What’s a dichotomous key?
Help
Lespedeza
See list of 13 species in this genusHybrids are occasionally collected in Lespedeza and are most frequent in larger populations that contain two or more species. Though not all hybrids present an easy manner for detecting the type of plant (i.e., if the plant is an orthospecies or a nothospecies), some plants do provide clues as to their origin. Plants with ascending stems in mixed populations of species with procumbent or erect stems are likely hybrids. Plants with pink flowers in mixed populations of species with white or purple flowers are likely hybrids. Native plants with fruits that are shortly exserted from the calyx (i.e., the calyx is ca. ⅔ as long as the fruit) are likely hybrids (given that native species of Lespedeza have fruits that are up to about as long as the calyx or 2 or more times as long as the calyx). References: Clewell (1966), Raveill (2006).
-
1a. Shrubs or suffutescent herbs 10–30 dm tall; corollas 8–15 mm long; stipules persistent
-
2a. Calyx lobes aristate-tipped; leaflets broad-oval, 1–1.3 times as long as wide; inflorescence not or scarcely exceeding the subtending leaves
-
2b. Calyx lobes acute or even mucronate, but not aristate-tipped; leaflets narrow-elliptic to oval, 1.5–3 times as long as wide; inflorescence much exceeding the subtending leaves
-
3a. Corolla 8–11 mm long; calyx lobes acute, shorter than or equal to the length of the basal, connate portion of the calyx; leaflets oval, 1.5–2 times as long as wide; stems solitary or few together from the summit of the root crown, the young stems brown; seeds mottled purple or green
-
3b. Corolla (10–) 12–15 mm long; calyx lobes often mucronate, longer than the basal connate portion of the calyx; leaflets narrow-elliptic to oval, 2–3 times as long as wide; stems many and clustered from the summit of the root crown, the young stems purple; seeds purple-black
-
-
-
1b. Herbs 2–15 (–20) dm tall or long; corollas 5–9 mm long; stipules usually caducous
-
4a. Corollas pink-purple to purple; legume (2–) 2.5–4 times as long as the persistent calyx [Fig. 644]
-
5a. Plants procumbent or trailing
-
6a. Stem and petiole pilose (i.e., pubescent with spreading hairs); primary leaves with broad-ovate leaflets 1.2–2 times as long as wide; racemes with 8–12 (–14) flowers
-
6b. Stem and petiole strigose (i.e., pubescent with ± appressed hairs); primary leaves with elliptic to ovate or obovate leaflets 1.5–2.5 (–3) times as long as wide; racemes with 4–8 (–12) flowers
-
-
5b. Plants erect to ascending
-
7a. Chasmogamous inflorescence loose, with 4–6 (–8) flowers, relatively elongate, the peduncle and rachis combined 2–5 times as long as the subtending leaf [Fig. 642]; keel petal 1–2 mm longer than the wing petals; calyx ca. 20% (rarely as much as 25%) as long as the legume
-
7b. Chasmogamous inflorescence dense, with 4–14 flowers, borne on relatively short peduncles, the peduncle and rachis combined up to 1.5 times as long as the subtending leaf; keel petal up to as long as the wing petals; calyx 20–40% as long as the legume
-
8a. Leaflets oblong to linear, (4–) 5–7 times as long as wide
-
8b. Leaflets elliptic-oblong to broad-elliptic or obovate, 1–3 (–3.5) times as long as wide
-
9a. Leaflets glabrous on the adaxial surface or sometimes strigose along the midrib; upper 2 calyx lobes connate for ca. 50% or more of their length above the basal, tubular portion of the calyx; stems usually strigose
-
9b. Leaflets strigose to pilose on the adaxial surface; upper 2 calyx lobes distinct or shortly connate above the basal, tubular portion of the calyx; stems usually pilose
-
-
-
-
-
4b. Corollas white or ochroleucous, sometimes with a purple spot on the banner petal; legume not or only slightly exceeding the persistent calyx [Fig. 643]
-
10a. Flowers solitary or in clusters of 2 or 3, borne on very short peduncles, the peduncle and rachis combined shorter than the subtending leaf; upper 2 calyx lobes connate ca. 50% of their length; leaflets truncate or retuse at the apex
-
10b. Raceme with 10–44 flowers, relatively elongate, the peduncle and rachis combined 1–3.5 times as long as the subtending leaf; calyx lobes all distinct; leaflets rounded to obtuse at the apex
-
11a. Leaflets ovate-elliptic to obovate, 1.2–1.8 times as long as wide; middle stem leaves borne on petioles 10–15 (–20) mm long
-
11b. Leaflets narrow-oblong to oblong or elliptic, 2.5–8 times as long as wide; middle stem leaves borne on petioles 1–3 (–6) mm long
-
12a. Racemes included in or scarcely exceeding the subtending leaves, with subglobose to short-ovoid clusters of flowers; calyx 8–12 mm long; corolla 8–12 mm long; leaflets elliptic to oblong (rarely narrow-oblong), (2–) 2.5–5 (–8) times as long as wide
-
12b. Racemes exserted beyong the subtending leaves, with ovoid to cylindric clusters of flowers; calyx 5–8 mm long; corolla 5–7 mm long; leaflets elliptic-oblong to narrow-oblong, 4–8 times as long as wide
-
-
-
-
Show photos of:
Each photo represents one species in this genus.