Leucoanthocyallins ill plant tissues have been estimated by moasuring tho nnthocyanidins produced after hoating with i8opropanol-hydroehloric acid in it closo(1 tuhe. Various tiSSllOS of fiJucalYT!tu8 sicberiarla F. Muoll., E. obZiqua I,'Horit., E. regnan8 F. Muol!., and Ii). maculata Hoole were studied by this method. The amonnt of loucoanthoeyanills was observed to decrease with increasing degree of maturity of tho dif'fel'Ollt leaves on a stem. il<fost of the leucoanthocyanins appeared to be in tho colourless leaf tips. Tho amount of lellcoanthocyanin in the bnrk decrcascd during the growing season, ntHl the amount in the emnhimn decreasod rapidly once difforontiation of MiO tissnes began. 1'ho sapwood of E. 8"ieber-iana containcd about half that in the heartwood. Similar results wore found in transvcrsc discs from logs of E. marg'inat(t Sm. which contained also an outer heartwood zOlle. 1'ho extraneous materials'in this lattcr zone were lllllCh ]"nore water soluble, although Lho alkali solublos of tho inner outm' hoartwood zonos werc tho smne. Tho acctono solublos ill E. mar-irinata sapwood wel'e lnrgoly leucoallthocyanins.