210 Dr. Smith's Inquiry into the Structure of Seeds. 



it forms a separate organ. When the Embryo is accompanied 

 by a simple undivided organ or seed-lobe, we know it to be a 

 Cotyledon by its strict union, or even partial incorporation, with 

 the Embryo, as in Zamia*; whereas the pure separate Albumen 

 of the true Palms has, as in every other instance, no more con- 

 nection with the Embryo, according to Gsertner's just remark, 

 than is absolutely necessary ; and moreover evinces its true na- 

 ture by the chemical alteration, and speedy absorption, of its 

 whole substance. The Cotyledon, as I consider it, of Zamia, 

 as in numerous parallel instances, shrivels and shrinks indeed 

 considerably, from the absorption of its albuminous contents by 

 the vegetating Embryo, but does not disappear, leaving only a 

 skin behind, like the Albumen of grasses or corn, because that 

 part of its substance which is destined to perform the office, es- 

 sential to a Cotyledon, concerning air, merely decays when its 

 end is answered. It may further be observed upon this subject, 

 that the albuminous matter of seeds with two or more Cotyledons 

 is commonly of an oily nature, while those with one Cotyledon 

 or none at all, have a more farinaceous, or even stony, Albumen. 

 Still the latter changes to a milky or oily fluid, previous to its 

 absorption. When the vital principle of a seed is extinct, its 

 albuminous oil becomes rancid, and, even in seeds that retain 

 life, is liable to suffer some deterioration by keeping. Hence, 

 as Darwin observes, gardeners preserve Melon and Cucumber 

 seeds, perhaps for years, that the plants they produce may be 

 less luxuriant, in consequence of being starved at their first 

 germination; for any injury to the Cotyledons, even after they 



* Mr. R. Brown, who has observed the germination of a large species of Zamia in 

 New Holland, assures me that he found no such incorporation of the parts in question 

 as Goertner has represented in his t. 3, and that the structure and evolution of every 

 part bore an exact resemblance to Cycas as described by M. Aubert du Petit Thouars. 



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