108 Observations concernhig 



I have already referred, I have, 1 fear, fallen into an error 

 concerning the Ke-rhnn Oleander, or connnon Rosebay. 

 My words are these : " It has long been known that this 

 is a poisonous plant. But I do not know that any per- 

 son than nivself has observed that this fine vegetable proves 

 very destructive to the common house-flies. These insects 

 visit the Oleander, in order to drink the fluid secreted in 

 the tube of its (lowers. The liquor soon intoxicates them, 

 and verv few of those which have gained admittance into 

 the blossom ever return from it. So great is the number 

 of flies destroyed in the course of one season bv a single 

 Oleander, that I have often thoutiht it would be worth our 

 while to pay more aliention, than we vet do, to the cul- 

 tivation of this vegeta!)le ; as, independently of its beauty, 

 it is so well calculated to lessen the numbers of a most 

 common and troublesome insect." 



Subsequent and more cautious inquiries have convinced 

 me, that althouch the nectareous fluid of the Oleander may 

 prove deleterious to flies, vet that the greater number of 

 the insects which are observed (\c3i.\ or dying, in the flowers 

 of this plant, have been entrapped by the irritability of the 

 (renitalia; by a mechanism, at least, as truly irritable as 

 that bv which insects arc detained in the flowers of the dif- 

 ferent species of Asclepias, oi ylpocynum, and other similar 

 plants. 



In the course of my inquiries and labours concerning 

 the indiscnous plants of the United States, I have had the 

 additional satisCaction of remarking, that one of ourGrasscs 

 is also a ]\lmcicQpa, or at least a catcher of small insects 

 of various kinds. And, so far as I. know, it is the only 

 nrass, hitherto discovered, that is entitled to the name of a 

 Mnscicapa. 



The cra#s to wh.ich I allude is the Lcersia lent'icnlaris 

 of the late Mr. A. Michaux*'. This plant is a native of 

 the marshy grounds of the Illinois country, of Virginia, 

 North Carolina. &c. I do not know that it has been 

 found in Pennsylvania. The glume or coiolla consists of 

 two valves, a character which belongs to all the species of 

 the t'enus Leersia. In the Leersia which is the subject of 

 my observations, the glume is of an orbicular form, mclin- 

 ju"- to lenticular, and is much larger than in any of the 

 other American species that arc known to me, or than it 



* I.eersia {lr"!ini!nri:i] p.-ir.iou'x ramulii «iil)s(ilitaiiis, mmi!Iis scciindarils 

 imbrirHtim .^.picinoris: jjluini.-. lenticiilari-orbictilulii.-, conspicue ciliatis, ma- 

 Tusculis. — Fiiira Bvu uii- ArnLruanu, &c torn. i. p. ;>9. 



is 



