{{Short description|Genus of fungi}} {{Automatic_taxobox | image = Nidula_candida.jpg | image_caption = ''Nidula candida'' | taxon = Nidula | authority = V.S.White (1902) | type_species = ''Nidula candida'' | type_species_authority = (Peck) V.S.White (1902) | subdivision_ranks = Species | subdivision = †''N. baltica''<br> ''N. candida''<br> ''N. emodensis''<br> ''N. macrocarpa''<br> ''N. niveotomentosa''<br> ''N. shingbaensis'' }}
'''''Nidula''''' is a genus of fungi in the family Agaricaceae. Their fruit bodies resemble tiny egg-filled birds' nests, from which they derive their common name "bird's nest fungi". Originally described in 1902, the genus differs from the related genera ''Cyathus'' and ''Crucibulum'' by the absence of a cord that attaches the eggs to the inside of the fruit body. The life cycle of this genus allows it to reproduce both sexually, with meiosis, and asexually via spores.
Species in this genus produce a number of bioactive compounds, including 4-(''p''-hydroxyphenyl)-2-butanone, a major component of raspberry flavor and insect attractor used in pesticides.
==Taxonomy== The genus ''Nidula'' was originally proposed by Violet S. White in her monograph on the North American species of the Nidulariaceae, and included the species ''N. candida'' and ''N. microcarpa''.<ref name="White 1902"/> The genus name is derived from the Latin ''nidula'', meaning "little nest".<ref name="Brodie142">Brodie, ''The Bird's Nest Fungi'', p. 142.</ref> Although originally classified in the family Nidulariaceae, molecular phylogenetics demonstrated that the Nidulariaceae are part of the agaricoid clade,<ref name="Matheny 2006"/> and ''Nidula'' was later transferred to the family Agaricaceae.<ref name="Kirk 2008"/>
==Description== The fruit bodies (''peridia'') of ''Nidula'' species are typically 3–8 mm in diameter, 5–15 mm tall, and cup- or urn-shaped—having almost vertical sides with the lip flared outwards. Depending on the species, the color may range from white, grey, buff, or tawny.<ref name="Brodie142" /> The peridia are covered on the external surface with closely matted, shaggy hairs, technically called a tomentum. Immature peridia have a membrane covering the mouth (an ''epiphragm''), which later ruptures into 4–7 lobes when mature. The "eggs", or peridioles, are numerous, grey-brown or reddish-brown in color, and embedded in a gelatinous matrix when young and fresh. In contrast to other genera of the Nidulariaceae, such as ''Cyathus'' or ''Crucibulum'', the peridioles of the ''Nidula'' are not attached to the peridia by a cord of mycelia known as a funiculus. The spores are ovoid to elliptical in shape, thick-walled, light brown, and have dimensions of 8–10 by 4–6 μm.<ref name="Miller 1988"/>
=== Life cycle === The life cycle of the genus ''Nidula'', which contains both haploid and diploid stages, is typical of taxa in the basidiomycetes that can reproduce both asexually (via vegetative spores), or sexually (with meiosis). Basidiospores produced in the peridioles each contain a single haploid nucleus. After dispersal, the spores germinate and grow into homokaryotic hyphae, with a single nucleus in each compartment. When two homokaryotic hyphae of different mating compatibility groups fuse with one another, they form a dikaryotic mycelia in a process called plasmogamy. Like other members of the Nidulariaceae, species in ''Nidula'' have a heterothallic (bifactorial) mating system.<ref name="Brodie 1951" /> After a period of time and under the appropriate environmental conditions, fruit bodies may be formed from the dikaryotic mycelia. These fruit bodies produce peridioles containing the basidia upon which new basidiospores are made. Young basidia contain a pair of haploid sexually compatible nuclei which fuse, and the resulting diploid fusion nucleus undergoes meiosis to produce haploid basidiospores.<ref name="Deacon 2005" />
