29 VARIATION IN ASTER 
ditions of growth of the different plants; except that the reddest 
plants were in the greater shade, a condition usually unfavorable 
to developing red rays in that species, and inducing me to class 
these red-rayed plants as sports, or abnormal. 
DIAGNOSTIC VALUE OF STRUCTURAL ORGANS 
Diagnostic characters which prove serviceable in discriminating 
Aster forms include the following, being characters which often 
remain moderately true and distinct within one or more particular 
forms. 
Predominant leaf-form (of large radicals and of lower caulines). 
Sinus when with cordate base. 
Teeth and acumination of the leaf. 
Upper cauline leaf-form. 
Winged petioles, as to presence, position, form. 
Leaf-color, texture, roughness. 
Color of rays ; of stem ; of disks after turning. 
Pubescence on under leaf-surface, on upper surface, on stem, 
on petiole, on inflorescence. 
Glandular hair, as to presence, parts affected, closeness, form, 
odor and viscidity. 
Angle of branching. 
Inflorescence-form ; density at maturity ; outline produced in 
nature, and again when flattened in drying. 
Heads, as to shape and size. 
Bracts, as to quincunx or triseriate maculation (green tips 
prominent in 3 or 4 rows out of 5 rows of bracts), apex, breadth, 
shape, substance, degree of taper, color, midrib, ciliation, puberu- 
lent surface. 
Rays, in shape and number. 
Green tips, as to form, color, margin, persistence through the 
head, etc. 
COLONY-FORMING CHARACTERS 
Colonies are patches due to root propagation by pale or bright 
smooth slender surculi which become dark thickened rootstocks 
gradually separating by decay. The colonies vary according to 
the species in density, size, permanence and freedom from inter- 
mixture. Within the species the colony habit seems little variable, 
