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Luzula .spicata L. seeds are completely dormant at maturity. A germination inhibitor is present at the micropylar end. Normally, the only effective means of eliciting germination is a precise scarification of the micropylar end which inactivates the inhibitor. Exogenous application of gibberellic acid, kinetin, KNOy, and thiourea have no affect on the dormancy of unscarified seeds. Scarification of the hilar end of the seed does not elicit germination, but when gibberellic acid is applied to the hilar scarified seeds moderate germination results. Presumably, these seeds are dormant due to a deficit of endogenous gibberellin; a condition which can be overcome by the application of gibberellic acid to seeds scarified at a site in itself ineffective in producing germination. Apparently the gibberellic acid serves to initiate amylase activity in the endosperm, overcoming the inhibitor block. Luzula spicata seed dormancy is apparently unique in that a germination inhibitor is operative in conjunction with the commonly recognized gibberellin-amylase mechanism.

The nature of achene dormancy was studied in two species of alpine sedges, Carex albonigra and C. ebenea, from the Rollins Pass area of the Colorado Front Range. Germination response of achenes was determined under various treatments, including stratification, scarification, leaching, extraction, exposure to light, and application of various plant growth regulators. Two distinctly different requirements for seed germination are exhibited by the two species. In C. albonigra, only scarification at the basal end of the achenes resulted in germination. Only fluorescent and red light were effective in promoting germination in C. ebenea achenes, suggesting a reversible photoreaction as the mechanism responsible for dormancy in this species. The light effect was apparently cumulative, with a minimum of about 15 days of continuous light being required for the initiation of germination.

Summary Distichlis spicata, a salt marsh grass, sets dormant seeds which exhibit a low‐temperature, after‐ripening requirement. In addition to stratification, localized scarification and nitrate are effective agents in breaking dormancy and promoting seed germination. The pericarp and/or testa are impermeable to organic plant‐growth regulators, but not to water or inorganic salts. Gibberellic acid and kinetin are ineffective in breaking dormancy and do not affect germination. Abscisic acid, however, effectively inhibits stratified and scarified seeds. Dormancy and germination appear to be hormonally controlled. It is suggested that the endogenous inhibitor constitutes a block to nitrate reductase activity in the endosperm. Presumably the inhibitor blocks specific DNA transcription sites in the aleurone cells, but can be overcome by after‐ripening (inhibitor decay), abrasion (inhibitor leaching) or nitrate induction.