1908] HARVEY—PRAIRIE-GRASS FORMATION 99 
few days of June. Gaura coccinea, Meriolix serrulata, Psoralea 
esculenta, Hedeoma hispida, and Osmodium molle now progressively 
appear. Though flowering during the transition from vernal to 
estival aspect, these forms reach their maximum display during the 
early estival; particularly is this true of Meriolix, Hedeoma, and 
Osmodium. They should be considered transitional species, which 
appear during the unsettled climatological conditions between the 
vernal and estival periods, and are not specially indicative of either. 
Of subcopious occurrence and largely overtopped by leafy stalks of 
autumnal forms they must be ranked as almost neutral in the floral 
aneet Gaura coccinea is a relict of more xerophytic stages and occurs 
primarily though sparsely in the open association of upper slopes 
and crests. It is an annual and a low and obscure element. It 
bears a few-seeded indehiscent nut of little mobility. Meriolix may 
also be considered as a relict of the xerophytic stages of the prairie, 
having its present distribution limited to the open association along 
“rests and upper slopes, where it frequently occurs subcopiously. 
Its large yellow flowers make it conspicuous, but only at short range, 
. a. stature relegates it to a sublayer. It is a slightly shrubby 
oe from a woody root, producing numerous seeds which are 
floral ek Immobile. It continues blooming up into the autumnal 
is Fire tie = reaches its maximum in the early estival. Psoralea 
inconspicy solitary occurrence on middle slopes; add to this its 
iG E fading-blue flowers and it is scarcely seen upon the 
techies ; . observer. It is a perennial from a large edible 
close to the ” ‘rous root. In the autumnal aspect, breaking off 
lematical Alea It becomes a tumble-weed. Its rarity 1s a 
high, ieee nay a low annual, scarcely ever more than 20° 
middle slo — = oplously and not infrequently copiously upon 
hide its en ts low stature and leafy branches completely 
spicuous, ee small blue flowers, rendering it ever incon- 
the whole ee See Otate sparsely though quite generally over 
@ perennial ae. with the exception of the very crests. It is 
Scorpioid tacem several Stalks, terminated by leafy, pendent, 
It ig ‘a ae es of greenish flowers, arising from a thick root. 
mobility, unnoticeable. The smooth nutlets possess limited 
