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Setaria pumila (Poir.) Roem. & Schult. subsp. pumila

Overview
General Information
ID Info
Similar Species
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Aperçu
Renseignements Généraux
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Espèces Semblables
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Family :

Famille :

Poaceae

Synonym(s) :

Synonyme(s) :

Panicum pumilum Poir. (basionym) (POWO 2024; USDA-ARS 2024)
Chaetochloa glauca (L.) Scribn. (USDA-NRCS 2024)
Chaetochloa lutescens (Weigel) Stuntz (USDA-NRCS 2024)
Chaetochloa lutescens Stuntz (USDA-ARS 2024)
Panicum glaucum L. (USDA-NRCS 2024)
Panicum glaucum var. pumilum (Poir.) Asch. & Graebn. (POWO 2024)
Panicum lutescens Weigel, nom. inval. (USDA-ARS 2024)
Setaria glauca (L.) P. Beauv. (USDA-NRCS 2024)
Setaria glauca auct. (USDA-ARS 2024)
Setaria glauca sensu Vickery (USDA-NRCS 2024)
Setaria glauca var. pumila (Poir.) Hegi (POWO 2024)
Setaria lutescens (Weigel) F.T. Hubbard (USDA-NRCS 2024)
Setaria lutescens (Stuntz) F. T. Hubb. (USDA-ARS 2024)
Setaria lutescens f. pumila (Poir.) Soó (POWO 2024)

Common Name(s) :

Nom(s) commun(s) :

Yellow foxtail

(English) (Barkworth et al. 2003; DiTomaso and Healy 2007; AOSA 2024; USDA-ARS 2024)
Yellow bristlegrass (English) (AOSA 2024)
Yellow bristle grass (English) (DiTomaso and Healy 2007; USDA-ARS 2024)
Pigeon grass (English) (Barkworth et al. 2003)
Pale pigeon grass (English) (ALA 2024)
Setaire glauque (French) (Barkworth et al. 2003)

Setaria pumila subsp. pumila   (yellow foxtail) spikelets

  • Setaria pumila subsp. pumila   (yellow foxtail) spikelets

  • Setaria pumila subsp. pumila   (yellow foxtail) spikelet

  • Setaria pumila subsp. pumila   (yellow foxtail)floret, palea view

  • Setaria pumila subsp. pumila   (yellow foxtail) floret, lemma view

  • Setaria pumila subsp. pumila   (yellow foxtail) floret; side view

  • Setaria pumila subsp. pumila  (yellow foxtail)

  • Setaria pumila subsp. pumila  (yellow foxtail)

  • Setaria pumila subsp. pumila   (yellow foxtail)

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Overview

Aperçu

Regulation :

Remarques Réglementation:

  • Quarantine lists of countries e.g. Mexico *may be updated without notice

Regulation Notes:

  • Setaria pumila is on the lists of harmful organisms for Guatemala, Honduras, and Mexico (USDA-PCIT 2024) (*may be updated without notice).
  • Setaria lutescens (a synonym of Setaria pumila subsp. pumila) is on the list of harmful organisms for New Zealand (USDA-PCIT 2024) (*may be updated without notice).

Distribution :

Répartition :

The exact native range of Setaria pumila subsp. pumila is obscure partly due to past nomenclatural confusion (USDA-ARS 2024). The subspecies is believed to be native to northern Africa, the Azores and Canary Islands, southern and eastern Europe, western temperate Asia, northern India and Pakistan, and northern Asia (parts of eastern Russia, Mongolia, China, Japan, and Korea) (Lucid Central 2016). S. pumila subsp. pumila is reported as naturalized in Australia, New Zealand, Canada, and the United States, and it occurs in many other places (POWO 2024; USDA-ARS 2024; James n.d.).

Habitat and Crop Association :

Habitat et Cultures Associées :

Setaria pumila subsp. pumila can be found in lawns, gardens, fields, pastures, and along gravely riverbanks, roadsides and railroad tracks, and in other disturbed sites (James n.d.; MWI 2024; NCSE 2024).

