MALLOW FAMILY MALVACEAE 
FLOWER OF AN HOUR 
Hibiscus Trionum L. 
The Rose Mallows described on the preceding pages are 
rather shy plants, but the Flower of an Hour, belonging to the 
same genus, is much bolder and dwells in places frequented by 
man, such as road- 
sides, the edges of 
cornfields and other 
waste or cultivated 
places. This species 
is a native of south- 
ern Europe but it 
seems to like America 
very well and is now 
found from Nova 
Scotia to Florida and 
west to South Da- 
kota and Kansas. 
It is a low annual which branches 
from the base and spreads over the 
ground. The whole plant is covered 
with spreading hairs and the leaves 
are 3-7-lobed or divided, the obtuse 
lobes round toothed or cleft, and 
the middle one longest. 
3 During the blooming season of 
August and September the Flower of an Hour opens for only a 
short while in the morning, thus acquiring its common name. 
The flowers, produced in the axils of the upper leaves, are sulfur 
yellow with a dark purple center, and the outer edges of the 
petals are tinged purple also. The involucel of many narrow 
bractlets is much shorter than the beautifully veined, inflated 
calyx, which is 5-lobed and s-angled. The numerous stamens 
are united into a column around the compound pistil and the 
style has 5 branches at the end, each branch bearing a stigma. 
The fruit is a hairy, nearly spherical, several-seeded capsule. 
The Rose of Sharon, Hibiscus syriacus L., is a southern plant 
which frequents rocky soil near streams. It is a tall, smooth shrub 
with wedge-shaped to ovate, pointed and cut-toothed or lobed leaves. 
The flowers, pink or white with a crimson center, bloom from July 
to September. 
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