Kinds of seed: Buckwheat, rhubarb, and sorrel.
(a) General description.
(1) Germination habit: Epigeal dicot.
(2) Food reserves: Cotyledons, starchy endosperm.
(3) Shoot system: The hypocotyl elongates carrying the cotyledons above the soil surface. The epicotyl usually does not show any development within the test period.
(4) Root system: A primary root, with secondary roots developing within the test period for some kinds.
(b) Abnormal seedling description.
(1) Cotyledons:
(i) Less than half of the original cotyledon tissue remaining attached.
(ii) Less than half of the original cotyledon tissue free of necrosis or decay.
(2) Epicotyl:
(i) Missing. (May be assumed to be present if cotyledons are intact.)
(ii) [Reserved]
(3) Hypocotyl:
(i) Deep open cracks or grainy lesions extending into the conducting tissue.
(ii) Malformed, such as markedly shortened, curled, or thickened.
(iii) Watery.
(4) Root:
(i) None.
(ii) Weak, stubby, or missing primary root with weak secondary or adventitious roots.
(5) Seedling:
(i) One or more essential structures impaired as a result of decay from primary infection.
(ii) Albino.
[59 FR 64506, Dec. 14, 1994]