This subspecies can be found as a contaminant in many agriculture crops, such as Helianthus annuus L. (sunflower), Linum usitatissimum L. (flax), Medicago sativa L. (lucerne), Sorghum bicolor L. (sorghum), Triticum aestivum L. (wheat), and Zea mays L. (maize) (CABI 2021).

Economic Use, cultivation area, and Weed Association :

Utilisation économique, zone de culture et association de mauvaises herbes :

Duration of Life Cycle :

Durée du cycle vital:

Annual

Dispersal Unit Type :

Type d’unité de dispersion :

Spikelet, floret, caryopsis

General Information

RENSEIGNEMENTS GÉNÉRAUX

Setaria is a genus of about 140 species found primarily in tropical and warm-temperate regions (Barkworth et al. 2003). Reproduction in S. pumila subsp. pumila occurs only by seed (i.e., caryopsis bearing spikelet). Freshly matured seeds are usually dormant and may require two to four months of after-ripening prior to germination (DiTomaso and Healy 2007). Seed buried in soil may remain viable for 12 – 30 years (DiTomaso and Healy 2007). Seeds can spread via water, animals, contaminated farm or earth moving equipment, or as hay or seed lot contaminants.

The leaves of S. pumila subsp. pumila provides palatable forage for small mammals and livestock; however, the mature bristly seed heads may cause injury to the mouths of horses and cattle (Stubbendieck et al. 1995; NCSE 2024). The seeds provide valuable food, and the plants provide ground cover for wild birds (Stubbendieck et al. 1995).

Caution should be taken when reviewing the literature for S. pumila. Some authors do not recognize subspecies, such as Setaria pumila subsp. pallide-fusca [Setaria pallidefusca (Schumach.) Stapf & C.E. Hubbard], cattail grass, as distinct from the species, while others consider this subspecies a noxious or harmful weed (Scher et al. 2015; CABI 2021; NCSE 2024; POWO 2024; USDA-AMS 2024; USDA-ARS 2024; USDA-NRCS 2024; USDA-PCIT 2024).

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Setaria pumila in a pasture in Poland. Photo by By Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0, Wikimedia

Identification

Identification

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  • Spikelet

    Size

    • Spikelet length*: 2.7 – 3.4 (average 3.1) mm; width*: 1.6 – 2.2 mm (average 2.0 mm); thickness*: 1.3 – 2.2 mm (average 1.5 mm).
    • Spikelet length**: 2.8 – 3.5 mm; width**: 1.8 – 2.2 mm.
    • Lower (1st) glume length*: 1.2 – 2.0 mm (average 1.7 mm); about one-third to one-half the length of the spikelet (eFloras 2024).
    • Upper (2nd) glume length*: 1.7 – 2.4 mm (average 2.1 mm); one-half to two-thirds the length of the spikelet. (Tutin et al. 1980).
    *Note: minimum and maximum based on a random selection of 21 spikelets in normal range of this species using image measurement protocol (ISMA 2020). Measurements by D. Meyer, CDA-S-25245 and CDA-S-25247.
    **Note: minimum and maximum based on a random selection of 10 spikelets in normal range of this species using image measurement protocol (ISMA 2020). Measurements by CFIA Lab.

    Measurements from the literature:
    • Spikelet length: 2.7 – 3.3 mm (Tutin et al. 1980).
    • Spikelet length: 3 – 3.4 mm (Barkworth et al. 2003).
    • Spikelet length: 3 – 3.5 mm, width 1.5 – 2.2 mm, thickness 1.2 – 1.6 mm (Walters 2011).

    Shape

    • Spikelet broadly oval to egg-shaped; dorsoventrally compressed, one side strongly arched and the other side flat (planoconvex; D-shaped in lateral view), thickest near the middle.
    • Lower (1st) glume broadly triangular, the outer corners wrapping around the base of the upper glume.
    • Upper (2nd) glume broadly egg-shaped.

    Surface Texture

    • Texture of glumes thin and papery.
    • Lower (1st) glume 3-veined.
    • Upper (2nd) glume 5-veined.

    Colour

    • Glumes light green to light brownish- or whitish-yellow coloured.

