STUDIEvS IN RETARDED GERMINATION* 



AnSTKACT 15V Iv C. ROGKRS 



Dr. Puchner informally classifies seeds as to promptness of germina- 

 tion into tiiese classes : 



1. Seeds which are at once capable of germination as soon as they 

 reach maturity on the mother plant as aspen, elm. Such seeds must 

 be sown at once after ripening, before their vitality disappears. 



2. Seeds which may germinate also very quickly after ripening but 

 not so promptly as in Class 1. These obtain their vitality for a longer 

 period, e.g.. the most of the cereals, radishes, the Brassicae, and the 

 "Kleeartigen Gruachse." According to many observations ^ it appears 

 "useful" not to sow many of these seeds immediately after the harvest. 

 They germinate better when a certain period of storage precedes the 

 sowing. With such seeds the conditions of "Schnittreife" and ''Keim- 

 ungsreife'' do not completely coincide. 



3. Seeds of many trees and flowers, in whicli "Schnittreife"' and 

 "Keimungsreife" are separated in a pronounced manner by a longer 

 or shorter so-called "Samenruhe" or "Keimruhe." This last class 

 is again divided by the author into: (a) Seeds which, although capable 

 of quick germination, are held back by the development or formation 

 of the seed coat ("Hartschaligkeit"), e.g., many of the Papilionace?e. 

 With these seeds not all individuals are thus delayed, only a limited 

 number of them. (7^) Seeds in which the delay is not confined to 

 certain individuals but which is the rule. Impermeability of the seed 

 coat does not apply here, e.g., yew, ash, cherry, hawthorn, the Pomaceae 

 in general, many palms among the trees and Primula, Oenothera. 

 Canna, Polyanthus, \^iola. Phlox, Gentian, Verbena, and most of the 

 monocotyledonous plants among the flowers. 



Dr. Puchner mentions as an example of "Hartschaligkeit" vicia 

 villosa or sandvetch and discusses it briefly, attributing -its delayed 

 germination to the position and character, of the palisade cells of the 



*Untersuchungcn iiber vcrzogcrte Keimung. (N'aturwissen schaftliche Zeit- 

 schrift fiir Forst und Landwirtschaft). (13:159-178. Apr.-May, 1915.) By 

 Prof. Dr. Puchner of the Kgl. Bayer, Saatsuchtanstahl im Weihenstephan. 



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