182 Mr. J. Hardy on the effects produced 



2. Habrothamnus tomentosus, Bth. PI. Hartw. n. 369. 



3. Habrothamnus corymhosus, Eiidl. Bot. Mag. tab. 4201 ; Van 

 Houtte, Flor. ii. tab. 10. Meyenia corymbosay Schl. loc. cit. 

 252. 



4. Habrothamnus cyaneus, Lindl. Bot. Reg. n. s. Misc. 72. 



5. Habrothamnus paniculatu^y Mart. & Gal., Bull. Acad. Brux. xii. 

 148. 



6. Habrothamnus roseus, Mexico. Oestrum roseum, H. B. K. iii. 

 59. tab. 197. 



XVI. — On the effects produced by some Insects, ^c. upon Plants. 

 By James Hardy, Penmanshiel*. 



I DO not intend in tbe present notices to offer any remarks on 

 the general subject of the effects of the Annulosa upon vegeta- 

 tion ; this is a theme too important to be disposed of cursorily, 

 and to follow it out in detail would require a treatise. I design 

 merely to make a few statements relative to some observations 

 recently made on some points, where botany and entomology 

 may be said to be conterminous and capable of affording mutual 

 illustration. 



1. Vibrio Graminis. 



On the 28th of May I noticed that the leaves of the sheep's 

 fescue grass {Festuca ovina), and if I recollect aright, of some 

 other grasses, growing close upon the sea-coast, were affected 

 with several purplish swellings, of which I brought away examples 

 for examination. They only appear a little thicker than the leaf 

 in whose substance they originate, and according to their length 

 are squarish or oblong, slightly roughish, stiff and rounded like 

 a piece of wire, and occupy either the entire breadth or are con- 

 fined to the edges. At first, from finding in the interior only 

 bluish or purplish granules, I felt disposed to attribute them to 

 a fungus ; till opening others more carefully, I observed several 

 minute Ann elides, coiled up in channels winding amongst the 

 granules. These I subsequently found were Vibriones, of which 

 one species, Vibrio Tritici, as is now well understood, produces 

 the disease called '^Ear Cockles," or "Burnt Corn'' in wheat. 

 Others of somewhat similar character swarm in decaying pota- 

 toes and turnips, and the " eel " of vinegar is an example fami- 

 liar to microscopic amateurs. Some of the knots contained only 

 a single occupant, but one of the more elongated ones had about 

 half a dozen of various sizes. The worms are white, almost 

 transparent, very minute and slender, just visible to the eye, 



♦ Read before the Botanical Society of Edinburgh, July 11, 1860. 