    Other Features

    • The spikelet consists of a pair or glumes, one sterile floret, and one fertile floret.
    • Disarticulation occurs below the glumes; the spikelet falls as a unit from the plant.

    Setaria pumila subsp. pumila   (yellow foxtail) spikelets

  • Sterile floret

    Size

    • Sterile floret lemma length*: 2.5 – 3.4 mm (average 2.9 mm).
    • Sterile floret palea length nearly equal to the sterile lemma.
    *Note: minimum and maximum based on a random selection of 21 sterile florets in normal range of this species using image measurement protocol (ISMA 2020). CDA-S-25245 and CDA-S-25247.

    Shape

    • Sterile floret egg-shaped.

    Surface Texture

    • Sterile lemma thin and papery, similar to the glumes.
    • Sterile lemma 5-nerved.
    • Sterile palea membranous and translucent.

    Colour

    • Sterile lemma light green to light brownish- or whitish-yellow coloured.

    Other Features

    • Sterile floret equal to length of spikelet, palea +/- equal in length to sterile lemma, hyaline

    Setaria pumila subsp. pumila  (yellow foxtail)

  • Fertile floret

    Size

    • Fertile floret length*: 2.7 – 3.4 mm; width*: 1.6 – 2.2 mm (average 2.0 mm); thickness*: 1.3 – 1.7 (average 1.5 mm).
    *Note: minimum and maximum based on a random selection of 21 fertile florets in normal range of this species using image measurement protocol (ISMA 2020). CDA-S-25245 and CDA-S-25247.

    Measurements from the literature:
    • Fertile floret length: 1.5 – 3.5 mm (Walters 2011).

    Shape

    • Fertile floret broadly oval to egg-shaped broadly oval to egg-shaped in outline, tip slightly pointed and three-parted.
    • Fertile floret dorsoventrally compressed, one side strongly arched and the other side flat (D-shaped in lateral view), thickest near the middle.
    • Lemma margin in-rolled over palea margin forming a thick rim on the palea side of the floret.

    Surface Texture

    • Fertile lemma and palea hardened (indurate).
    • Fertile lemma strongly transverse ridged over entire surface.
    • Fertile palea tuberculate between the keels and smooth and glossy from the keels to the margins. The glossy portion concealed by the lemma.

    Colour

    • Fertile floret whitish-yellow, greyish yellow to dark brown coloured.

    Other Features

    • Fertile floret does not have an awn.

    Setaria pumila subsp. pumila   (yellow foxtail)floret, palea view

  • Caryopsis

    Size

    • Caryopsis length*: 1.9 – 2.3 mm (average 2.1 mm); width*: 1.4 – 1.6 mm (average 1.5).
    *Note: minimum and maximum based on a random selection of 7 caryopses in normal range of this species using image measurement protocol (ISMA 2020). CDA-S-25245 and CDA-S-25247.

    Measurements from the literature:
    • Caryopsis length: 1.5 – 2.0 mm; width 0.9 – 1.0 mm (Walters 2011).

    Shape

    • Caryopsis oval to egg-shaped in outline, dorsoventrally.

    Surface Texture

    • Caryopsis surface generally smooth, embryo areas wrinkled.

    Colour

    • Caryopsis is dull greyish or greenish white coloured.

    Other Features

    • Hilum is a dark oval spot near base of the caryopsis on the side opposite the embryo.

    Setaria pumila subsp. pumila  (yellow foxtail)

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  • Embryo

    Size

    • Embryo length*: 1.9 – 2.3 mm; width*: 1.4 – 1.6 mm (average 1.5 mm).
    • Embryo about three-fourths the length of the caryopsis.
    *Note: minimum and maximum based on a random selection of 7 embryos in normal range of this species using image measurement protocol (ISMA 2020). CDA-S-25245 and CDA-S-25247.

    Shape

    • Embryo egg-shaped in outline.

    Endosperm

    • Endosperm solid (Terrell 1977).

    Other Features

    • Embryo in lateral position (Martin 1946).

Identification Tips

CONSEILS POUR L’IDENTIFICATION

Setaria pumila subsp. pumila is in the Paniceae tribe of Poaceae (Barkworth et al. 2003).

