THE REST-PERIOD OF SEEDS 437 



Some of the works quoted in this chapter are — Goebel's 

 Organography of Plants ; Kerner's Natural History of Plants ; 

 Ewart's "Longevity of Seeds" {Proc. Roy. Soc. Victoria, 1908) ; 

 Ewart in Trans. Biol. Soc. Liverpool, 1896 ; Nobbe's Handbuch 

 der Samenkunde ; Schroder in Untersuch aus dem Botan. Inst, zu 

 Tubingen, BiLtid ii., 1886. 



SUMMARY 



(i) The rest-period represents a break in the continuity of the 

 young plant's life, and is the eftect of external conditions acting 

 through the parent and the fruit on the seed. The author's main 

 object in this chapter is to establish the inherent capacity of all 

 embryos to proceed uninterruptedly with their growth, whatever their 

 stage of developrhent when the resting state is imposed. 



(2) In dealing with this subject he discusses the prevalence of the 

 resting state in seeds, and the well-known circumstance just implied 

 that the rest-period has been imposed on seeds in all stages of develop- 

 ment of the embryo. 



(3) In the first case, he shows that this state of repose is often very ' 

 transient with a large number of plants, and that when we reflect 

 that many plants experience " after-ripening " in their seeds, when the 

 embryo continues to grow after the seed has entered the resting state, 

 the rest-period is deprived of some of its prominence as a feature in 

 plant-life (p. 418). 



(4) As concerning the second point, he directs attention to the 

 great importance of Goebel's observations on Anemone and Utricularia, 

 from which we learn that all the stages, from that of the unsegmented 

 acotyledonous embryo to that of the embryo producing its cotyledons 

 and even its first leaves, may be found not only in the resting seeds of 

 different individuals of the same species, but even in the same individual. 

 It is suggested that the problem thus confined within such narrow 

 limits presents an inviting field for further inquiry (p. 420). 



(5) The author points out that the inherent ability of the embryo 

 to continue its growth without the interruption of the rest-period is 

 itself implied in its existence in such varied stages of development in 

 the resting seed. The familiar after-ripening of seeds, above noticed, 

 and the well-known occasional germination on the plant of seeds 

 accustomed to submit to a normal rest-period, are also facts indicative 

 of this inherent capacity (p. 420). 



(6) Experimental proof is adduced to show that in the case of any 

 plant taken at random, such as Arenar'ia, Iris, Vicia, Quercus, etc., it is 



