American Beautyberry (Callicarpa americana) is a shrub that grows in the southeastern United States. The identifying features includes long green branches with green foliage, expect in the fall when the leaves turn yellow. The distinguishing feature is the bright, glossy purple berries that grow in clusters and can be seen in fall and winter.
This plant was used by several Native American tribes to treat ailments. The leaves and berries were boiled and used to treat fevers, stomachaches, dizziness, and colic. The crushed leaves can also act as a mosquito repellant, which is very useful for Austin this time of year!
The berries are a major food source for songbirds and small mammals. Deer will eat the leaves because of their high protein count. American beautyberry is a pioneer species making it a useful tool for forest rehabilitation. My iNaturalist post is here.
References:
http://www.wildflower.org/plants/result.php?id_plant=CAAM2
https://plants.usda.gov/factsheet/pdf/fs_caam2.pdf