AcrocomiaFrom Wikipedia, the free encyclopediaAcrocomia

Scientific classification

Kingdom:Plantae

(unranked):Angiosperms

(unranked):Monocots

(unranked):Commelinids

Order:Arecales

Family:Arecaceae

Subfamily:Arecoideae

Tribe:Cocoseae

Genus:AcrocomiaMart.

Synonyms[1]

GastrococosMorales AcanthococosBarb.Rodr.

Acrocomiais a genus ofpalmswhich is native to theNeotropics, ranging fromMexicoin the north, throughCentral Americaand theCaribbean, and throughSouth Americasouth toArgentina.[1][2]Description[edit]Acrocomiais a genus ofspiny,pinnate-leaved palms which range from large trees to small palms with short, subterranean stems.[3]The species bears branchedinflorescenceswhich are located among the leaves. Theunisexual flowers; female flowers are born near the base of the inflorescence, while male flowers are borne towards the tips. Fruit are large, single-seeded, and vary in colour from yellow, to orange, to brown.[3]Species[edit]1. Acrocomia aculeata(Jacq.)Lodd.ex R.Keith- Mexico, Central America, West Indies, northern South America2. Acrocomia crispa(Kunth) C. Baker ex.Becc.- Cuba3. Acrocomia emensis(Toledo) Lorenzi- Brazil4. Acrocomia glaucescensLorenzi- Brazil5. Acrocomia hassleri(Barb.Rodr.)W.J.Hahn- Mato Grosso do Sul, Paraguay6. Acrocomia intumescensDrude- Brazil7. Acrocomia mediaO.F.Cook- Puerto Rico, Virgin Islands8. Acrocomia totaiMart.- Bolivia, Paraguay, northern Argentina, southern BrazilReferences[edit]Wikimedia Commons has media related toAcrocomia.

1. ^Jump up to:abKew World Checklist of Selected Plant Families2. Jump up^Govaerts, R. & Dransfield, J. (2005). World Checklist of Palms: 1-223. The Board of Trustees of the Royal Botanic Gardens, Kew.3. ^Jump up to:abHenderson, Andrew;Gloria Galeano;Rodrigo Bernal(1995).Field Guide to the Palms of the Americas. Princeton, New Jersey: Princeton University Press. pp.4550.ISBN0-691-08537-4.ThisCocoeaearticle is astub. You can help Wikipedia byexpanding it.

Thorns, spines, and pricklesFrom Wikipedia, the free encyclopedia(Redirected fromSpine (botany))This articlemay requirecleanupto meet Wikipedia'squality standards.Nocleanup reasonhas been specified. Please helpimprove this articleif you can.(February 2011)

