Talk:Seed morphology

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Discussion for: Seed morphology • View • Links • Related changes

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Page scope

Seed morphology covers the outward characters of the Cannabis seed and how they are recorded: the fruit traits that separate wild-type from domesticated plants, size and weight across crop varieties and landraces, shape, colour and pattern and the scoring and measuring methods of plant-variety testing, germplasm collections and published studies. The structure and development of the fruit and achenes from burials are treated at Achene.

Data verification

Record source conflicts, figures that differ between studies and the limits of what each study tested. Keep narrative content on the article.

Discussion

Sources

Small (1975), Canadian Journal of Botany: fruit characters in the classification of Cannabis, the large, bare, blunt-based achenes of domesticated plants, the wider variation of uncultivated plants and the proposal that the wild syndrome measures departure from domestication.
Small and Cronquist (1976), Taxon: the wild and domesticated phases within each subspecies, told apart by an adaptive syndrome of fruit characteristics.
McPartland and Small (2020), PhytoKeys: Zinger's wild-type traits, the domestication syndrome, the key to the varieties of subsp. indica with its 3.6-millimetre threshold, perianth, venation and base, the exocarp colours of each variety, the large achenes of some Himalayan specimens, the limits of the key and the variation in their photographs between herbaria.
Naraine and colleagues (2020), Genetic Resources and Crop Evolution: length, weight, perianth adherence and basal attenuation of herbarium achenes of ruderal, fibre, oilseed and marijuana plants and the shorter, darker achenes of marijuana.
Manansala-Siazon and colleagues (2025), Plants: seed weight and size of 84 hemp accessions from 14 countries, the shape of the seed and its raphe, its colour, the loci for seed weight and volume, the maternal effect and the scanning and measuring methods.
Li and colleagues (2026), Journal of Pharmaceutical Analysis: length, width, thousand-seed weight and lightness of achenes from 20 Chinese landraces, their size and colour groups and the compounds that differ between dark and light hulls.
Gordon and Stansell (2026), The Plant Phenome Journal: seed size of 15 field-grown accessions grouped by origin and four counting and measuring methods compared.
Torne and colleagues (2025), BMC Plant Biology: the shape of 713 seeds of seven varieties by geometric morphometrics and the lower shape variation of self-pollinated feminised seed.
UPOV test guidelines TG/276/2 (2025): the three seed characteristics, their states and the stage at which they are observed.
The USDA hemp phenotyping and protocol handbook (version 4, 2025): seed weights and the scanned image of 20 seeds.
Bai and colleagues (2021), Journal of Ethnopharmacology: the mosaic on the exocarp of cultivated fruits.

Where the sources disagree

Where the pattern lies. Small (1975) writes of domesticated achenes that "usually lack an adhering, patterned perianth", and McPartland and Small describe the pigment of wild-type fruits in the perianth ("brown and mottled or marbled in appearance"). Bai and colleagues, citing Small (1975), write that the mosaic "is easily observed in cultivated strains because of the absence of the perianth over the fruit surface", placing it on the exocarp. The UPOV guidelines define marbling only as "the black mosaic pattern".
The size of the largest landrace achenes. Li and colleagues give the large-seeded group as 6.06 to 7.74 millimetres long in one section and 6.06 to 7.48 millimetres in another. Their morphological results give 3.96 to 7.74 millimetres for all 20 landraces.
The year of Naraine and colleagues. The paper was published online on 30 October 2019 and printed in volume 67 (2020).

How far the evidence goes

McPartland and Small's 3.6-millimetre threshold and their states for perianth, venation and base are for the varieties of subsp. indica in their classification. They describe plants from before recent hybridisation and say the key is not for identifying the "Sativa" and "Indica" strains sold today. They do not apply it to subsp. sativa.
Small (1975) found the achenes of uncultivated plants ranging from fruits closely resembling the domesticated kind to small wild-type ones.
The genes from domesticated plants in some Himalayan herbarium specimens are the authors' inference from the size and abscission mechanism of their achenes.
Naraine and colleagues express the darkness of marijuana achenes as "32 shades darker (on a 256-bit grayscale)"; a scale of 256 grey levels is meant.
The ranges for the 84 accessions are of accession means.
Gordon and Stansell compared 15 accessions, of which the East Asian ones had the largest and the United States feral ones the smallest seed; the grouping is by origin.
Torne and colleagues worked on cultivated varieties only. Their result concerns how the seed was produced (self-pollinated feminised seed against crosses), not wild against domesticated plants.
The UPOV guidelines score seed weight against example varieties and have no characteristic for seed length, width or shape.

Terms

Achene: the one-seeded fruit; the "seed" of cannabis.
Perianth: the thin covering left from the female flower, persistent in wild-type seed.
Abscission zone: the layer in the base where the seed parts from the plant.
Marbling: in the UPOV guidelines, the black mosaic pattern of the seed.
Raphe: the ridge that separates the width of the seed from its thickness.
Hundred-seed and thousand-seed weight: the mass of 100 or 1,000 seeds.
Geometric morphometrics: the comparison of shapes from the positions of fixed points (landmarks) and points along outlines (semilandmarks).

Images reserved in the article

One image has a place in the article but is not yet uploaded:

File:Cannabis-achene-wild-type-and-domesticated.jpg (Wild-type and domesticated seed), a drawing to be made: two achenes side by side over a 1 mm scale bar, the wild-type one labelled "Usually shorter than 3.6 mm", "Persistent perianth, mottled or striped" and "Protuberant base with abscission zone: falls when ripe", the domesticated one "Usually 3.6 mm or longer", "Perianth mostly shed; spots or stripes remain", "Veins of the exocarp visible" and "Blunt base: stays on the plant". No variety, place or seed seller named.