Raphide

{{Short description|Plant chemical defense}} {{Use dmy dates|date=January 2024}} [[File:Raphides from variegated ivy.jpg|thumb|Raphides in ''Epipremnum'' ''Devil's ivy'' (600× magnification)]] '''Raphides''' ({{IPAc-en|ˈ|r|æ|f|ɪ|d|i|z}} {{respell|RAF|id|eez}}; singular ''raphide'' {{IPAc-en|ˈ|r|eɪ|f|aɪ|d}} {{respell|RAY|fyde}} or ''raphis'') are needle-shaped crystals of calcium oxalate monohydrate (prismatic monoclinic crystals) or calcium carbonate as aragonite (dipyramidal orthorhombic crystals), found in more than 200 families of plants. Both ends appear needle-like, but raphides tend to be blunt at one end and sharp at the other.

== Calcium oxalate in plants == [[File:raphide.jpg|thumb|left| Raphides in ''Hypoestes phyllostachya'', the polka dot plant]]

Many plants accumulate calcium oxalate crystals in response to surplus calcium, which is found throughout the natural environment. The crystals are produced in a variety of shapes. The crystal morphology depends on the taxonomic group of the plant. In one study of over 100 species, it was found that calcium oxalate accounted for 6.3% of plant dry weight.<ref>{{cite journal|doi=10.1105/tpc.11.4.751|title=Cell-Mediated Crystallization of Calcium Oxalate in Plants|journal=The Plant Cell Online|volume=11|issue=4|pages=751–761|year=1999|last1=Webb|first1=M. A.|pmid=10213791|pmc=144206}}</ref> Crystal morphology and the distribution of raphides (in roots or leaves or tubers etc.) is similar in some taxa but different in others leaving possible opportunities for plant key characteristics and systematic identification; mucilage in raphide containing cells makes light microscopy difficult, though. Little is known about the mechanisms of sequestration or indeed the reason for the accumulation of raphides but it is most likely as a defense mechanism against herbivory. It has also been suggested that in some cases raphides may help form plant skeletal structures. Raphides typically occur in parenchyma cells in aerial organs, especially the leaves, and are generally confined to the mesophyll. As the leaf area increases, so does the number of raphides, the process starting in even young leaves. The first indication that the cell will contain crystals is shown when the cells enlarge with a larger nucleus.<ref>{{cite journal|url=http://jcs.biologists.org/content/11/2/339.full.pdf|pmid=4342516|year=1972|last1=Horner|first1=H. T. Jr.|title=Raphide crystal cell development in leaves of Psychotria punctata (Rubiaceae)|journal=Journal of Cell Science|volume=11|issue=2|pages=339–55|last2=Whitmoyer|first2=R. E.|doi=10.1242/jcs.11.2.339}}</ref>

Raphides are found in specialized plant cells or crystal chambers called idioblasts.<ref name="weber">{{cite journal|doi=10.1021/ja02124a034|url=https://zenodo.org/record/1428965|title=Raphides, the Cause of the Acridity of Certain Plants|journal=Journal of the American Chemical Society|volume=13|issue=7|pages=215–217|year=1891|last1=Weber|first1=R. A.|bibcode=1891JAChS..13..215W |doi-access=free}} Also, {{doi|10.1038/scientificamerican11211891-13242csupp}}</ref> Electron micrographs have shown that raphide needle crystals are normally four sided or H-shaped (with a groove down both sides) or with a hexagonal cross section and some are barbed. Wattendorf (1976) suggested that all circular sectioned raphides, as visible in a light microscope, are probably hexagonal in cross section<ref>{{cite journal|doi=10.1007/BF00387837|pmid=24424644|title=A third type of raphide crystal in the plant kingdom: Six-sided raphides with laminated sheaths in Agave americana L|journal=Planta|volume=130|issue=3|pages=303–11|year=1976|last1=Wattendorff|first1=Joachim|bibcode=1976Plant.130..303W |s2cid=22882070}}</ref> The hexagonal crystals reported by Wattendorf in ''Agave americana'' were apparently calcium oxalate.<ref>According to [http://archive.wikiwix.com/cache/20140530000000/http://www.accessdata.fda.gov/scripts/Plantox/Detail.CFM?ID=22861 this abstract] in the FDA Poisonous Plant Database ''Agave americana'' contains calcium oxalate crystals, acrid oils, saponins, and other compounds.</ref>

Microscopy using polarized light shows bright opalescence with raphides.

