EVENING PRIMROSE FAMILY ONAGRACEAE 
GAURA 
Gaura biennis L. 
This Gaura is the only species in Illinois. It is a biennial 
herb which grows in rather dry soil from Quebec to Ontario and 
Minnesota, south to Georgia and Arkansas, and blooms from 
July to September. 
\A f The first year it produces a 
YR, ; 
rosette of leaves which manufacture 
SS SS 2 food to be stored in the roots and 
used the following year. The second 
SS. a year it sends up an erect, much 
aa } branched stem 2-5 feet high, covered 
SNA) | with short downy hairs and bearing 
SSQyZF : 
‘\ ‘> ~—Ssailternate sessile leaves. 
y, y The rather loose spikes are pro- 
duced at the ends of branches as well 
as at the terminus of the main stem. 
The flower parts are attached above 
the ovary. The slender calyx tube is 
prolonged beyond the ovary and at 
the summit is divided into 4 rather 
y long, narrow and reflexed lobes. 
ptt The 4 slightly unequal petals are 
A yj (f} white, becoming pink with age. 
Z Petals and the 8 stamens are in- 
serted on the throat of the calyx 
tube. Stamens and the slender style 
are at first turned down. The sta- 
mens straighten as the anthers ma- 
ture, and after the pollen has been 
discharged or nearly so the style 
\ straightens and the 4-lobed stigma, 
' closed and surrounded by a cuplike 
ring, opens. The 4-ribbed nutlike 
fruit is acute at both ends, less than one-quarter inch long, 
covered with soft hairs and contains 1-4 seeds. 
Because the flowers are quite small and not a vivid color, the 
name Gaura, which comes from a Greek word meaning superb, 
seems not to characterize our species very well. 
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