Km. Snyder et al., COMPARATIVE ECOLOGY OF THE NARROW ENDEMIC ECHINACEA-TENNESSEENSIS AND2 GEOGRAPHICALLY WIDESPREAD CONGENERS - RELATIVE COMPETITIVE ABILITY AND GROWTH-CHARACTERISTICS, International journal of plant sciences, 155(1), 1994, pp. 57-65
Using a multiple de Wit replacement series, we tested the hypothesis t
hat the middle Tennessee cedar glade endemic, Echinacea tennesseensis,
is a poor competitor compared with its geographically widespread clos
e relatives, Echinacea angustifolia var. angustifolia and Echinacea pa
llida. In the competition experiment, all pairwise combinations of the
three Echinacea taxa were grown under greenhouse conditions at severa
l densities and proportions for 175 d. Classical and functional growth
analyses were performed on the three taxa to quantify physiological a
nd morphological characteristics that influence competitive ability. T
he hierarchy of competitive ability (based on relative yield and aggre
ssivity), plant dry mass, and leaf area was E. pallida > E. tennesseen
sis > E. angustifolia. However, neither relative growth rate, net assi
milation rate, leaf area ratio, nor specific leaf weight differed sign
ificantly among the three species (protected least significant differe
nce [PLSD], P > .05). We conclude that lack of competitive ability per
se cannot account for the narrow endemism of E. tennesseensis.