Publication: Vasc. Pl. Wyoming ed. 3. 376. 2001.
selected vouchers: WTU
Notes: FNA7: "Completely glabrous individuals of B. lyallii are sometimes confused with B. davidsonii, but they are easily distinguished by the absence of persistent leaf bases on caudex branches, erect and appressed (versus ascending) fruits, and biseriate to sub-biseriate (versus uniseriate) seeds. Both sexual and apomictic collections are known; further study is needed to determine whether they truly are conspecific."