Unground Elm— Unground Elm occurs as broad,flat,oblong pieces from 1to 4mm in thickness.The outer surface is yellow-orange with some brown outer bark or cork layers attached;the inner surface,which is pale yellow,is marked faintly with striated phloem lines.The fracture is fibrous with projections of five bast bundles.

Powdered Elm— Powdered Elm is weak yellowish orange and has a distinctive fenugreek-like odor.Bast fibers are numerous,very long,usually broken,up to 25µm in diameter,thick-walled,unlignified or with only a thin outer sheath of the wall lignified;calcium oxalate prisms from 10to 35µm in length;starch grains spheroidal or polygonal,usually from 3to 15µm in diameter,occasionally up to 25µm in length;and numerous mucilage fragments,frequently lamellated.Cork cells are few or absent.

A: Macerate 1g of finely powdered Elm with 40mLof cold water for 1hour:the mixture is of a thick mucilaginous consistency and yellowish brown in color.

B: Extract 1g of Powdered Elmwith 10mLof 60%methanol on a water bath for about 15minutes,cool,filter,and concentrate the filtrate to about 2.5mL.Separately apply 20µLof this solution and 20µLof a standard solution containing 0.025%rutin in methanol to a thin-layer chromatographic plate coated with a 0.25-mm layer of chromatographic silica gel.Develop the chromatogram in a solvent system consisting of a mixture of ethyl acetate,water,anhydrous formic acid,and glacial acetic acid (100:27:11:11)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the chromatographic chamber,and allow to air-dry.Spray the plate with a 1%solution of 2-aminoethyl diphenylborinate ester in methanol followed by a 5%solution of polyethylene glycol 4000in alcohol,and examine the plate under UVlight at 366nm:the RFvalues of the principal spots relative to rutin are about 1.05(blue)and 0.8(orange).