Melilotus
Melilotus indicus
melilot, sweet-clover
annual yellow or Indian or small-flower sweet-clover, annual yellow sweet-clover, Indian sweet-clover, small-flower melilot, small-flower sweet clover, small-flower yellow sweet-clover, sour clover, yellow sweetclover
usually erect or ascending, sometimes decumbent, glabrous or glabrescent.
erect or ascending.
alternate, odd-pinnate;
stipules present, adnate to petiole;
petiolate;
leaflets 3, blade margins usually dentate, rarely entire or subentire, surfaces glabrous or pubescent.
stipules lanceolate-subulate to setaceous, (3–)4–6(–8) mm, margins subentire (entire or toothed at base);
leaflet blades lanceolate-oblong, oblanceolate, or obovate, (8–)12–25 × (2–)7–10 mm, margins dentate.
10–50-flowered.
pedunculate, (5–)8–80(–120)-flowered, axillary, racemes, usually elongating in fruit;
bracts present or absent.
1 mm.
papilionaceous, usually pendulous, sometimes upright;
calyx campanulate, lobes 5, ± subequal;
corolla yellow or white;
stamens 10, diadelphous;
anthers basifixed.
1.5–3 mm;
corolla yellow;
ovary glabrous.
legumes, stipitate, usually ± compressed, usually globose, subglobose, obovoid, or ovoid, sometimes lanceolate-rhomboid or elongated-elliptic, indehiscent or tardily dehiscent, reticulately or concentrically patterned with raised venation, thickly leathery, usually glabrous (pubescent in M. altissimus).
subglobose, 1.5–3(–4) mm, strongly reticulate-veined, glabrous.
1 or 2 (or 3)[–5], usually ovoid, obovoid, oblong to subglobose, or ellipsoid, smooth or slightly tuberculate.
1 (or 2), ovoid, 1.8–2.3 mm.
= 8.
= 16 [18 (Asia)].
Melilotus
Melilotus indicus
Species ca. 18 (6 in the flora).
Trigonella and Melilotus may merit amalgamation (P. Coulot and P. Rabaute 2013), and Melilotus has been subdivided in various ways (reviewed by G. A. Stevenson 1969). Most species of Melilotus have a characteristic vanillalike odor and a bitter taste, due to the presence of coumarins.
Some species of Melilotus are cultivated as forage crops, for soil improvement, erosion control, revegetation and reclamation plantings, and as honey plants. Some are significant weeds, including the cultivated species.
Some Melilotus specimens at GH and NY were collected from ballast sites and have been identified as M. neapolitanus Tenore ex Gussone or M. gracilis de Candolle; these are correctly identified as M. neapolitanus, according to the key written by G. A. Stevenson (1969). However, F. Sales and I. C. Hedge (1993) concluded that the name M. neapolitanus Tenore is confused, applied in the past to M. sulcatus Desfontaines and incorrectly applied by most authors to M. spicatus (Smith) Breistroffer. Regardless of the correct name, the species is not naturalized in the flora area.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Melilotus indicus occasionally has been grown as a forage crop in the southern United States; it is generally considered to be an undesirable weed.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Corollas white. | → 2 |
2. Flowers 3.5–5(–6) mm; pedicels 1–1.5(–2) mm; widespread, including Manitoba and Saskatchewan. | M. albus |
2. Flowers 3–3.5 mm; pedicels 2–4 mm; Manitoba, Saskatchewan. | M. wolgicus |
1. Corollas yellow. | → 3 |
3. Stipule margins dentate (mostly at base); legumes concentrically striated-veined. | M. sulcatus |
3. Stipule margins entire or subentire; legumes reticulate-veined, transversely rugose, or sigmoid-veined. | → 4 |
4. Flowers 1.5–3 mm. | M. indicus |
4. Flowers 4–7 mm. | → 5 |
5. Ovaries and young fruits appressed-pubescent. | M. altissimus |
5. Ovaries and young fruits glabrous. | M. officinalis |
- Local floras:
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
Go Botany, 
LA Plants, 
MI Flora, 
MN Wildflowers, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
