92 The Genera and Species of 



the cotyledons were incumbent. I have carefully examined our 

 common species of this genus, which is generally regarded as 

 hardly a variety of C. muritima, but I find the cotyledons con- 

 stantly accumbent. Once, indeed, I saw the lower seed with 

 incumbent cotyledons, while in the upper they were in the or- 

 dinary state. In another instance they were incumbent in the 

 inferior seed, and spirally twisted on the axis of the silicle in 

 the inferior. In our common Arabis lyrala* the cotyledons 

 are obliquely incumbent, the radicle lying close by the edge. 



De Candolle states in his Mem. stir les Crucif., that of 970 

 species of this family, described in his Systema, he had dissected 

 the fruits and seeds of more than 700, and yet he noticed 

 scarcely any anomalies. He, however, overlooked the in- 

 cumbent cotyledons of Arabis Thaliana, Linn., which Sir W. 

 Hooker, following Gay,t has very properly removed to Sisym- 

 brium, as the radicle is truly dorsal. 



Some valuable observations on the embryo of Cruciferae, by 

 MM. Monard and Gay, are recorded in the seventh volume 

 of the Annates des Sciences Naturelles.J They give an account 

 of seventeen species which deviate from the character of the 

 suborder to which they were referred in the Systema. Some of 

 these were corrected by De Candolle himself in the Prodro- 

 mus, while others were merely placed in wrong genera. 

 About half the plants noticed by these botanists are examples of 

 accumbent and incumbent species existing in the same genus. 

 Dr. Brown (in PL of Oudney, p. 6,) thinks that in dividing 

 Crucifene into natural sections, we are not to expect absolute 

 uniformity in the state of the cotyledons ; at least in the accum- 

 hent and flatly incumbent states. This learned botanist does 

 not, however, inform us to what extent he is at present disposed 



* The tubuli of the dissepiment in this species are like those of A. Canadensis. 



t Ann. Sc. Nal. 7, p. 399. 



X Observations sur quelques Cruciferes decretes par M. De Candolle dans le 

 second volume de son Syst. Nat. Reg. Veg.—Par I. P. Monard, avec de« notes 

 de M. Gay Ann. des Sc. Nat. 7, pp. 389-419, (1826.) 



