Placed in the Liliaceae in Michigan Flora.
1. Plants with at least some principal leaves clearly borne on the stem above the base; inflorescences paniculate (except in depauperate individuals).
2. Tepals with a conspicuous dark gland below the middle on the inner side; flowers mostly on pedicels longer than the perianth.
2. Tepals glandless; flowers sessile or on pedicels shorter than the perianth.
1. Plants with the principal leaves all basal (at ground level) or nearly so, cauline leaves absent, reduced to bracts, or at most much smaller or fewer than basal leaves; inflorescences racemose.
3. Tepals united for half or more of their length.
3. Tepals completely separate or united at base only.
4. Plants dioecious (flowers unisexual); pedicels not bracted; perianth less than 4 mm long; inflorescence a long narrow spike-like raceme ca. 1–1.5 cm in diameter and 8–30 cm long.
4. Plants with bisexual flowers; pedicels with a bract at the base; inflorescence shorter than 6 cm.
5. Perianth ca. 2–3 mm long, not subtended by bractlets; peduncles and pedicels smooth.
5. Perianth 3–5 (–6) mm long, subtended by tiny bractlets (in addition to the bracts at the bases of the pedicels); peduncle and pedicels glandular-sticky.
All species found in Melanthiaceae
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. July 22, 2017. http://michiganflora.net/family.aspx?id=MELANTHIACEAE.