決明

決明學名Senna tora (Linn.) Roxb.、Cassia tora Linn.、Cassia gallinaria Collad.、Cassia numilis Collad.、Cassia borneensis Miq.、Cassia boreensis Miq.、Cassia tora var. borneensis (Miq.) Miq.，英文名Sickle Senna、Sickle Pod，豆科蘇木(雲實)亞科決明(番瀉決明、黃槐、鐵刀木)屬一年生灌木狀草本植物，又稱草決明、馬蹄決明、小決明、大號山土豆、假綠豆、決明子，原產於北美洲熱帶至亞熱帶地區，株高三十至二百公分，根大多數具根瘤菌，亞灌木植物，莖直立，粗壯，多分枝，近無毛，幼莖有明顯氣味，葉互生，偶數羽狀複葉，小葉對生，約二至四對，通常三對，小葉倒卵形、倒卵狀長橢圓形、卵狀長橢圓形，端部圓鈍，具小小突尖頭，基部漸狹、廣楔形、鈍形，偏斜，全緣葉，葉長四至八公分，小葉長二至六公分、寬十至二十五公釐，膜質，葉表面綠色，被稀疏柔毛，葉背面被柔毛，第一、二對小葉間有腺體，羽狀脈，具葉枕，托葉線形，被柔毛，早落性，葉軸上每對小葉間有棒狀腺體一枚，葉柄長，小葉長一、二公釐或近無柄，無腺體，兩性花，總狀花序，腋生，常二枚成對著生於葉腋上，總花梗長六至十公釐，花梗長十至十五公釐，絲狀，苞片線形，花萼筒狀，合生，先端五裂，覆瓦狀排列，裂片卵形、卵狀長圓形、長卵形，長約八公釐，膜質，萼片稍不等大，外面被柔毛，花冠蝶形，花黃、淡黃色，花瓣五枚，長十二至十五公釐，寬五至七公釐，下面二枚略長，具瓣柄，覆瓦狀排列，離生，雄蕊十枚，可育雄蕊七枚，等長或不等長，離生，花絲短於花藥，花藥四方形，頂孔開裂，長約四公釐，退化雄蕊三枚，雌蕊心皮一枚，柱頭頭狀，子房無柄，被白色柔毛，子房上位，子房一室，邊緣胎座，莢果，圓柱形，呈鐮刀狀，長約十至十五公分，寬二至五公釐，膜質，纖細，有時扁平或呈四角狀，兩端漸尖，不開裂或二瓣裂，種子約二十至五十枚，菱形，青果灰綠色，光亮，有光澤，熟果褐色。

山扁豆(Chamaecrista)屬、阿勃勒(Cassia)屬原歸類於決明(Senna)屬之下，中文通稱「決明屬」，目前三屬已拆分，三者是蘇木亞科決明族。

「決明屬」種檢索表：
A.葉柄及小葉軸皆不具腺體。-----★鐵刀木
A.葉柄及小葉軸其一具腺體。
▁B.葉柄具腺體。
▁▁C.植株密被粗毛。-----★毛決明
▁▁C.植株近無毛。
▁▁▁D.莢果圓柱形。-----★大花黃槐
▁▁▁D.莢果扁平。-----★望江南
▁B.小葉軸具腺體。
▁▁C.小葉4-6對。-----★黃槐
▁▁C.小葉3對。-----★決明

