General description: Thelypodiopsis juniperorum is a slender annual, 3-10 dm tall, with a single erect stem or with several branches arising from the base (Rollins 1993). Payson (1922) wrote that T. juniperorum is an annual or perennial, but all subsequent descriptions have stated that it is only an annual. However, some specimens have rather stout roots and many dead leaves giving them the appearance of a biennial, or perhaps a winter annual. The basal leaves are 5-15 cm long (sometimes smaller), entire or irregularly dentate, with a winged petiole (Rollins 1993). The fruit of T. juniperorum is a silique, which in the Brassicaceae is a long, slender almost terete (round) structure. The ascending siliques of T. juniperorum are approximately 1 mm in diameter and 5-9 cm long (Anderson 2004).

Look Alikes: The most commonly used diagnostic characteristic is the presence of flattened hairs near the base of the stem and at the nodes. This character is useful for distinguishing Thelypodiopsis juniperorum from T. ambigua, which is glabrous throughout. It can be difficult to distinguish Thelypodiopsis juniperorum from T. elegans. The ranges of these species overlap, and T. elegans is highly polymorphic (Rollins 1982, Rollins 1993). Weber and Wittmann (2012) use flower color to distinguish T. juniperorum from T. elegans, noting that T. juniperorum has purple flowers while T. elegans has white to pink flowers. Rollins (1982 and 1993) and Rydberg (1923) also mention only purple flowers for T. juniperorum, but two specimens of T. juniperorum at the Rocky Mountain Herbarium (Payson 97 and Rollins 2110) have purple sepals and white petals. Payson (1922), in describing the species, noted that flowers could be white or purple. The length and thickness of the stipe, a stalk that attaches the fruit to the receptacle, is highly diagnostic in members of the genus Thelypodiopsis, and is used by Rollins (1993) to separate T. juniperorum from T. elegans. The stipe of members of the genus Thelypodiopsis is similar to those seen in members of the genus Stanleya and distinguishes it from many other species in the Brassicaceae. The stipe of T. juniperorum is slender and exceeds 2 mm in length, while that of T. elegans is less than 2 mm or absent, and stout (Rollins 1993). There is often considerable variation in stipe characteristics on single plants of both T. juniperorum and T. elegans, which can make it difficult to identify this species confidently. Payson (1922) notes that T. elegans can sometimes be found within 100 yards of T. juniperorum, but T. elegans is found on barren gypsiferous or “adobe” substrates while T. juniperorum is found in more densely vegetated sites. Thus fine-scale edaphic characteristics are also useful in distinguishing T. juniperorum and T. elegans (Anderson 2004).
 

Phenology: Flowering May thru June (Rollins 1993, Colorado Natural Heritage Program 2012).

This species is found on dry hillsides, sagebrush and juniper areas, below granitic cliffs, rock slides, pinon-juniper woodlands (Rollins 1993).

Elevation Range: 5,771 - 9,534 feet (1,759 - 2,906 meters)

Colorado endemic: Yes
Global range: Colorado endemic; known from Delta, Garfield, Gunnison and Montrose counties.

There are several threats to T. juniperorum based on information presented in the USFS species assessment (Anderson 2004). In order of decreasing priority, these are grazing, off-road vehicle use, non-native species invasion, fire suppression, energy development, residential development, pesticide use for range management, hiking, and global climate change. These threats and the hierarchy ascribed to them are speculative due to a lack of information specific to T. juniperorum. Assessment of threats to this species will be an important component of future inventory and monitoring work (Anderson 2004).