Plants like ''Tradescantia pallida'' also accumulate calcium oxalate crystals in response to heavy metals stress.{{citation needed|date=November 2021}}

== Harmful effects == Raphides can produce severe toxic reactions by facilitating the passage of toxin through the herbivore's skin when the tissue containing the raphides also contains toxins. The lethal dose to mice is around 15 mg/kg.<ref>{{cite journal |pmid=18533491|year=2008|last1=Wu|first1=H|title=Study on irritation of calcium oxalate crystal in Araceae plants|journal=Zhongguo Zhong Yao Za Zhi|language=Chinese|volume=33|issue=4|pages=380–4|last2=Zhong|first2=L. Y.}}</ref> Raphides seem to be a defense mechanism against plant consuming animals,<ref>{{cite journal|pmid=10648203|jstor=3080127|year=2000|last1=Arnott|first1=H. J.|title=Twinned Raphides of Calcium Oxalate in Grape (Vitis): Implications for Crystal Stability and Function|journal=International Journal of Plant Sciences|volume=161|issue=1|pages=133–142|last2=Webb|first2=M. A.|doi=10.1086/314230|bibcode=2000IJPlS.161..133A |s2cid=3009411 }}</ref> as they are likely to tear and harm the soft tissues of the throat or esophagus of an animal chewing on the plant's leaves.<ref>{{cite web|url=http://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/taro-0| title=Animal Poison Control Center: Taro|work= ASPCA}}</ref><ref>{{cite web|url=http://www.rightdiagnosis.com/p/plant_poisoning_calcium_oxalate_crystals/intro.htm| title=Plant poisoning – Calcium oxalate crystals |work=Right Diagnosis from Healthgrades}}</ref> The venomous process is in two stages: mechanical pricking and injection of harmful protease. Typically ingestion of plants containing raphides, like those common in certain houseplants, can cause immediate numbing followed shortly by painful edema, vesicle formation and dysphagia accompanied by painful stinging and burning to the mouth and throat with symptoms occurring for up to two weeks.<ref>{{cite journal |doi=10.1081/CLT-44721 |pmid=15732442 |title=Outbreak of Food-borne Illness Associated with Plant Material Containing Raphides |journal=Clinical Toxicology |volume=43 |issue=1 |pages=17–21 |year=2005 |last1=Watson |first1=John T. |last2=Jones |first2=Roderick C. |last3=Siston |first3=Alicia M. |last4=Diaz |first4=Pamela S. |last5=Gerber |first5=Susan I. |last6=Crowe |first6=John B. |last7=Satzger |first7=R. Duane |s2cid=388923 }}</ref> Airway assessment and management are of the highest priority, as are extensive irrigation and analgesics in eye exposure.

Raphides cannot normally be destroyed by boiling; that requires an acidic environment or chemical solvents like ether. Plants containing large amounts of raphides are generally acrid and unpalatable. However, it is not always possible to detect the presence of raphides through taste alone. In some tubers such as the Indian turnip which contain large quantities of raphides, the roots are not unpalatable when cooked because the raphides are bound within a matrix of starch which prevents the tongue from sensing their presence. Some other plants store raphides in mucilaginous environments and also do not taste acrid.<ref name="weber" />

There is some doubt about the role of raphides in defense against herbivory. Insects are only rarely affected by them, and no more than by sand. Ruminants are not harmed by them, because certain bacteria in their rumen help to degrade oxalate.{{sfn|Sousa Paiva|2021}}

==Plants containing raphides== Common names vary. The following list is incomplete. Raphides are found in many species in the families Araceae and Commelinaceae, but are also found in a few species in a number of other families.{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} {{div col|colwidth=20em}} Acanthaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Strobilanthes barbata'' (stem, leaf) * ''Strobilanthes callosa'' (stem, leaf) * ''Strobilanthes ciliata'' (stem, leaf) * ''Strobilanthes heyneana'' (leaf) * ''Strobilanthes integrifolia'' (stem, leaf) * ''Strobilanthes lupulina'' (stem, leaf) * ''Strobilanthes reticulata'' (stem, leaf) * ''Strobilanthes sessilis'' (stem, leaf) * ''Thunbergia erecta'' (stem, leaf) * ''Thunbergia laurifolia'' (stem, leaf)

Actinidiaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Actinidia arguta'' (root, flower, fruit) * ''Actinidia callosa'' (fruit) * ''Actinidia chinensis'' (root, flower, fruit) * ''Actinidia chrysantha'' (root, fruit) * ''Actinidia deliiosa'' (fruit) * ''Actinidia eriantha'' (fruit) * ''Actinidia fulvicoma'' (fruit) * ''Actinidia glaucophylla'' (fruit) * ''Actinidia hemsleyana'' (root) * ''Actinidia indochinensis'' (fruit) * ''Actinidia lanceolata'' (fruit) * ''Actinidia macrosperma'' (fruit) * ''Actinidia polygama'' (fruit) * ''Actinidia rufa'' (root, fruit) * ''Clematoclethra scandens'' (flower) * ''Saurauia pittieri'' (flower) * ''Saurauia subspinosa'' (flower)

Alstroemeriaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Alstroemeria angustifolia'' (leaf) * ''Alstroemeria aurea'' (leaf) * ''Alstroemeria exserens'' (leaf) * ''Alstroemeria hookeri'' (leaf) * ''Alstroemeria ligtu'' (leaf) * ''Alstroemeria magnifica'' (leaf) * ''Alstroemeria pallida'' (leaf) * ''Alstroemeria pelegrina'' (leaf) * ''Alstroemeria presliana'' (leaf) * ''Alstroemeria pulchra'' (leaf) * ''Alstroemeria versicolor'' (leaf) * ''Bomarea multiflora'' (leaf) * ''Bomarea ovallei'' (leaf)

Amaranthaceae: * ''Beta'' * ''Spinacia''

Amaryllidaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Crinum amabile'' (leaf) * ''Leucojum aestivum'' (leaf) * ''Pancratium sickenbergeri'' (leaf)

Araceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}}{{sfn|Keating|2004}} * ''Alocasia macrorrhizos'' (root, stem, leaf, flower) * ''Amorphophallus bulbifer'' (leaf) * ''Amorphophallus blumei'' (root, leaf) * ''Amorphophallus dunnii'' (leaf) * ''Amorphophallus gallaensis'' (leaf) * ''Amorphophallus konjac'' (leaf) * ''Amorphophallus krausei'' (leaf) * ''Amorphophallus muelleri'' (root, leaf) * ''Amorphophallus paeoniifolius'' (root, leaf) * ''Amorphophallus salmoneus'' (leaf) * ''Amorphophallus sutepensis'' (leaf) * ''Amorphophallus taurostigma'' (leaf) * ''Amorphophallus titanum'' (leaf) * ''Amorphophallus variabilis'' (leaf) * ''Anaphyllopsis americana'' (flower) * ''Anthurium andraeanum'' (leaf, flower) * ''Anthurium acaule'' (flower) * ''Anthurium crystallinum'' (flower) * ''Anthurium cubense'' (flower) * ''Anthurium halmoorei'' (flower) * ''Anthurium harrisii'' (flower) * ''Anthurium jenmannii'' (flower) * ''Anthurium magnificum'' (flower) * ''Anthurium maricense'' (leaf) * ''Anthurium pallidiflorum'' (flower) * ''Anthurium pedatoradiatum'' (flower) * ''Anthurium schlechtendalii'' (flower) * ''Anthurium signatum'' (flower) * ''Anthurium spectabile'' (flower) * ''Anubias heterophylla'' (flower) * ''Arisaema'' * ''Arisarum vulgare'' (flower) * ''Arum pictum'' (flower) * ''Caladium'' * ''Calla palustris'' (flower) * ''Cercestis dinklagei'' (flower) * ''Colocasia affinis'' (stem) * ''Colocasia gigantea'' (stem) * ''Colocasia esculenta'' (root, stem, leaf) * ''Cyrtosperma chamissonis'' (stem) * ''Cyrtosperma johnstonii'' (root, leaf, flower) * ''Cyrtosperma merkusii'' (stem, leaf) * ''Dieffenbachia seguine'' (stem, leaf, flower) * ''Epipremnum'' * ''Lemna minor'' (leaf) * ''Monstera deliciosa'' (fruit) * ''Philodendron adamantinum'' (syn. ''Thaumatophyllum adamantinum'' (flower) * ''Philodendron bipinnatifidum'' (flower) * ''Philodendron brasiliense'' (syn. ''Thaumatophyllum brasiliense'' (flower) * ''Philodendron corcovadense'' (syn. ''Thaumatophyllum corcovadense'' (flower) * ''Philodendron dardanianum'' (syn. ''Thaumatophyllum dardanianum'' (flower) * ''Philodendron lundii'' (syn. ''Thaumatophyllum lundii'' (flower) * ''Philodendron megalophyllum'' (flower) * ''Philodendron moonenii'' (flower) * ''Philodendron oblongum'' (flower) * ''Philodendron paludicola'' (syn. ''Thaumatophyllum paludicola'' (flower) * ''Philodendron pedatum'' (flower) * ''Philodendron petraeum'' (syn. ''Thaumatophyllum petraeum'' (flower) * ''Philodendron propinquum'' (flower) * ''Philodendron saxicola'' (syn. ''Thaumatophyllum saxicola'' (flower) * ''Philodendron speciosum'' (syn. ''Thaumatophyllum speciosum'' (flower) * ''Philodendron tweedieanum'' (syn. ''Thaumatophyllum tweedieanum'' (flower) * ''Philodendron uliginosum'' (syn. ''Thaumatophyllum uliginosum'' (flower) * ''Philodendron undulatum'' (syn. ''Thaumatophyllum undulatum'' (flower) * ''Philodendron williamsii'' (syn. ''Thaumatophyllum williamsii'' (flower) * ''Pinellia ternata'' (stem) * ''Pinellia pedatisecta'' (stem) * ''Pistia stratiotes'' (leaf) * ''Spathiphyllum'' * ''Stenospermation longiopetiolatum'' (flower) * ''Syngonium schottianum'' (flower) * ''Typhonium flagelliforme'' (stem) * ''Xanthosoma sagittifolium'' (root, stem, leaf) * ''Zantedeschia aethiopia'' (flower)

