40 



€ 



PERSISTENTSEPAL YELLOWCRESS 

 ( Rorippa calycina ) 



A. CLASSIFICATION 



1. FAMILY: Mustard Family (Brassicaceae) 



2. GENUS: Rorippa possibly refers to the wetland affinity and 

 the curved shape of the fruit (G. ror - dew; G. ipa - worm). 



3. SPECIES: The species epithet refers to the calyx (sepals) 

 as they persist after flowering. 



B. PRESENT LEGAL OR OTHER FORMAL STATUS 



1. FEDERAL STATUS 



a. U.S. FISH AND WILDLIFE SERVICE: 02, a candidate for listing 

 as threatened or endangered (FR NOR 30 Sept. 1993). The 

 only report on this species was prepared in Wyoming in 1981 

 and recommended that it be kept as a candidate for further 

 study (Lichvar 1981) . It has subsequently been recommended 

 dropped from consideration (30) based on additional field 

 surveys documenting new populations in Wyoming, high 

 relative numbers and relative lack of threats (Fertig pers. 

 commun. ) . 



b. BUREAU OF LAND MANAGEMENT: proposed watch (BLM 1993) 



2. STATE: The state rank is SI (critically imperiled) based on 

 five records (three historic) in Montana. The two recent 

 records are possibly extirpated. 



C. DESCRIPTION 



1. GENERAL NONTECHNICAL DESCRIPTION: Persistentsepal 



yellowcress is a perennial upright or declining herb, 1-4 dm 

 (4-16 in) tall. The stems and leaves are moderately to 

 densely hairy, especially on the leaf midrib, with long, 

 slender hairs. Leaves are sessile, partly clasping at the 

 base, oblong to oblanceolate, and shallowly to deeply lobed. 

 The infloresence is a raceme growing in both leaf axils and 

 at stem tips. Flowers are bright yellow, with petals 2-3.7 

 mm (.08-. 15 in) long, to 1 mm (.04 in) longer than sepals. 

 Sepals are yellowish-green and persist with fruit. Siliques 

 are globose to subglobose, 2.3-3.4 mm (.09-. 13 in) long, 

 1.2-2.3 mm (.05-. 09 in) wide, ca. 1.2-2X longer than wide, 

 and densely hairy with hairs that are broadened at the base 

 and pointed at the tip. Pedicels curve downward, sometimes! 

 giving the infloresence a one-sided appearance. 



