SIR J. LUBBOCK—PHYTOBIOLOGICAL OBSERVATIONS. 77 
fruit. The embryo again is slightly bent, following the direction 
of the seed. Consequently the one cotyledon occupies the inner, 
the other the outer side of the curve; and, as shown in fig. 160, 
the outer one is distinctly larger than the other. 
The Hemp (Cannabis) and Caylusea present us with other cases 
more or less resembling that of Hesperis mentioned in my previous 
memoir. 
In Thunbergia reticulata the cotyledons are unequal, ovate, 
obtuse, slightly emarginate, and cordate at the base. The 
larger one is slightly denticulated, and with a curious embossed 
patch in the centre; the smaller one is, on the contrary, smooth 
and entire, or nearly so. The seed is orbicular or oblong ; aperi- 
spermic, 3—4 millim. in diameter, compressed, with a cavity on the 
Fig. 160. 
` Coreopsis Atkinsoniana. Seedling. X 10. 
inner side. The embryo is slightly curved ; and the cotyledons 
lie with their faces towards the hilum, which is very prominent; 
the inner cotyledon is turned up at the edges, and wraps, to a 
certain extent, rouud the outer one. The raised or embossed 
patch in the centre of this cotyledon is due to the inward curva- 
ture of the testa. 
Position of the Embryo in the Seed. 
Plantago. 
As a general rule, the arrangement and position of the embryo 
in the seed is approximately the same within the limits of any 
one genus. There are, however, many exceptions. In the genus 
Plantago, for instance, the cotyledons sometimes have their faces 
and sometimes their edges to the placenta. This difference is 
not indeed mentioned either by Barnéoud or Decaisne in their 
respective monographs. of the family. Bentham and Hooker, 
LINN. JOURN.—BOTANY, VOL. XXIV. H 
FICTIS ne rn 