Araliaceae: * ''Brassaia''

Arecaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Acrocomia aculeata'' (root, leaf, flower) * ''Acrocomia crispa'' (root, leaf, flower) * ''Acrocomia emensis'' (root, leaf, flower) * ''Acrocomia glaucensis'' (root, leaf, flower) * ''Acrocomia hassleri'' (root, leaf, flower) * ''Acrocomia intumescens'' (root, leaf, flower) * ''Acrocomia totai'' (root, leaf, flower) * ''Allagoptera campestris'' (leaf) * ''Ammandra decasperma'' (pseudopedicel) * ''Aphandra natalia'' (pseudopedicel) * ''Archontophoenix alexandrae'' (embryo) * ''Areca catechu'' (embryo) * ''Areca macrocalyx'' (embryo) * ''Areca novohibernica'' (embryo) * ''Arenga tremula'' (embryo) * ''Bactris gasipaes'' (fruit) * ''Brassiophoenix dryomphloeides'' (embryo) * ''Butia buenopolensis'' (leaf, flower) * ''Butia campicola'' (leaf) * ''Butia capitata'' (leaf) * ''Butia catarinensis'' (leaf) * ''Butia exospadix'' (leaf) * ''Butia leptospatha'' (leaf) * ''Butia marmorii'' (leaf) * ''Butia microspadix'' (leaf) * ''Butia pubispatha'' (leaf) * ''Calyptrocalyx albertisianus'' (fruit) * ''Calyptrocalyx hollrungii'' (embryo) * ''Calyptrocalyx lepidotus'' (fruit) * ''Calyptrocalyx spicatus'' (embryo) * ''Caryota cumingii'' (embryo) * ''Caryota mitis'' (root, stem, leaf, flower, fruit) * ''Caryota rumphiana'' (stem, leaf) * ''Chamaedorea tepejilote'' (embryo) * ''Cocos nucifera'' (root, stem, leaf) * ''Copernicia tectorum'' (flower, fruit) * ''Cyrtostachys renda'' (embryo) * ''Drymophloeus pachycladus'' (embryo) * ''Drymophloeus subdistichus'' (embryo) * ''Dypsis decaryi'' (embryo) * ''Dypsis leptocheilos'' (embryo) * ''Dypsis lutescens'' (embryo) * ''Euterpe oleracea'' (embryo) * ''Howea fosteriana'' (fruit) * ''Hydriastele rostrata'' (embryo) * ''Hyophorbe verschaffeltii'' * ''Iguanura'' sp. (embryo) * ''Laccospadix australasicus'' (fruit) * ''Linospadix microcaryus'' (fruit) * ''Linospadix monostachyos'' (fruit) * ''Livistonia saribus'' (embryo) * ''Normanbya normanbyi'' (embryo) * ''Oenocarpus bacaba'' (embryo) * ''Oenocarpus bataua'' (embryo) * ''Oncosperma horridum'' (embryo) * ''Oncosperma tigillarium'' (embryo) * ''Pelagodoxa henryana'' (fruit) * ''Pinanga coronata'' (embryo) * ''Pinanga negrosensis'' (embryo) * ''Pinanga malaiana'' (embryo) * ''Pinanga scortechinii'' (embryo) * ''Prestoea acuminata'' (embryo) * ''Ptychosperma caryotoides'' (embryo) * ''Rhapis excelsa'' (embryo) * ''Solfia samoensis'' (embryo)