  • The dispersal unit is a spikelet that has two florets, one sterile and one fertile.
  • The spikelet is egg-shaped or teardrop-shaped in outline.
  • The thin papery glumes are unequal in length.
  • The lower (1st) glume is somewhat triangular, and wraps around the upper (2nd) glume, and is usually one-half as long as the spikelet.
  • The upper (2nd) glume and the sterile floret lemma are as long as the spikelet and are similar in texture.
  • The fertile lemma and palea are hardened.
  • The fertile lemma surface is strongly transverse ridged.
  • The exposed portion of the palea is tuberculate.
  • The palea margins are concealed by the in-rolled lemma margins that form a thick rim on the palea side of the floret.

Setaria pumila subsp. pumila   (yellow foxtail)floret, palea view

Additional Botany Information

AUTRES RENSEIGNEMENTS BOTANIQUES

Flowers/Inflorescence

  • The inflorescence is a spike-like panicle, cylindrical, up to 15 cm long, usually erect (Tutin et al. 1980; Barkworth et al. 2003).
  • Panicle branches are very short, densely crowded, each usually bearing one spikelet, and occasionally a second aborted spikelet (MWI 2024).
  • Each spikelet is subtended by 4 – 12 awn-like, yellow to golden brown (rarely purplish) bristles (Tutin et al. 1980; Barkworth et al. 2003; MWI 2024).
  • The bristles are 3 – 8 mm long, antrorsely barbed (i.e., barbs are pointed toward the tip of the bristle) (Tutin et al. 1980; Barkworth et al. 2003).
  • Mature spikelets break away from the plant as a unit while the bristles remain attached to the plant (Tutin et al. 1980; DiTomaso and Healy 2007).

Vegetative Features

  • Stems up to 130 cm tall (Tutin et al. 1980).
  • Stems flattened in cross-section (DiTomaso and Healy 2007).
  • Roots are fibrous, tillers will produce roots at the base of the plant (Neal et al. 2023).
  • Leaf sheaths glabrous (Barkworth et al. 2003).
  • Ligules a fringe of hairs, 0.5 – 1 mm long (Barkworth et al. 2003; Di Tomaso and Healy 2007).
  • Leaf blades keeled and slightly twisted, up to 30 cm long and 2 – 10 mm wide, upper surface glabrous except with long hairs at the bases and lower margins (Tutin et al. 1980; DiTomaso and Healy 2007).

Setaria pumila plants with erect or nodding inflorescences in flower, showing waxy blue-green linear leaves that taper to the tip. Photo by Lyrae Willis.

Similar Species

ESPÈCES SEMBLABLES

Similar species are based on a study of seed morphology of various species, and those with similar dispersal units are identified. The study is limited by physical specimen and literature availability at the time of examination, and possibly impacted by the subjectivity of the authors based on their knowledge and experience. Providing similar species information for seed identification is to make users aware of similarities that could possibly result in misidentification.

Setaria faberi R. A. W. Herrm.
Giant foxtail (Darbyshire 2003; AOSA 2024)
Chinese foxtail (Barkworth et al. 2003)
Japanese bristlegrass (USDA-NRCS 2024)
Nodding bristle grass (USDA-ARS 2024)

  • The upper (2nd) glume in S. faberi is three-quarters the length of the spikelet or less, while in S. pumila subsp. pumila the upper glume is usually one-half (sometimes two-thirds) the length of the spikelet.
  • The fertile lemma in S. faberi is narrowly transverse ridged in the lower two-thirds, becoming smoother toward the lemma tip, whereas in S. pumila subsp. pumila the ridges are thicker and continue all the way to the lemma tip.
  • The glossy margins of the fertile palea are exposed in S. faberi and they are concealed by the lemma margins in S. pumila subsp. pumila.

