26 FRUCTIFICATION, OR FLOWER AND FRUIT. 



food of the germinating Embryo. Gaertner 

 distinguishes an organ by the name of Vitellus, 

 or Yolk, in Seeds, which appears to me always 

 either a pair of subterraneous Cotyledons, or a 

 part of the Embryo ; see Trans, of Linn. Soc. 

 v. ix. 204. 



4. Testa, the Skin, either simple, or lined with a 

 finer film, Membrana, contains, and gives a 

 shape to, the foregoing parts, and in vegetation 

 bursts irregularly. A pulpy Seed, Semen bac- 

 catum, is furnished with pulp between the Mem- 

 brana and the outer Skin, as in Jasminum*. 



5. Hilum, the Scar, or point of attachment, at the 

 base of every Seed, where all the internal parts 

 meet, and through which they are nourished 

 while growing. 



Accessory, not essential, parts of a Seed are : 



o. Strophiolum, the Crest, an occasional appen- 

 dage to the Scar, of a glandular appearance, as 

 in Chelidonium, and some Leguminous genera, 

 Ulex, Spartium, <8$c. 

 7. Pellicula, the Pellicle, a thin close membrane ; 

 a downy covering ; or a glutinous substance, 



* M. Richard, who unnecessarily, I think, invents the term Epi- 

 sperm for the Testa of Gaertner, asserts this covering to be always sim- 

 ple, though he allows it to be formed of two membranes, with an in- 

 termediate vascular parenchyma, or pulp. Any person who examines 

 the kernel of an Apple will surely, in every stage of its growth, find a 

 double Testa, the outermost firmly coriaceous, the innermost mem- 

 branous; nor are numerous instances, of the same kind, wanting^ 

 where, the external Testa can by no means be taken for any thing else. 