Aspleniaceae: * ''Asplenium cardiophyllum'' (leaf epidermis)

Asparagaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Agave debilis'' (root, leaf) * ''Agave geminiflora'' (flower) * ''Agave gracillima'' (root, leaf) * ''Agave guerrerensis'' (root, stem, leaf) * ''Agave guttata'' (root, leaf) * ''Agave hauniensis'' (root, leaf) * ''Agave howardii'' (flower) * ''Agave longiflora'' (root, stem, leaf) * ''Agave multicolor'' (flower) * ''Agave nanchititlensis'' (root, leaf) * ''Agave neonelsonii'' (flower) * ''Agave parrasana'' (leaf) * ''Agave platyphylla'' (flower) * ''Agave polycantha'' (flower) * ''Agave potosina'' (root, stem, leaf) * ''Agave pratensis'' (root, leaf) * ''Agave scabra'' (root, leaf) * ''Agave singuliflora'' (root, leaf) * ''Agave stictata'' (root, leaf) * ''Agave tequilana'' (root, leaf) * ''Agave victoriae-reginae'' (leaf) * ''Bellevalia paradoxa'' (leaf) * ''Chlorophytum orchidastrum'' * ''Cordyline terminalis'' (root, stem, leaf) * ''Dracaena sanderiana'' (leaf) * ''Hyacinthella nervosa'' (leaf) * ''Hyacinthella hispida'' (leaf) * ''Hyacinthella siirtensis'' (leaf) * ''Hyacinthella venusta'' (leaf) * ''Ornithogalum alpiganum'' (stem, leaf) * ''Ornithogalum caudatum'' (flower) * ''Polygonatum odoratum'' (leaf) * ''Polygonatum prattii'' (leaf) * ''Triteleia crocea'' (ovary) * ''Triteleia dudleyi'' (ovary) * ''Triteleia hendersonii'' (ovary) * ''Triteleia hyacintha'' (ovary) * ''Triteleia ixioides'' (ovary) * ''Triteleia laxa'' (ovary) * ''Yucca treculiana'' (root)

Asphodelaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Aloe harlana'' (leaf) * ''Aloe nobilis'' (leaf) * ''Asphodelus aestivus'' (root) * ''Gasteria obliqua'' (leaf) * ''Haworthia cymbiformis'' (leaf)

Asteraceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Aster warmingii'' (root) * ''Baccharis glaziovii'' (stem) * ''Silybum marianum'' (stem) * ''Solidago chilensis'' (stem)

Balsaminaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Impatiens arguta'' (stem) * ''Impatiens balfourii'' (stem, leaf, flower) * ''Impatiens niamniamensis'' (stem) * ''Impatiens parviflora'' (flower) * ''Impatiens thomsonii'' (stem, leaf, flower)

Boraginaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Onosma mollis'' (leaf) * ''Onosma sorgeri'' (leaf)

Bromeliaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * very widespread

Cactaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * widespread

Colchicaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Colchicum kurdi'' (root)

Commelinaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Cochliostema odoratissimum'' (stem, leaf, flower) * ''Commelina coelestis'' (pollen) * ''Commelina tuberosa'' (pollen) * ''Dichorisandra thyrsiflora'' (anther) * ''Tinantia anomala'' (root, leaf, flower) * ''Tinantia pringlei'' (root, leaf, flower) * ''Tradescantia ohiensis'' (stem) * ''Tradescantia pallida'' (anther) * ''Tradescantia spathacea'' (anther) * ''Triceratella''

Cucurbitaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Momordica dioica'' (stem) * ''Momordica cochinchinensis'' (stem)

Dioscoreaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Dioscorea bulbifera'' (root, bulbil) * ''Dioscorea esculenta'' (root) * ''Dioscorea hispida'' (root, petiole) * ''Dioscorea japonica'' (root) * ''Dioscorea polystachya'' (root, stem)

Ebenaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Diospyros montana'' (bark, fruit)

Euphorbiaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Ricinus communis'' (leaf)

Fabaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Acacia robeorum'' (stem, leaf) * ''Medicago truncatula'' (leaf) * ''Pachyrhizus tuberosus'' (root)

Haemodoraceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Anigozanthos flavidus'' (leaf, flower) * ''Conostylis candicans'' (flower)

Heliconiaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Heliconia indica'' (root, flower, fruit) * ''Heliconia longiflora'' (leaf)

Hydrangeaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Hydrangea macrophylla'' (leaf)

Lamiaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Satureja khuzestanica'' (leaf)

Liliaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Drimia maritima'' (leaf, flower bud)

Lowiaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Orchidantha maxillarioides'' (stem, leaf)

Marcgraviaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * very widespread

Musaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Musa acuminata'' (leaf, fruit) * ''Musa ingens'' (leaf, flower) * ''Musa maclayi'' (leaf, flower, fruit)

Nyctaginaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Bougainvillea glabra'' (leaf) * ''Bougainvillea spectabilis'' (leaf)

Oleaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * very widespread

Onagraceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Epilobium tibetanum'' (leaf) * ''Ludwigia peploides'' (leaf)

Orchidaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * very widespread

Pandanaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Pandanus dubius'' (wood) * ''Pandanus leram'' (leaf) * ''Pandanus tectorius'' (wood)

Passifloraceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Passiflora cincinnata'' (fruit)

Philydraceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Heimholtzia glaberrima''

Poaceae: * ''Cenchrus echinatus''

Polygonaceae: * ''Rheum rhabarbarum''

Pontederiaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Monochoria africana'' (anther) * ''Pontederia cordata'' (root) * ''Pontederia crassipes'' (stem)

Roridulaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Roridula gorgonias'' (flower)

Rosaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Rubus alutaceus'' (leaf)

Rubiaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * very widespread

Tetrameristaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Pelliciera rhizophorae'' (stem, flower) * ''Pentamerista neotropica'' (flower) * ''Tetramerista glabra'' (stem)

Typhaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Typha angustifolia'' (leaf) * ''Typha latifolia'' (leaf)

Vitaceae:{{sfn|Lawrie|Medrano Cuetos|Sini|Salam|2023}} * ''Cissus alata'' (leaf) * ''Cissus discolor'' (leaf) * ''Cissus quadrangularis'' (leaf) * ''Cissus repanda'' (leaf) * ''Cissus rotundifolia'' (leaf) * ''Parthenocissus quinquefolia'' (leaf) * ''Parthenocissus tricuspidata'' (leaf) * ''Parthenocissus vitacea'' (leaf) * ''Rhoicissus tomentosa'' (leaf) * ''Tetrastigma voinierianum'' (leaf) * ''Vitis berlandieri'' (root) * ''Vitis rupestris'' (anther) * ''Vitis vinifera'' (leaf) {{div col end}}

== See also == * Calcium oxalate * Druse * Phytolith * Plant defense against herbivory

== References == {{reflist}}

==Bibliography== * {{cite journal |date=2023-06-06 |first1=Natasha S. |last1=Lawrie |first2=Nekane |last2=Medrano Cuetos |first3=Francesca |last3=Sini |first4=Ghifary A. |last4=Salam |first5=Hangyu |last5=Ding |first6=Arthur |last6=Vancolen |first7=Jessica M. |last7=Nelson |first8=Roy H. J. |last8=Erkens |first9=Giuditta |last9=Perversi |title=Systematic review on raphide morphotype calcium oxalate crystals in angiosperms |url=https://academic.oup.com/aobpla/article/15/4/plad031/7190693 |doi=10.1093/aobpla/plad031 |journal=AoB Plants |eissn=2041-2851 |volume=15 |issue=4|article-number=plad031 |pmid=37554287 |pmc=10406436 }} See ''Supporting Information''. * {{cite journal |date=2021-05-27 |first=Élder Antônio |last=Sousa Paiva |title=Do calcium oxalate crystals protect against herbivory? |doi=10.1007/s00114-021-01735-z |journal=Concepts & Synthesis |eissn=1947-9468 |volume=108|issue=3 |article-number=24 |pmid=34043088 |bibcode=2021SciNa.108...24P }} * {{Cite journal |year=2004 |last=Keating |first=Richard C. |title=Systematic Occurrence of Raphide Crystals in Araceae. |journal=Annals of the Missouri Botanical Garden |language=en |volume=91 |issue=3 |pages=495–504 |jstor=3298626}}

Category:Plant physiology Category:Oxalate minerals Category:Organic minerals Category:Plant toxins