Setaria italica (L.) P. Beauv.
Foxtail millet (Barkworth et al. 2003; AOSA 2024; USDA-NRCS 2024)
Italian millet (AOSA 2024)

  • The spikelets of S. italica tend to be smaller (2 – 3 mm long; 1.5 mm wide; Musil 1963; Barkworth et al. 2003) than those of S. pumila subsp. pumila (2.7 – 3.4 mm long*; 1.6 – 2.2 mm wide*).
  • Surface texture of the fertile lemma in S. italica is minutely tuberculate to smooth, whereas in S. pumila subsp. pumila the fertile lemma is strongly transverse ridged.
  • The glossy margins of the fertile palea are exposed in S. italica and they are concealed by the lemma margins in S. pumila subsp. pumila.
  • In S. italica the fertile florets fall from the plant leaving the glumes, sterile floret, and subtending bristles attached to the plant, whereas in S. pumila subsp. pumila the entire spikelet falls as a unit from the plant (CABI 2021).

Setaria parviflora (Poir.) Kerguélen
Knotroot bristlegrass (AOSA 2024)
Knotroot foxtail (Wiersema and León 1999)
Marsh bristlegrass (USDA-NRCS 2024)
Slender pigeon grass (ALA 2024)

  • The spikelets of S. parviflora are smaller (2 – 2.8 mm long; 1.1 – 1.3 mm wide; Walters 2011), compared to S. pumila subsp. pumila (2.7 – 3.4 mm long*; 1.6 – 2.2 mm wide*).
  • The fertile lemma in S. parviflora is pointed, while it is broadly angled (obtuse) in S. pumila subsp. pumila.

Setaria pumila (Poir.) Roem. & Schult. subsp. pallide-fusca (Schumach.) B. K. Simon
[Panicum pallide-fuscum Schumach.; Setaria glauca (L.) P. Beauv. var. pallide-fusca (Schumach.) T. Koyama; Setaria pallide-fusca (Schumach.) Stapf & C. E. Hubb.] (USDA-ARS 2024)
Cattail grass (Scher et al. 2015; AOSA 2024)

  • Spikelets of S. pumilla subsp. pallide-fusca are generally smaller (2 – 2.8 mm long, 1.1 – 1.7 mm wide, 0.9 – 1.3 mm thick; Scher et al. 2015), whereas S. pumila subsp. pumila spikelets are usually larger (2.7 – 3.4 mm long*, 1.6 – 2.2 wide*, 1.3 – 2.2 mm thick*).
  • In S. pumila subsp. pallide-fusca the transverse ridges on the fertile lemma are widely spaced and are longitudinally striate giving a distinct cross-hatching pattern on the ridges and in the depressions between the ridges; whereas in S. pumila subsp. pumila the transverse ridges are more narrowly spaced and look like lines of tubercules.
*Note: minimum and maximum based on a random selection of 21 spikelets in normal range of S. pumila subsp. pumila using image measurement protocol (ISMA 2020). CDA-S-25245 and CDA-S-25247.

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Reference(s)

Référence(s)

Association of Official Seed Analysts (AOSA). 2024. Rules for Testing Seeds. Vol. 3: Uniform Classification of Weed and Crop Seeds. Association of Official Seed Analysts, Wichita, Kansas.

Atlas of Living Australia (ALA). 2024. Website at  https://www.ala.org.au/ Accessed October 7, 2024.

Barkworth, M. E., Capels, K. M., Long, S., and Piep, M. B. 2003. Flora of North America. Vol. 25, Magnoliophyta: Commelinidae (in part): Poaceae, part 2. Oxford University Press.

Darbyshire, S. J. 2003. Inventory of Canadian Agricultural Weeds Agriculture and Agri-Food Canada. 48.

DiTomaso, J. M. and Healy, E. A. 2007. Weeds of California and Other Western States. Vol. 2: Geraniaceae – Zygophyllaceae. Agriculture and Natural Resources Publication 3488. University of California, Oakland, CA.

eFloras. 2024. Flora of China. Setaria. http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=130214 Accessed October 13, 2024.

International Seed Morphology Association (ISMA). 2020. Method for seed size measurement. Version 1.0. ISMA Publication Guide. https://www.idseed.org/authors/details/method_for_seed_size_measurement.html

James, T. n.d. Yellow Bristle Grass. AgResearch http://www.agresearch.co.nz/our-science/biocontrol-biosecurity/weed-control/Pages/yellow-bristle-grass.aspx

Lucid Central. 2016. Weeds of Australia: Setaria pumila (Poir.) Roem. & Schult. subsp. pumila Fact Sheet. https://keyserver.lucidcentral.org/weeds/data/media/Html/setaria_pumila_subsp._pumila.htm Accessed October 14, 2024.

