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FOC | Family List | FOC Vol. 10 | Fabaceae

136. Lotus Linnaeus, Sp. Pl. 2: 773. 1753.

百脉根属 bai mai gen shu

Bonjeanea Reichenbach; Dorycnium Miller; Miediega Bubani; Mullaghera Bubani; Scandalida Adanson; Tetragonolobus Scopoli.

Herbs, annual or perennial, subshrubs, or rarely shrubs. Leaves pinnate or palmate, usually sessile, 3-9-foliolate; stipules absent, or reduced to small dark glands; leaflets sessile or on very short petiolules, most species with 5 leaflets, 3 crowded at apex of leaf rachis, 2 at base; basal pair similar to apical ones or often differing in shape and stipulelike. Inflorescence an axillary, pedunculate, 1- to many-flowered umbel; peduncle with a sterile bract usually represented by a conspicuous leaf with 1-3(-5) leaflets; flower-sub­tending bracts reduced to small dark glands (rarely with a herbaceous blade) or absent; bracteoles usually absent, when rarely present then glandular. Calyx campanulate or trumpet-shaped; teeth 5, subequal or distal longer, sometimes connate into 2 lips. Corolla yel­low (often turning green in herbarium), pink, violet, brown, or white. Vexillary stamen free. Ovules numerous or several; style entire [or with a small toothlike appendage]; stigma terminal. Legume linear to ovoid, straight or incurved, terete or flattened, longitu­dinally dehiscent [indehiscent in 1 species outside China]. Seeds subglobose or lenticular, smooth, rarely verrucose.

About 125 species: temperate and subtropical Africa, Asia, N Atlantic islands, Australia, Europe, W Pacific islands; introduced in the Americas, New Zealand, and some other islands; eight species (one to three introduced) in China.

Sectional subdivisions are given after Kramina and Sokoloff (Byull. Moskovsk. Obshch. Isp. Prir., Otd. Biol. 108(5): 59-63. 2003) and Sokoloff (Byull. Moskovsk. Obshch. Isp. Prir., Otd. Biol. 108(3): 35-48. 2003); these are based on morphology and chromosome numbers. Molecular phylo­genetic data (Degtjareva et al., Canad. J. Bot. 84: 813-830. 2006; and Wulfenia 15: 35-49. 2008) are not always consistent with this classification (e.g., Lotus sect. Heinekenia is paraphyletic), but further research is needed to see if putatively monophyletic groups can be morphologically characterized.

Species nos. 4-7 represent the Lotus corniculatus complex, a polyploid complex including both diploid and tetraploid taxa, which are not clearly distinguishable by morphological characters. Introduced in North and South America, Australia, and New Zealand, the taxa are native to E and N Africa, Asia, and Europe.

Lotus pedunculatus Cavanilles (Icon. Descr. 2: 52. 1793; L. uliginosus Schkuhr) is a widespread species of swamps, wet meadows, and other wetlands native to N Africa, SW Asia, and Europe, and introduced in S Africa, Australia, North and South America, and the Pacific islands. In view of this broad non-native distribution, it may also be introduced in China, although no confirmed records are known to the present authors. A short de­scription is provided here. Herbs, perennial, 30-100 cm, glabrescent or sparsely pilose, with underground off-shoots. Stem erect or ascending, sub­glabrous to villous, hollow. Leaflets obovate, 8-25 × 3-15 mm, often glaucous abaxially, with prominent midrib. Heads (1-)6-12(-18)-flowered; pe­duncle long. Calyx teeth ca. as long as tube, spreading in bud, pilose. Corolla yellow, 10-18 mm. Legume 15-35 × 1.8-2.5 mm. Seeds olive or yel­lowish to light brown, usually unspotted, small, ovoid, 1-1.2 mm.

1 Basal leaflets of 5-foliolate sessile leaves adnate to leaf rachis; legume longitudinally 4-winged; flowers 18-28 mm; corolla deep red, purple, or brown when dry; plants annual; cultivated (L. sect. Tetragonolobus (Scopoli) Bentham & J. D. Hooker).   8 L. tetragonolobus
+ Leaflets never adnate to leaf rachis; legume wingless; corolla yellow, red, or white; plants perennial or annual   (2)
2 (1) Style smooth (except for inconspicuous papillae surrounding stigma); calyx trumpet-shaped; claw of standard less than half as long as standard; keel somewhat curved; all leaflets similar in shape (L. sect. Bonjeanea (Reichenbach) D. D. Sokoloff).   1 L. strictus
+ Style papillose along length (use magnification); calyx campanulate; claw of standard longer than above; keel bent at a 90° angle; basal 2 leaflets different in shape to distal 3   (3)
3 (2) Wings and standard white (occasionally pale pink or tinged with violet), keel white with reddish or pink tip; all leaflets oblanceolate or obovate, basal leaflets sometimes smaller than apical ones, but of a similar shape, with maximum width at distal or central part of a leaflet (L. sect. Heinekenia Webb & Berthelot).   2 L. taitungensis
+ Corolla yellow (then often greenish in herbarium), sometimes reddish or red; basal 2 leaflets differing in shape from apical 3 leaflets and typically having maximum width closer to leaflet base (L. sect. Lotus)   (4)
4 (4) Perennials with underground off-shoots, stem hollow.  

L. pedunculatus (see note above)

+ Annuals or perennials with a taproot, without underground off-shoots, sometimes with short rhizomes   (5)
5 (4) Stems and peduncles and often all parts of a plant with long (1-2.5 mm) spreading hairs; style 2.5-3(-3.5) mm; annual or biennial herbs (rarely short-lived perennials).   3 L. angustissimus
+ Plants without long spreading hairs; style more than 3 mm; perennial herbs (sometimes annuals or biennials) (L. corniculatus complex)   (6)
6 (5) Leaflets of cauline leaves obovate to obovate-lanceolate, leaflet index (i.e., length to width ratio) ≤ 3.5; calyx teeth longer than tube or equaling it   (7)
+ Leaflets of cauline leaves oblanceolate to linear, leaflet index ≥ 3.5; calyx teeth shorter than tube or ± equaling it   (8)
7 (6) Flowers (9-)10-15(-18) mm; corolla yellow; style 4-6 mm; narrow part of 2 upper calyx teeth less than half their length.   4 L. corniculatus
+ Flowers 8-10 mm; corolla yellow, becoming red or purple after pollination; style 3-4 mm; narrow part of 2 upper calyx teeth more than half their length.   5 L. krylovii
8 (6) Corolla yellow; calyx teeth shorter than tube; terminal leaflet 1.5-3 × as long as leaf rachis; flower 8-10.5(-11) mm; style 4-5.5 mm.   6 L. tenuis
+ Corolla yellow, usually with reddish or purple parts; calyx teeth ± equaling tube; terminal leaflet (3-)4-7 × as long as leaf rachis; flower 6-8 mm; style 3-4 mm.   7 L. schoelleri

Lower Taxa


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