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常见科植物种子特征综述ByAllenZhang禾本科Ingrass,therearetwobasickindsofspikelet,oneislateralcompression,hasextendedrachilla,canbeseeninthegrassesinsubfamilyFestucoideae;Theotherkindofspikeletisdorsalcompression,hasnoextendedrachilla,canbefoundinthePanicoideae.禾本科植物有两种基本的小穗结构，一种两侧压扁，有延伸的小穗轴，常见于早熟禾亚科的禾草上。而另一种小穗则是背腹压扁的，小穗轴不延伸到顶生小花后方，出现在黍亚科的禾草上。Theindeterminatespikelet无限小穗，两侧压扁,小穗轴延伸.Thedeterminatespikelet有限小穗，背腹压扁,小穗轴不延伸.颖果不育外稃不育内稃芒小花轴，小穗轴；通常会保留在小花上小花花梗外侧颖片外稃，常有芒内稃Theindeterminatespikelet,theseedunitoftenisfloret.无限小穗，种子单位常为小花。Thedeterminatespikelet,theseedunitoftenisspikelet.有限小穗，种子单位常为小穗。Festuca羊茅属Echinochloa稗属第一颖片第二颖片禾本科植物的小花Anther花药浆片胚珠外稃内稃Stigma柱头小穗轴Sinus,thespacebetweenthemarginsofalemmaatthebaseofafloretontheventralside.窦，小花基部腹侧的外稃边缘所构成的空间。Callus,asmooththickenedlayeratthebaseofafloret基盘，小花基部光滑的增厚细胞层。Thetextureoflemmaandpaleavaryindifferentspecies.Theymaybethinandtranslucent,hardandplano-convex,orrigidandbrittle.内外稃的质地在不同的物种中差异明显。它们可能是薄而透明的，坚硬而平凸型的或坚硬而易碎的。Theembryoonthedorsalside在颖果背侧的胚Thehilumontheventralside在颖果腹侧的种脐Ingrass,thetrueseedisfusedwithovarywallandthehilumisnotatruehilum.Thistypeoffruitiscalledacaryopsis.禾本科植物的真种子与子房壁愈合在一起，它的种脐不是真正的种脐。这种类型的果实称之为颖果。Theembryoliesontheoutsideofendospermandplainlyvisiblenearthebaseofcaryopsisonthedorsalside.Thisisthecharacteristicofgrass.胚位于胚乳的外侧，且容易在颖果背侧基部观察到。这是禾本科植物种子的典型特征。Setariaitalica小米，谷子Triticumaestivum小麦Sometimesthefloretswillhaveappendant,suchasawn,sterilelemmaandsoon.有时，小花上会带有附属物,如芒，不育外稃等。Festucarubra紫羊茅Alopecuruspratensis大看麦娘Avenafatua野燕麦Awn,attachondifferentpositionoflemma.alsocanbefoundonglumesandpalea.Itisstraight,twisted,orbent.芒，着生在外稃的不同部位，也可在颖片和内稃上发现，直、扭转或弯曲。Ariastida，hasthreeawnsonlemma.三芒草属，外稃上有三个芒。ThegeniculateawnofAvenafatua野燕麦膝状弯曲的芒Phalariscanariensis金丝雀虉草Oryzasativa栽培稻Anthoxanthumodoratum黄花茅Sterilelemma,atthebaseoffloret,sometimesenclosethefloret.不育外稃，着生在小花基部，有时包裹小花。Ehrhartaerecta,panicveldtgrassHierochloeodorata,茅香Fortheseedunitthatisspikelet,theattachedglumeshavemanyformsandsometimeswillhaveotherappendant,likeinvolucreandsegmentofrachis.对于种子单位可为小穗的禾本科植物，其附着的颖片有许多的形态，有时还会有其它的附着物，如总苞和花轴段。Hordeumbulbosum球茎大麦Beckmanniasyzigachne菵草Alopecurusmyosuroides大穗看麦娘Aegilopscylindrica山羊草Sorghumhalepense假高粱Setariaviridis狗尾草Boutelouadactyloides野牛草Eremochloaophiuroides假俭草Hackelochloagranularis球穗草DifferentGlumes,someofthemenclosethespikelets.不同形态的颖片，其中一些颖片完全包裹内部的小穗。