MALLOW FAMILY MALVACEAE 
PRICKLY SIDA 
Sida spinosa L. 
The specific name of this plant comes from the occur- 
rence of a little pointed tubercle at the base of each of the 
larger leaves, but it is somewhat inept, for this protuber- 
ance, though solid, can hardly be 
called a spine and the plant is not 
really prickly. 
The Prickly Sida is native 
throughout tropical America and has 
spread northward to Maine, Michi- 
gan, southern Wisconsin 
and Iowa. It is the only 
. Sida in Illinois. It isa 
much branched, finely 
and softly hairy annual 
which grows 1-2 feet high 
and produces small yellow flowers all 
summer. 
The flowers open for only a few 
hours in the morning. The calyx is 
s-toothed and naked at the base; 
that is, there is no involucel. The 
corolla consists of 5 yellow petals 
which are usually slightly 1-sided 
C but entire. The numerous stamens 
form a column which bears anthers 
only at the top. There are 5 pistils 
grown together to form a compound ovary but the ¢ styles are 
distinct. The s-parted fruit is within the persistent calyx and 
each part splits at the top into 2 beaks so that the fruit becomes 
10-beaked. Each division of the fruit contains 1 seed. 
__The Poppy Mallow, Callirhoé involucrata (T. & G.) Gray, is a 
diffuse spreading herb of sandy areas, blooming from April to August. 
Its palmately 5-9-lobed leaves, with conspicuous, ovate, persistent 
stipules, are alternately arranged and on medium, long-haired 
petioles. The hairy upper stems and branches end in long hairy 
peduncles terminated by solitary red-purple flowers 2 inches in 
diameter. Sepals and petals are 5, and the pistils are indefinite. This 
is a common annual weed from Massachusetts to Michigan, Kansas 
and southwestward. 
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