Leaves of asclepias linaria
resemble those of a pine tree; narrow, needle-like, crowed all along the stem, and pointing in all directions. Leaf margins are rolled under, and are lined with a few short hairs, most noticeable on young growth. Leaf tips taper to a sharp point.
The plant can bloom any time of year, reflecting its habitat of sunny, desert areas in central and south Arizona, but the peak months are from April to August. Flowers are produced in several clusters, at or near the top of the stems, each typically containing 10 to 20 heads. The flowers, which are attached by stalks of around one inch in length, are formed of a five-lobed calyx below a five-lobed corolla, white with purple streaks, while at the center are five similarly colored hoods, each enclosing a short white horn, generally not exserted. When fully mature both the calyx and corolla lobes are reflexed. Fruits are bulbous green follicles.