Inplant morphology,thorns, spines, prickles, and in generalspinose structures(asspinose teeth,spinose apical process) are all hard structures with sharp, stiff ends, generally with the same function of physically deterring animals from eating the plant material.In common language the terms are used more or less interchangeably, but in botanical terms, thorns are derived fromshoots(so they can be branched or not, they can have leaves or not, and they arise from a bud),[1][2][3][4]spines are derived fromleaves(the entire leaf or some part of the leaf that has vascular bundles inside, like thepetioleor astipule),[1][2][3][4]and prickles are derived from theepidermis(so they can be found anywhere on the plant, and don't have vascular bundles inside so they can be removed more easily and cleanly than thorns and spines[4]).[1][2][3]Leaf margins also may have teeth, and if those teeth are sharp, they are called spinose teeth on a spinoseleaf margin[1][2](some authors consider them a kind of spine[2]). On a leaf apex, if there is an apical process (generally an extension of the midvein), and if it is specially sharp, stiff, and spinelike, it can be called spinose or pungent apical process[1](again, some authors call them a kind of spine[2]). When epidermis is covered with very long, stifftrichomes(more correctly calledbristlesin this case,[1]for some authors a kind of prickle[2]) is calledhispid vestiture,[1][2][3]if is covered with stinging trichomes it can be calledurent vestiture.[1]Contents[hide] 1Function 2Definitions and technical distinctions 2.1Types of spines 3Evolution 4Morphological variation 5In human culture 6See also 7References 8External linksFunction[edit]The predominant function of thorns, spines and prickles is deterringherbivoryin a mechanical form.Not all functions of spines orglochidsare limited to defence from physical attacks by herbivores and other animals. In some cases, spines have been shown to shade or insulate the plants that grow them: for example, the saguaro cactus spines shade the apical meristem in summer and in members of theOpuntioideaeglochids insulating the apical meristem in winter.Agrawalet al.(2000) found that spines seem to have little effect on pollinators, which the plants need in order to reproduce.[5]Definitions and technical distinctions[edit]Pointing or spinose processes can broadly be divided by the presence of vascular tissue:thorns and spinesare derived from shoots and leaves respectively, and have vascular bundles inside, whereasprickles(like rose prickles) don't have vascular bundles inside, so they can be removed more easily. (A) Thorn or spine(B) Prickle A spinose tooth in a leaf margin. A spinose apical process. Thornsare modified branches orstems. They may be simple or branched. Thorns are derived from shoots, they can be branched and they can have leaves. They arise from a bud. Smooth, featurelessCitrusthorn. Gymnosporia buxifoliathorn, its leaves, nodes, and emergence from an axillary bud demonstrating its nature as a branch. Carissa bispinosashowing characteristic branched thorns. Spinesare modifiedleaves,stipules, or parts of leaves, such as extensions of leaf veins. The spines ofFouquieria splendens(Ocotillo) develop from the leafpetioles. Stipule spines onAcacia xanthophloea. Cacti areoles. Shoot (yellow), spines (green) and bristles (brown). Areoles and spines of the tree likePereskia grandifolia. Pricklesare comparable to hairs but can be quite coarse (for example, rose prickles), i.e. they are extensions of thecortexandepidermis.[6][7] Raised prickles on the stem ofCaesalpinia decapetala. Roseprickles. Prickles on the leaves ofSolanum viarum.Spinescentis a term describing plants that bear any sharp structures that deters herbivory. It also can refer to the state of tending to be or become spiny in some sense or degree, as in: "...the division of the African acacias on the basis of spinescent stipules versus non-spinescent stipules..."[8]Some authors prefer not to distinguish spines from thorns because, like thorns, and unlike prickles, they commonly containvascular tissue.[9]Technically speaking, many plants commonly thought of as having thorns or spines actually have prickles.Roses, for instance, have prickles.[9]Other structures that look alike are spinose teeth, spinose apical process, stiff trichomes and stinging trichomes. Spinose leaf margin inIlex aquifolium. Spinose apical process inSansevieria. Stiff sharped trichomes inGalium aparine. Stinging trichome inUrtica dioica.Types of spines[edit]Cacti can have a particular kind of spine (modified leaf) very small and deciduous, with numerous retrorse barbs along its length, this particular spine is calledglochidiumorglochid(plural glochidia or glochids), as found in areoles ofOpuntia.[1]Spines can bepetiolar spinesas those ofFoquieria,leaflet spinesas inPhoenix,stipular spinesas inEuphorbia, all those are examples of spines developing from a part of a leaf containing the petiole, midrib, or a secondary vein.[1]Evolution[edit]It has been proposed that thorny structures may first have evolved as adefense mechanismin plants growing in sandy environments that provided inadequate resources for fast regeneration of damage.[10][11]However, the suggestion was unsupported by any argument to discount the likelihood that spiny defences might have been developed as a means of defence in resource-rich environments where herbivory might have been more intense than in the hypothesized sandy environments.