== Species == There are five extant and one extinct species of ''Nidula'':
* ''N. baltica'' :Described in 2014 from a fossil found in Baltic amber.<ref name="Poinar 2014" />
* ''N. candida''<ref name="White 1902" /> : Peridia are 10 to 15 mm tall, grey to dark buff, with a recurved rim at maturity. The peridioles are 1.5–2 mm wide, and light grey-brown, and smooth. The spores are elliptical, with dimensions of 4–6 by 8–10 μm.<ref name="Brodie144">Brodie, ''The Bird's Nest Fungi'', p. 144.</ref>
* ''N. macrocarpa'' : Peridia are 5 to 10 mm tall, and white to yellowish in color; the rim is either straight or slightly recurved. Peridioles are 0.5 to 1 mm wide, wrinkled, and colored red-brown. Spores are elliptical or roughly spherical, with dimensions of 6–9 by 5–6 μm.<ref name="Brodie143">Brodie, ''The Bird's Nest Fungi'', p. 143.</ref>
thumb|right|150px|''N. niveo-tomentosa''
* ''N. niveo-tomentosa'' : Peridia are 4–6 mm tall with rims that have a fringe of white hairs. Peridioles are mahogany-brown and 0.5–1 mm wide. Spores have an elliptical or roughly spherical shape, and are 6–9 by 5–6 μm.<ref name="Brodie143" />
* ''N. emodensis''<ref name="Lloyd 1906" /> : Peridia are 4–6 mm tall by 4–5 mm wide at the mouth. The exterior surface is a grey color, the interior smooth and whitish. Peridioles are reddish-brown to black, have minute wrinkles, and dimensions of 0.5–1 mm. The spores are somewhat elliptical, obovate, or pyriform.<ref name="Brodie144" />
* ''N. shingbaensis'' :Peridia are 6–9 mm tall by 5–7 mm wide at the mouth. Found in India, it differs from other ''Nidula'' in having a six-layered peridium.<ref name="Das 2013" />
==Habitat and distribution== Species in ''Nidula'' have been found in North America, the Himalayas, and mountains in Japan. ''N. niveo-tomentosa'' has been collected at an elevation of {{convert|5000|ft|m}} on Blue Mountains in Jamaica.<ref name="Brodie 1951"/>
==Bioactive compounds== The ''Nidula'' are known to produce a number of bioactive compounds. ''N. niveo-tomentosa'' grown in liquid culture makes niduloic acid (3-hydroxy-5-(''p''-hydroxyphenol)pentanoic acid), 4-(''p''-hydroxyphenyl)-2-butanol, ''trans''-4-''p''-hydroxyphenylbut-3-en-2-one, 4-(3',4'-dihydroxyphenyl)-2-butanol, 4-(3',4'-dihydroxyphenyl)-2-butanone, zingerone, 3-(''p''-hydroxyphenyl)-1,2-propanediol, and 4-(''p''-hydroxyphenyl)-2-butanone.<ref name="Ayer 1980"/> The latter compound is commonly known as "raspberry ketone", one of the major chemicals contributing to the flavour of raspberries.<ref name="Boker 2001"/> This chemical is used (in its acetate form) as an insect attractor in the pesticide Cue-lure,<ref name="Ayer 1980" /> structurally related to the sex pheromone that female melon flies (sp. ''Bactrocera cucurbitae'') use to attract males for mating.<ref name="US EPA"/>
''Nidula candida'' contains the sesquiterpene compounds nidulal and niduloic acid, both of which have weak cytotoxic and antibiotic activities.<ref name="Erkel 1996"/>
==References== {{Reflist|colwidth=30em|refs=
<ref name="Ayer 1980">{{cite journal |title=Phenolic metabolites of the bird's nest fungus ''Nidula niveo-tomentosa'' |vauthors=Ayer WA, Singer PP |year=1980 |journal=Phytochemistry |volume=19 |issue=12 |pages=2717–21 |doi=10.1016/S0031-9422(00)83949-7|bibcode=1980PChem..19.2717A }}</ref>