Hilariamutica,tobosagrassHolcusmollis德国绒毛草Lepturusrepens细穗草Phalarisaquatica球茎虉草Ischaemumindicum细毛鸭嘴草Phleumpratense梯牧草Polypogonmonspeliensis长芒棒头草Tragusracemosus锋芒草Zoysiatenuifolia细叶结缕草Tripsacumdactyloides鸭茅状磨擦禾DifferentGlumes,theymaybeleathery,stiff,tissue-like,papery,awned,barbedonthekeel,wingedonthetoporonthekeel.不同形态的颖片，它们可能是革质的，坚硬的，膜质的，纸状的，有芒的，脉脊上有钩刺的，在顶部或脉脊上有翅的。Involucre,bornatthebaseofspikeletorinflorescence,maylikebristle(e.g.PennisetumandSetaria),bur(e.g.Cenchrus),spathe(e.g.CymbopogonandThemeda)orbegloboseandsoon.总苞，生于小穗或花序基部，可能为刚毛状（如狼尾草属和狗尾草属），刺苞状（蒺藜草属）,佛焰苞状（香茅属和菅属）或者为球形（薏苡属）等。Pennisetumflaccidum白草Setariasetosa,westIndianbristlegrassCenchruslongispinus长刺蒺藜草Coixlacryma-jobi薏苡Anthephorahermaphrodita,oldfieldgrassThespatheandinflorescenceofCymbopogonnardus,亚香茅的佛焰状总苞及花序Segmentofrachis,usuallycanbeseenintheAndropogoneae.Somesegmentofrachisincertainspecies(e.g.inCoelorachis,Hemarthira,Rottboellia,Tripsacum,AegilopsandLepturus,)canrollandfloatthefruittotheirnewhome.花轴段，通常可在高粱族（蜀黍族）禾草种子单位上发现。一些物种的花轴段能够让果实滚动或漂浮到新的地方（如空轴茅属，Limpograss属，筒轴茅属，摩擦禾属，山羊草属及细穗草属）。Sorghumhalepense,假高粱Segmentofrachis花轴段Pedicelofpedicellatespikelet有柄小穗的花梗Aegilopscylindrica山羊草Tripsacumdactyloides鸭茅状磨擦禾Coelorachistuberculosa,bumpyjointtailgrassHemarthiraaltissima,LimpograssRottboelliacochinchinensis筒轴茅Ifyouwanttoseemorestructuresaboutgrass,goto更多的禾本科植物结构图可登陆莎草科TriangularStem茎三角形带有许多小穗的花序总苞片苞片，鳞片辐射枝ThespikeletofCyperaceaecontains2-moreflowerswithbracts.Thespikeletsgrowsinglyortogetherthatcanbespicateorcapitate.Sometimesthespikeletonlyhas1flower.Thereare2commonflowers(orspikelet)arrangementmodes.莎草科的小穗由2-多数带鳞片的花组成，小穗单生，簇生或排列成穗状或头状，有时退化仅具1花。小花或小穗有2种基本的排列方式。Bractsgrowinsprialarrangement鳞片以螺旋状排列Bractsgrowin2linesarrangement鳞片以左右2纵行排列Caricoideae:oftenbeunisexualflower(someofKobresiaarenot)andsomeflowerhasaxisrudiment.Thefemaleflowerhasprophyllwhichoftencompletelyclosedexceptatapex(exceptfortheKobresia).薹草亚科：常为单性花(嵩草属部分不是)且部分有退化的小穗轴；雌花有先出叶，大多数先出叶边缘完全（除了顶端）合生成果囊（嵩草属先出叶边缘分离）。果囊（先出叶）鳞片退化轴雌蕊小穗轴先出叶退化轴鳞片退化轴鳞片Cyperaceaecanbedividedintotwosubfamily,theCaricoideaeandScirpoideae.莎草科植物可分成两个亚科，分别是薹草亚科和藨草亚科。雄蕊Scirpoideae:Theflowerhasnoprophyll.莎草亚科：花无先出叶。莎草亚科的两性花，从上到下分别是柱头，花药，胚珠，鳞片（苞片）。莎草科小花的花被片常退化成刚毛状，丝毛状、鳞片状或缺如。花柱1，柱头2或3。果实为小坚果。下位刚毛禾本科、莎草科及灯心草科的形态特征类似。禾本科（上）小花具内外稃；莎草科（左）小花具鳞片，灯心草科（右）小花具6枚花被片且果实为蒴果。SeedcharacteristicofCyperaceae莎草科种子特征TheseedofCyperaceaeoftenbenutletwhichcouldbetriangular,lenticular,orglobular.莎草科植物的种子常为小坚果，三棱状，双凸状或球状。Cyperusfuscus密穗莎草Eleocharisovata卵穗荸荠Isolepissetacea细菀Rhynchosporaalba白鳞刺子莞Scleria珍珠茅属Scirpusplaniculmis扁秆藨草薹草亚科重要属-苔草属花单性，雌雄同株，少数异株。小穗由多个支小穗组成。每个支小穗（相当于退化成只含1花的小穗）内有鳞片，部分有退化轴，雌花基部有先出叶形成果囊。小穗