[citation needed]Morphological variation[edit]Spinose structures occur in a wide variety of ecologies, and their morphology also varies greatly. They occur as: sharpened branches (e.g. inCarissa,Citrus,Crataegus), spiky inflorescences (e.g. inTylecodon reticulatus),[12] a tiny point at the tip of the leaf (mucronate leaves) (e.g. inSansevieria),[13] leaves fully converted to spines (e.g. inOpuntia),[14] stipules converted to spines (e.g. in manyAcacia), prickles on stems (e.g. ofRosa,ErythrinaandCeiba speciosa), urticating (i.e. stinging) hairs, bristles, and finely barbed spines calledglochids.Some thorns are hollow and act asmyrmecodomatia, others (e.g. inCrataegus monogyna) bear leaves. Thorns of some species are branched (e.g. inCrataegus crus-galli,Carissa macrocarpa).In human culture[edit]Primitive humans are known to have used thorns as tools. Human history records a variety of cultural references to sharp-pointed plant defensive mechanisms.TheBook of Genesisrecounts the creation of thorns as one of the punishments for the sin of Adam and Eve, stating, "Thorns also and thistles shall [the ground] bring forth to thee; and thou shalt eat the herb of the field." Genesis, 3:18. One of the most enduring cultural images is theCrown of Thornsdescribed in theBibleas having been placed on the head ofJesusbeforehis crucifixion. It is mentioned in theGospelsofMatthew(27:29),Mark(15:17), andJohn(19:2, 5) and is often alluded to by the early Christian Fathers, such asClement of Alexandria,Origen, and others. For example,John the Evangeliststates that "the soldiers plaited a crown of thorns, and put it on his head". (KJV, ch. 19). The biblical account does not specify what kind of thorns were involved, and leaves no clues from which to determine whether these were biologically classifiable as thorns, spines, or prickles.An early popular myth involving a thorn is that ofAndrocles, a fugitive slave in ancient Greece who was said to have befriended a lion by pulling a thorn from the lion's paw.[15]The status of theScottish Thistleas the national emblem of Scotland is founded on the story (recountedhere) that an invading Norse army attempting a night attack was betrayed when they encountered a thistle in the dark.Plants bearing thorns, spines, or prickles are often used as a defense againstburglary, being strategically planted below windows or around the entire perimeter of a property.[16]They also have been used to protect crops and livestock against marauding animals. Examples includehawthornhedges in Europe,Agavesin the Americas and in other countries where they have been introduced,Osage Orangein the prairie states of the US, andSansevieriain Africa.[17]In modern times, the study ofacanthochronologyhas used theoxygenisotopecomposition of spines fromsaguarocactus to determine historical changes in local rainfall and reconstructclimateand plantecophysiologyover the plant's lifetime.See also[edit] Areole GlochidReferences[edit]General references: Simpson, M. G. 2010. "Plant Morphology". In:Plant Systematics, 2nd. edition. Elsevier Academic Press. Chapter 9. Judd, Campbell, Kellogg, Stevens, Donoghue. 2007. "Structural and Biochemical Characters". In:Plant Systematics, a phylogenetic approach, third edition. Chapter 4.1. ^Jump up to:abcdefghijSimpson, M. G. 2010. "Plant Morphology". In:Plant Systematics, 2nd. edition. Elsevier Academic Press. Chapter 9.2. ^Jump up to:abcdefghJudd, Campbell, Kellogg, Stevens, Donoghue. 2007. "Structural and Biochemical Characters". In:Plant Systematics, a phylogenetic approach, third edition. Chapter 4.3. ^Jump up to:abcdTurner et al. 2005,Sonoran Desert Plants, an Ecological Atlas.University of Arizona Press.4. ^Jump up to:abcVan Wyk, Van Wyk. 2007.How to identify trees in South Africa.Struik.5. Jump up^Agrawal, A, A., Rudgers, A, J., Botsford, W, L., Cutler, S., Gorin, B, J., Lundquist, C, J., Spitzer, W, B., & Swann, L, A. (2000). Benefits and Constraints on Plant Defense against Herbivores: Spines Influence the Legitimate and Illegitimate Flower Visitors of Yellow Star Thistle,Centaurea solstitialisL. (Asteraceae). JSTOR, 45(1), 1-5.http://www.jstor.org/stable/3672545. retrieved 2012-03-206. Jump up^Van Wyk, Braam (2007).How to Identify Trees in Southern Africa(illustrated ed.). Struik. p.184.ISBN9781770072404.7. Jump up^Sengbusch, Peter (2003-07-31)."Cross-Section Through the Prickle of a Rose". Retrieved2009-04-27.8. Jump up^Ross, J. H. "A conspectus of the African Acacia species." Series: Memoirs of the Botanical Survey of South Africa, No. 44 Botanical Research Institute, Dept. of Agricultural Technical Services, Pretoria, 19799. ^Jump up to:abBell, A.D. 1997.Plant form: an illustrated guide to flowering plant morphology. Oxford University Press, Oxford, U.K.preview in google books10. Jump up^Steve Brill, Evelyn Dean,Identifying and Harvesting Edible and Medicinal Plants(1994), p. 17.11. Jump up^August Weismann, John Arthur Thomson, Margaret R. Thomson,The Evolution Theory(1904), p. 124.12. Jump up^Bihrmann.com13. Jump up^Dyer, R. Allen, The Genera of Southern African Flowering Plants, Vol 2.ISBN 0-621-02863-0, 197614. Jump up^Anderson, Edward F., The Cactus Family, Pub: Timber Press 2001ISBN 978-0-88192-498-515. Jump up^Carrington, Norman T., Shaw, George Bernard. Androcles and the Lion: Brodies Notes. Publisher: Macmillan, 1976,ISBN 978-0-330-50050-016. Jump up^Marcus Felson,Crime and Nature(2006), p. 288.17. Jump up^Hunter, J. A., "Hunter" Publisher: Buccaneer Books, 1993,ISBN 978-1-56849-109-7