Salazaria mexicana or Scutellaria mexicana, which is commonly known as the bladder sage or paperbag bush, is a shrub of the mint family Lamiaceae, with many woody, branched, overlapping stems bearing small, greyish-green leaves at opposite intervals.
It is remarkable for its distinctive calyx lobes that develop into small bag- or bladder-like shells around the fruits and its unusual flowers.
It is widespread in sandy and gravelly slopes, desert dry washes, and canyons in the southwestern deserts of North America, including in creosote bush scrub and Joshua tree woodland plant communities in the Mojave, Sonoran and Chihuahuan Deserts in southern California, Nevada, southwestern Utah, Arizona, western Texas, Chihuahua, Sonora, and Baja California.
These bushes often grow intermixed with other shrubs. They are relatively common; although both the foliage and flowers are sparse. Their distinctive pattern of bags makes them easy to spot from a distance.
This plant takes the form of a rounded shrub, typically twenty inches to forty inches high, sometimes larger.
The stems form a spreading rigid pattern, with the tips often becoming spine-like. The branching pattern is distinctive, with opposite side branches forming right angles to the main stem. The plant is drought deciduous, that is, it drops its leaves in dry conditions
The leaves are opposite, small, 3–15 mm long and 2–8 mm wide, ovate to elliptic, have smooth edges, and with a very short or nonexistent petiole.
The flowers have an upper lip which is white or very pale purple in color and shaped like a hood, plus an intense purple lower lip, divided into three lobes. The upper lip has an even covering of short hairs.
The calyx below the corolla is reddish purple at first, and traditionally shaped, but gradually lightens in color as it ages and becomes inflated, widest towards the base, expanding into its distinctive bag shape, 1–2 cm across, the dried flower eventually falling out of the hole in the end.
The fruit inside the dried calyx bags is composed of four nutlets. The plant drops its leaves in dry conditions. The dried bags help with seed dispersal by wind. Flowering is generally April through June, but the bags are durable and may last on the plant into winter, becoming dry and papery.
The plant is rather delicate, though able to continue to grow, if not thrive, under very dry conditions, such as with less than two inches of rain per year. The plant under such parched conditions can become ethereal or ghostly in appearance.
The genus is named after astronomer José Salazar y Larregui, Mexican commissioner for the United States and Mexican Boundary Survey of 1848-55.