40 



rigida of Willdenow, a beautiful species of extreme rarity, 

 form those referred to, as being more or less known. 



Those which are evidently new, are the following — 



72. QUERCUS mannifera (Robora) ; ramulis glabris, foliis petiolatis oblongis 

 subcordatis incisis lobis obtusis supra glabris subtus pubescentibus, 

 gemmis foemineis ovalibus sessilibus aggregatis imbricatis glabris. 



Although no acorns or cups are present on the specimens, 

 no doubt can, I think, be entertained that this plant is speci- 

 fically distinct from our Q. sessilifioi^a, with which alone it 

 can be confounded. The leaves are much thinner and larger ; 

 and their petioles and veins exhibit no trace of the yellowness 

 so characteristic of our own wild plant. It derives its name 

 from the following circumstance, which I give in the words 

 of Mr. Brant. 



" The Koordistan Manna oozes from the upper surface of 

 the leaves of this oak, during the hottest months of the year. 

 The natives cut the branches and steep them in boiling water 

 until the manna is entirely dissolved ; they are then taken 

 out, and the fluid evaporated to the consistence of thick 

 honey. When cool it is shaped into flat round cakes, which 

 are sold as a sweetmeat. The trees produce it only every 

 fourth or fifth year ; no galls are gathered from them ; and 

 I was told that it had no purgative properties. An Arme- 

 nian doctor at Van informed me that he had frequently pre- 

 scribed it to nurses to promote the flow of milk : the largest 

 dose administered by him at a time was of 71 drams avoirdu- 

 pois. The natives call it Ghezen-ghevee, Ghiok-helvahsee, 

 and Koodret-helvahsee ; and from the circumstance of its 

 being found on the upper surface of the leaves, as well as 

 upon stones, pretend that it drops from the sky j hence the 

 appellation of " Ghiok-helvahsee" (the sweetmeat of heaven). 



" The Willows at Van, while I was there, were covered 

 with a syrupy fluid, which in taste and appearance exactly 

 resembled the Oak- manna ; and the Doctor said that it was 

 the production of a small insect (I believe a species of bug), 

 which was common on these trees." 



The manna itself, of which I have received a good quantity, 

 is much mixed with impurities, but it has a very sweet 

 taste, with the mucilaginous quality of gum, and the stickiness 

 of boiled sugar. What its chemical composition may be, 

 will I hope be ascertained by my friend, Mr. Edward Solly, 



