30 BOTANICAL GAZETTE [JANUARY 
1G. 11.—Tangential section of foliar ray of H. tuberosus, showing more 
advanced Cain of foliar ray in more advanced herb; ray is broader, leaf 
trace i ie and structure more homogeneous than in fig. 10, which has same 
degree of magnification. 
Fic. 12.—Foliar ray of H. annuus, very marked herbaceous species of the 
genus; magnification same as in two preceding figures, and shows that leaf 
trace is much larger, as is also the accompanying ray, which is further marked 
by a much greater advance toward homogeneity than two foregoing figures. 
Fic. 13.—Part of fig. 12, more highly magnified to show presence of some 
degree of variety in elements composing foliar ray; magnification same as 
fig. 9, of Helianthus tuberosus. 
Fic. 1 agnified view of part of fig. 10, representing ray of H. hirsutus; 
for nitrate of comparison magnification is identical with figs. 9 and 13. 
PLATE III 
Fic. 15.—Transverse section of one of angles of upper region of aerial 
stem of Helianthus tuberosus, showing leaf trace in center flanked by stem 
bundles on either hand. 
Fic. 16. Right hand stem bundle of last figure, more highly masniie’, 
to ged presence of cambial activity between xylem and phloe a 
17.—Transverse section of leaf trace in fig. 15, more highly magnified 
to hoe absence of cambial activity in foliar strand. 
Fic. 18.—Transverse section of mature root of Aster Shortii, showing 
pentarchous COME with well developed secondary growth; root hairs 
have disappeare 
Fic. ingest section of younger root of A. Shortii, about phase 
when secondary growth is beginning; root hairs still present but beginning 
to wither away. 
Fic. 20.—Transverse section of persistently hairy root of Asier umbellatus; 
continued presence of root hairs correlated with absence of secondary growth. 
PLATE IV 
Fic. 21.—Transverse section of very herbaceous species of Aster, A. 
tataricus; normal woody structure of Aster replaced by herbaceous texture and 
by more foliar traces (7) than those usually present in species of the genus (3). 
Fic. 22.—Transverse section of small branching stem of Ranunculus acris. 
Fic. 23.—Transverse section of nodal region of larger branching stem of 
R. acris. - 
Fic. 24.—Transverse section of stem of R. acris, below node; 5 foliar traces 
in axis appear darker than stem bundles by reason of their vessels being 
occupied by gummosis. 
Fic. 25.—Part of section similar to that shown in fig. 24, more highly 
—— to show characteristic difference between foliar and cauline bundles. 
Fic. 26.—Another of the same, showing different bundles. 