Martin, A. C. 1946. The comparative internal morphology of seeds. The American Midland Naturalist 36(3):513-660.

Minnesota Wildflowers Information (MWI). 2024. Minnesota Wildflowers: a Field Guide to the Flora of Minnesota. https://www.minnesotawildflowers.info/grass-sedge-rush/yellow-foxtail Accessed October 14, 2024.

Musil, A. F. 1963. Identification of Crop and Weed Seeds. Agriculture Handbook No. 219. United States Department of Agriculture. Washington D.C.

Neal, J. C., Uva, R. H., DiTomaso, J. M., DiTommaso, A. 2023. Weeds of the Northeast. 2nd Ed. Cornell University Press, Ithaca NY.

North Carolina State Extension (NCSE). 2024. North Carolina Extension Gardener Plant Toolbox: Setaria pumila. https://plants.ces.ncsu.edu/plants/setaria-pumila/ Accessed October 15, 2024.

Plants of the World Online (POWO). 2024. Facilitated by the Royal Botanic Gardens, Kew. https://www.plantsoftheworldonline.org/ Accessed October 8, 2024.

Scher, J. L., D. S. Walters, and A.J. Redford. 2015. Federal noxious weed disseminules of the U.S., Edition 2.2. California Department of Food and Agriculture, and USDA APHIS PPQ Identification Technology Program. Fort Collins, CO. https://idtools.org/fnwd/index.cfm?packageID=1097&entityID=2688  Accessed October 15, 2024.

Stubbendieck, J., Friisoe, G. Y., Bolick, M. R. 1995. Weeds of Nebraska and the Great Plains. Nebraska Department of Agriculture.

Terrell, E. E. 1971. Survey of occurrences of liquid or soft endosperm in grass genera. Bull. Torr. Botan. Club 98(5):264-268.

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M., and Webb, D. A. (eds.). 1980. Flora Europaea. Volume 5, Alismataceae to Orchidaceae (Monocotyledones). Cambridge University Press.

United States Department of Agriculture-Agricultural Marketing Service (USDA-AMS). 2024. State Noxious-Weed Seed Requirements Recognized in the Administration of the Federal Seed Act. https://www.ams.usda.gov/sites/default/files/media/StateNoxiousWeedsSeedList.pdf Accessed October 16, 2024.

United States Department of Agriculture-Agricultural Research Services (USDA-ARS). 2024. Germplasm Resources Information Network (GRIN), https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch Accessed October 07, 2024.

United States Department of Agriculture-Natural Resources Conservation Service (USDA-NRCS). 2024. The PLANTS Database. National Plant Data Team, Greensboro, NC USA. https://plants.usda.gov/home Accessed October 7, 2024.

United States Department of Agriculture – Phytosanitary Certificate Issuance and Tracking System (USDA-PCIT). 2024. https://pcit.aphis.usda.gov/PExD/faces/ViewPExD.jsf Accessed October 7, 2024.

Walters, D.S. 2011. Identification Tool to Weed Disseminules of California Central Valley Table Grape Production Areas. USDA APHIS PPQ CPHST Identification Technology Program, Fort Collins, CO. http://idtools.org/id/table_grape/weed-tool/  Accessed October 13, 2024.

Wiersema, J. H. and León, B. 1999. World Economic Plants: A Standard Reference. CRC Press, Boca Raton, FL, USA.

Author(s)

AUTEUR(S)

Deborah J. Lionakis Meyer, California Department of Food and Agriculture (retired)

Acknowledgment
The author wishes to thank the following from the Canadian Food Inspection Agency (CFIA): reviewer Jennifer Neudorf for her review and suggestions for fact sheet improvement. Thank you to Lyrae Willis for her images and image selection in the General Information and Additional Botany sections.

contactus@idseed.org

Last updated
on 2023-03-27

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