常見決明(Senna)屬的品種有：
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Senna acanthoclada
Senna acclinis
Senna aciphylla
Senna acillaris
Senna aculeata
Senna acunae
Senna acuparata
Senna acutifolia(亞歷山大決明)
Senna acuruensis
Senna acutisepala
Senna affinis
Senna agnes(神黃豆)
Senna alata(翅果鐵刀木、翅莢決明、翼柄決明)
Senna alexandrina(旃那、番瀉草)
Senna andrieuxii
Senna angulata
Senna angustisiliqua
Senna ankaranensis
Senna anthoxantha
Senna aphylla
Senna apiculata
Senna appendiculata
Senna apsidoneura
Senna araucarietorum
Senna argentea
Senna arida
Senna aristeguietae
Senna armata
Senna arnottiana
Senna artemisioides
Senna atomaria
Senna aurantia
Senna auriculata(耳葉決明、麻榻勒茶)
Senna aversiflora
Senna aymara
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Senna baccarinii
Senna bacillaris
Senna bakeriana(花旗木、桃紅陣雨樹、粉紅陣雨樹、泰國櫻花、金杯黃槐)
Senna barclayana
Senna barnebyana
Senna barronfieldii
Senna bauhinioides
Senna benitoensis
Senna bicapsularis(雙莢決明)
Senna bicapsularis 'California Gold'
Senna bicapsularis 'Worley's Butter Cream'
Senna biglandularis
Senna birostris
Senna bosseri
Senna bracteosa
Senna brongniartii
Senna burkartiana
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Senna cajamarcae
Senna calycioides
Senna cana
Senna candolleana
Senna cardiosperma
Senna catingae
Senna caudata
Senna cearensis
Senna centranthera
Senna cernua
Senna chapmanii
Senna charlesiana
Senna chloroclada
Senna chrysocarpa
Senna cladophylla
Senna clavigera
Senna cobanensis
Senna coimbrae
Senna collicola
Senna confinis
Senna corifolia
Senna cornigera
Senna coronilloides
Senna corymbosa(繖房決明)
Senna costata
Senna covesii
Senna crassiramea
Senna crotalarioides
Senna cruckshanksii
Senna cuatrecasasii
Senna cumingii
Senna curvistyla
Senna cushina
Senna cuthbertsonii
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Senna dardanoi
Senna dariensis
Senna davidsonii
Senna demissa
Senna didymobotrya(長穗決明、複總望江南)
Senna didymobotrya 'Popcorn Senna'
Senna divaricata
Senna domingensis
Senna durangensis
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Senna ellisiae
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Senna ferraria
Senna flexuosa
Senna foetidissima
Senna formosa
Senna fruticosa(大葉決明、四葉黃槐)
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Senna galeottiana
Senna gardneri
Senna garrettiana
Senna gaudichaudii
Senna glauca(粉葉決明)
Senna georgica
Senna glanduligera
Senna glaucifolia
Senna glutinosa
Senna goniodes
Senna gossweileri
Senna guatemalensis
Senna gundlachii
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Senna hamersleyensis
Senna harleyi
Senna haughtii
Senna hayesiana
Senna hebecarpa
Senna heptanthera
Senna herzogii
Senna hilariana
Senna hirsuta(毛決明、毛莢決明)
Senna holosericea
Senna holwayana
Senna hookeriana
Senna huancabambae
Senna huidobriana
Senna huilana
Senna humifusa
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Senna incarnata
Senna insularis
Senna intermedia
Senna italica
Senna itatiaiae
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Senna koelziana
Senna kurtzii
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Senna lactea
Senna lasseigniana
Senna latifolia
Senna leandrii
Senna leiophylla
Senna leptoclada
Senna leschenaultiana(大葉山扁豆、短葉決明)
Senna ligustrina
Senna lindheimeriana
Senna longiglandulosa
Senna longiracemosa
Senna loretensis
Senna lourteigiana
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Senna macranthera
Senna macrophylla
Senna magnifolia
Senna malaspinae
Senna mandonii
Senna manicula
Senna marilandica
Senna martiana
Senna mensicola
Senna meridionalis
Senna mexicana
Senna mimosoides(山扁豆、含羞草決明)
Senna mollissima
Senna monilifera
Senna monozyx
Senna montana
Senna morongii
Senna mucronifera
Senna multiglandulosa
Senna multijuga(密葉決明、小葉黃槐)
Senna mutisiana
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Senna nana
Senna neglecta
Senna nicaraguensis
Senna nitida
Senna nodosa(節果決明)
Senna nomame(豆茶決明)
Senna notabilis
Senna nudicaulis
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Senna obliqua
Senna oblongifolia
Senna obtusifolia(草決明、決明)
Senna occidentalis(望江南)
Senna odorata
Senna oligoclada
Senna orcuttii
Senna organensis
Senna oxyphylla
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Senna pachyrrhiza
Senna pallida
Senna papillosa
Senna paposana
Senna paradictyon
Senna paraensis
Senna pendula
Senna pentagonia
Senna peralteana
Senna perrieri
Senna petersiana
Senna phlebadenia
Senna phyllodinea
Senna pilifera
Senna pilocarina
Senna pilosio
Senna pinheiroi
Senna pistaciifolia
Senna planitiicola
Senna pleurocarpa
Senna pneumatica
Senna podocarpa(羅漢決明)
Senna polyantha
Senna polyphylla(沙漠黃槐)
Senna praeterita
Senna procumbens
Senna pumilio
Senna punoensis
Senna pumila(柄腺山扁豆)
Senna purpurea
Senna purpusii
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Senna quinquangulata
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Senna racemosa
Senna reniformis
Senna reticulata
Senna rigidicaulis
Senna ripleyana
Senna rizzinii
Senna robiniifolia
Senna roemeriana
Senna rostrata
Senna rugosa
Senna ruiziana
Senna rupununiensis
Senna ruspolii
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Senna saeri
Senna sandwithiana
Senna santanderensis
Senna scabriuscula
Senna scandens
Senna septemtrionalis
Senna sericea
Senna siamea(鐵刀木)
Senna silvestris
Senna singueana
Senna skinneri
Senna smithiana
Senna sophera(槐葉決明)
Senna sophora
Senna sousana
Senna spectabilis(美麗決明)
Senna spinescens
Senna spiniflora
Senna spinigera
Senna splendida
Senna stenophylla
Senna stipulacea
Senna stowardii
Senna stricta
Senna suarezensis
Senna subtrijuga
Senna subulata
Senna sulfurea(黃槐、黃槐決明)
Senna surattensis(黃槐決明)
Senna symonii
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Senna talpana
Senna tapajozensis
Senna tapajozensis
Senna tenuifolia
Senna timoriensis(帝汶明)
Senna tocotana
Senna tonduzii
Senna tora(決明、小決明)
Senna trachypus
Senna trianae
Senna trolliiflora
Senna tropica
Senna truncata
Senna tuhovalyana
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Senna uncata
Senna undulata
Senna uniflora
Senna unijuga
Senna urmenetae
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Senna vargasii
Senna velutina
Senna venusta
Senna versicolor
Senna viarum
Senna viciifolia
Senna viguierella
Senna villosa
Senna viminea
Senna viminea
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Senna weddelliana
Senna williamsii
Senna wislizeni
Senna wurdackii
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Senna × floribunda(大花黃槐、光葉決明)
Senna × nealiae(彩虹阿勃勒)
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Senna 'Species'
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