322 XEW EXGLAXD TREES IX \V1XTEE. 



wliL'ii tlu'v ai'c twistcil togcthei' into a move ov less felt-like mass, 

 Imt these (listinetions eanuot lie always sharply drawn. A twig 

 if snioiitli may lie dull or shiny in api)earanee. The leiitieels are of 

 iiiiist ilistincti\-e \alue in those forms like the Kirehe- (]i. 423), in 

 \\'hK-h thev Ijeeiime lairizoiitally elongated with age. The color, 

 size and shape of the pith are often eharaeteristic as seen iu the 

 wide salmon-colored pith of the Iventneky Coffee Tree (p. .~il5) 

 and the star-s]ia|ied pitli nf the Oaks and to a less degree in tlie 

 Poplars (iig. .") ) . Sdiiie few trees have their pitli sejiarated hy 

 linllow ehamliers siieh as tlie Haekliei'ry and the fititteruut 

 ( hg. (i) or have solid i)ith Ijut witli woody cross pai'titious such as 

 the Tupelo. 



T^KAF-SCATiS — The arrangement of the leaf-scars form 

 primary di\'isions in the classification. They may be opposite with 

 two scars at a node as in the Horse-ehestntit. or oltcnuitr with only 

 one scar at the node as in the majoritv of species. Alternate leaf- 

 scars mav he arranged along the twig iu two longitudinal rows 

 when they are said to he J-roul'ed. as iri the ]\Iulherry (fig. 8), 

 or ill several rows when thev are more tlian 2-niiil'ed as iu the 

 Poplars (fig. .3). 'J'wigs soiuetimes if rapidly grown have the 

 leaf-scars Mdiicli arc normally opposite pidled apart to appear 

 alternate, hut the typical condition will l,)e found on other parts of 

 the tree. A few species like the Chestnut sometimes take the 

 2-ranked. an^l sometimes the more than 2-ranked position, and the 

 numljcr of ranks in other forms may be at times somewhat ob- 

 scured by a twisting of the twig. The distinctions in the main, 

 ]iowe\'er, hold good and where a doubt is likel\' to occur in regard 

 to the arrangement, a place has been made in tlie key for the 

 species in both the 2-raiiked and the more than 2-i-anked groups. 



The size and shape of leaf-scars are important fact(n's in identi- 

 fication. 'They may lie very narrow as iu the Pear and 

 their upper margins may Ijc fiat oi- con\ ex as in the Black Ash 

 (p. 561) or deeply notched as iu the White Ash (p. .357) 

 or form a baud nearly surrounding the bud as in the S\-camore 

 (p. 48.')). They may become dingy and inconspicuous or be 

 sharply distinct jjy color contrast with the rest of the twig. Thus 

 the h]lnis and the Poplars ha\e their leaf-scars covereil -with a 

 ligiit-coloix'd coi'k-like layer which makes them consihcuous 



