102 The Ottawa Naturalist. . [August 



lenticular with pointed end. Generally highly glazed. 

 Gramineae. (Grass Family). 



Grain or caryopsis has small embryo placed at the base 

 of the grain. Wheat grain is typical of the grain of manv 

 genera with palets removed. Some genera have highly glazed 

 palets closely adhering to the caryopsis. 



From the above it will be seen that the seeds of some families 

 at least have certain characters peculiar to them which aid 

 materially in their identification. 



The identification of the species is a much more difficult 

 matter and generally speaking requires long experience in order 

 to become at all proficient in this connection. In the species of 

 the genus Brassica for instance, it was pointed out that it is neces- 

 sary to plant the seed of dotibtful samples and produce the first 

 foliage leaves at legist in order to be sure of their identity. 

 Within recent years that part of the study of botany which has 

 to do with the seed has been largelv overlooked although a most 

 interesting field of work is offered in this connection. 



Mr. G. H. Clark next presented the following paper: — 



Conditions Unfavorable to the Resumption of Growth 

 BY THE Dormant Embryo in Seeds. 



True germination in seed producing plants takes place 

 when the oospore germinates after fertilization within the 

 ovule has been secured, which process of fertilization produces 

 the oospore. The succeeding generation then commences in 

 the development of the embryo, which, when ready to separate 

 itself from the mother plant, is surrounded by, attached to, or 

 contains within its cells a supply of nutriment necessary to its 

 further growth. The seed is then said to be ripe, and the 

 embryo plant ma}' then be said to be ready to enter upon a 

 period of rest. It is well known that with many kinds of seeds 

 a rest period is enforced, which mav be taken as one 

 of nature's methods of providing for the perpetration of the 

 species. Experiments conducted in the seed laboratory with 

 many kinds of cultivated plants and with weed seeds make clear 

 that this preservation of life, or delayed germination, varies 

 considerablv, even with fully ripened seeds taken from the same 

 plant. 



Conditions that arc unfavorable to germination. 



(a). Maturity of embryo. Although the seed may be said 

 to be ripe when it has naturally separated itself from the mother 

 plant, the embryo is not necessarily fully matured in the ap- 

 parently ripe seed until such time as it may be able to commence 

 with the process of secreting enzymes, which are necessary to 

 the digestion of the food stored bv it for the purpose of its nutri- 