<ref name="Boker 2001">{{cite journal |vauthors=Böker A, Fischer M, Berger RG |title=Raspberry ketone from submerged cultured cells of the basidiomycete ''Nidula niveo-tomentosa'' |journal= Biotechnology Progress|volume=17 |issue=3 |pages=568–72 |year=2001 |pmid=11386881 |doi=10.1021/bp010011b|s2cid=33371093 |doi-access=free }}</ref>
<ref name="Brodie 1951">{{cite journal |title=Two heterothallic species of the genus ''Nidula'' |author=Brodie HJ. |year=1951 |journal=Mycologia |volume=43 |issue=3 |pages=329–37 |url=http://www.cybertruffle.org.uk/cyberliber/59350/0043/003/0329.htm |doi=10.2307/3755596|jstor=3755596 |url-access=subscription }}</ref>
<ref name="Das 2013">{{cite journal |vauthors=Das K, Zhao RL |title=''Nidula shingbaensis'' sp. nov., a new bird's nest fungus from India |journal=Mycotaxon |year=2013 |volume=125 |pages=53–8 |doi=10.5248/125.53|doi-access=free }}</ref>
<ref name="Deacon 2005">{{cite book |author=Deacon J.|title=Fungal Biology |publisher=Blackwell Publishers |location=Cambridge, Massachusetts |year=2005 |pages=31–2 |isbn=1-4051-3066-0}}</ref>
<ref name="Erkel 1996">{{cite journal |vauthors=Erkel G, Becker U, Anke T, Sterner O |title=Nidulal, a novel inducer of differentiation of human promyelocytic leukemia cells from ''Nidula candida'' |journal=Journal of Antibiotics |volume=49 |issue=12 |pages=1189–95 |date=December 1996 |pmid=9031663 |doi=10.1002/chin.199725178}}</ref>
<ref name="Kirk 2008">{{cite book |vauthors=Kirk PM, Cannon PF, Minter DW, Stalpers JA |title=Dictionary of the Fungi |edition=10th |publisher=CAB International |location=Wallingford, UK |year=2008 |isbn=978-0-85199-826-8}}</ref>
<ref name="Lloyd 1906">{{cite journal |author=Lloyd CG. |author-link=Curtis Gates Lloyd |year=1906 |title=The Nidulariaceae |journal=Mycological Writings |volume=2 |pages=1–30 }}</ref>
<ref name="Matheny 2006">{{cite journal |vauthors=Matheny PB, Curtis JM, Hofstetter V, Aime MC, Moncalvo JM, Ge ZW, Yang ZL, Slot JC, Ammirati JF, Baroni TJ, Bougher NL, Hughes KW, Lodge DJ, Kerrigan RW, Seidl MT, Aanen DK, DeNitis M, Daniele GM, Desjardin DE, Kropp BR, Norvell LL, Parker A, Vellinga EG, Vilgalys R, Hibbett DS |year=2006 |title=Major clades of Agaricales: a multilocus phylogenetic overview |journal=Mycologia |volume=98 |issue=6 |pages=982–95 |pmid=17486974 |doi=10.3852/mycologia.98.6.982 }}</ref>
<ref name="Miller 1988">{{cite book |vauthors=Miller HR, Miller OK |title=Gasteromycetes: Morphological and Developmental Features, with Keys to the Orders, Families, and Genera |publisher=Mad River Press |location=Eureka, California |year=1988 |page=71 |isbn=0-916422-74-7}}</ref>
<ref name="Poinar 2014">{{cite journal |author=Poinar G Jr. |title=Bird's nest fungi (Nidulariales: Nidulariaceae) in Baltic and Dominican amber |journal=Fungal Biology |year=2014 |volume=118 |issue=3 |pages=325–9 |doi=10.1016/j.funbio.2014.01.004|pmid=24607356 }}</ref>
<ref name="US EPA">{{cite web |url=http://www.epa.gov/opp00001/biopesticides/ingredients/factsheets/factsheet_128916.htm |title=Cuelure <nowiki>(4-[p-Acetoxyphenyl]-2-butanone)</nowiki> (128916) Fact sheet | Pesticides | US EPA |access-date=2009-03-20}}{{dead link|date=July 2025|bot=medic}}{{cbignore|bot=medic}}</ref>
<ref name="White 1902">{{cite journal |author=White VS. |year=1902 |title=The Nidulariaceae of North America |journal=Bulletin of the Torrey Botanical Club |volume=29 |issue=5 |pages=251–80 |doi=10.2307/2478721 |jstor=2478721}}</ref>
}}
===Cited works=== *{{cite book |author=Brodie HJ. |title=The Bird's Nest Fungi |publisher=University of Toronto Press |location=Toronto |year=1975 |isbn=0-8020-5307-6}}
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Category:Agaricaceae Category:Agaricales genera