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honey-clover, white melilot, white sweet-clover

grand mélilot, tall yellow sweetclover

Habit Herbs usually biennial, rarely annual, 30–150(–260) cm. Herbs biennial or short-lived perennial, 60–160 cm.
Stems

erect or ascending.

erect.

Leaves

stipules lanceolate-subulate to setaceous, 4–6(–10) mm, margins usually entire, sometimes toothed at base;

leaflet blades narrowly oblong-obovate to suborbiculate-oblong, 10–24(–50) × 5–12(–15) mm, margins dentate.

stipules subulate-setaceous, 5–8 mm, margins entire;

leaflet blades linear to lanceolate-oblong, oblong-ovate, or cuneate, 20–40 × 4–10 mm, margins subentire or dentate.

Racemes

40–80(–120)-flowered.

15–50-flowered.

Pedicels

1–1.5(–2) mm.

2 mm.

Flowers

3.5–5(–6) mm;

corolla white;

ovary glabrous.

5–7 mm;

corolla yellow;

ovary appressed-pubescent.

Legumes

obovoid, subglobose, or globose-ovoid, 3–5 mm, reticulate-veined, glabrous.

obovoid or elongated-ellipsoid, 3.5–5(–6) mm, reticulate-veined, areoles not notably elongated transversely, appressed-pubescent.

Seeds

1 or 2(or 3), ovoid, (1.7–)2–2.5(–3.5) mm.

usually 2, ovoid or ellipsoid, 2–2.5 mm.

2n

= 16.

= 16 (Eurasia).

Melilotus albus

Melilotus altissimus

Phenology Flowering spring–fall. Flowering early summer–fall.
Habitat Grasslands, mixed forests, can­yons, streamsides, riverbeds, lakeshores, waste places, roadsides. Waste places, roadsides.
Elevation 0–2700 m. (0–8900 ft.) 0–1000 m. (0–3300 ft.)
Distribution
from FNA
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NL; NS; NT; NU; ON; PE; QC; SK; YT; SPM; Greenland; Eurasia [Introduced in North America; introduced also in Mexico, West Indies, South America, Australia]
[WildflowerSearch map]
from FNA
IL; ME; MI; NJ; NY; OH; PA; WI; NB; NS; ON; Greenland; Europe [Introduced in North America; introduced also in South America, Asia]
[BONAP county map]
Discussion

Melilotus albus is extremely variable in Eurasia, and has been divided into many infraspecific taxa. It is the most important economic species in Melilotus, often grown as a crop, green manure, and honey plant, and posing a widespread weed problem.

Essentially all white-petaled Melilotus plants growing outside of cultivation in North America are M. albus; herbarium specimens often do not show the color well, sometimes resulting in misidentification, particularly between M. albus and M. officinalis. Aside from petal color, the species are quite similar. The venation areolae on the mature pods tend to differ: the raised venation ridges tend to form an irregular reticulation on the mature fruits of M. albus; they tend to form transverse areolae on the fruits of M. officinalis (S. J. Darbyshire and E. Small 2018). Although M. albus and M. officinalis are sometimes merged, there are very strong barriers to interbreeding between the two (G. T. Webster 1955; M. Maekawa et al. 1991), in addition to geographical and ecological differences, which justify their continued recognition as separate species.

P. Coulot and P. Rabaute (2013) included Melilotus albus in Trigonella sulcata (Desfontaines) Coulot & Rabaute (treated here as M. sulcatus). Most botanical literature incorrectly lists the authority for Melilotus albus as Desrousseaux in Lamarck instead of Medikus.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Melilotus Fabaceae > subfam. Faboideae > Melilotus
Sibling taxa
M. altissimus, M. indicus, M. officinalis, M. sulcatus, M. wolgicus
M. albus, M. indicus, M. officinalis, M. sulcatus, M. wolgicus
Synonyms Trigonella altissima
Name authority Medikus: Vorles. Churpfälz. Phys.-Ökon. Ges. 2: 382. (1787) — (as alba) Thuillier: Fl. Env. Paris ed. 2, 378. (1799) — (as altissima)
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