Unterscheidung 

 benutzt worden." 



The next difficulty encountered was to find definitions of sci"0- 

 bicula and domatium. Eventually Mr. J. J. Fletcher found in 

 Henslow's "Floral Structures" (p. 115) a reference to Dr. Lund- 



