254 MR. MIERS ON THE STRUCTURE OF THE SEED 
| raphe, is a development wholly unnoticed by Dr. Gray, by Endlicher, or by DeCandolle ; 
but it is an important feature, because it proves that the bony coating is the testa, and 
not the tegmen as has been inferred. 4th. The raphe proceeding from the hilum is wholly 
exterior to and free from the osseous coating, and interior to the outer tunic ; and this is 
the constant position of raphe, when it is free, in regard to arillus and ¢esta,—assuredly 
not in respect to testa and tegmen. 5th. As the raphe consists of the nourishing vessels 
originally existing in the funiculus or placentary attachment of the anatropal ovule, it 
could never have existed between the primine and secundine, but must have been, as Dr. 
Gray figures it, wholly exterior to the primine, and consequently, as we afterwards find 
it, outside the testa, which is the product of the primine; hence as the raphe is found in 
a free state, though partially impressed in its soft substance, within the external tunic, 
the inference is irresistible, that the latter must be of posterior growth, therefore arillus, 
and in this manner enclosing the raphe. 6th. We have thus the evidence complete, of 
the existence of the usual and distinct envelopes around the nucleus of the seed, viz. :— 
an inner integument with its apical chalaza, an intermediate hard testa with its corre- 
sponding diapyle, through which the nourishing vessels of the more exterior raphe pene- 
trate, and the whole included within a scarlet-coloured soft arillus. 
From all these facts we may safely infer, that the envelope, which is unquestionably an 
arillus in the Garciniee and the Tovomitee, must be of the same nature in the Clusiee, 
and that which is arillus in the Olusiee must be the same development in the Magno- . 
liaceæ : that which is granted in the one cannot be denied in the other. Although it be 
true that the several envelopes of the seed in different families are not to be recognized 
alone by their consistency, which may be, contrary to general rule, more or less membra- 
naceous, ligneous, cellular, or composed of oily or resinous granules according to circum- 
stances, yet they may be determined by their. relative position in regard to raphe, chalaza, 
diapyle, micropyle, hilum, &c., from which their true nature may always be inferred with 
greater certainty*. 
* The want of precaution in attending to the nature of the nourishing vessels proceeding from the placenta and 
penetrating the different integuments, in order to promote the growth and perfection of the seed, has frequently led 
to a misconception of its real structure. These vessels present themselves in the shape of a raphe-like cord under 
three very different aspects :—1st. When the cord, originating in the base of the cell, terminates often at the opposite 
extremity in the hilum of the contained seed; it is then properly the funicular cord, of which the common Cherry 
affords a very good example: sometimes it is inappreciably short ; in other cases, as in Magnolia, it forms a very long 
thread, by which the seed is suspended when it escapes from its cell. 2nd. When these vessels, existing in the form 
of a thread, either free and exterior to the testa, or partially imbedded in its substance, spring from the point of attach- 
ment of the hilum of the testa, and extending along its surface, penetrate its substance at a spot called the diapyle, to 
unite with the chalaza of the inner integument, which is invariably opposite to the cotyledonary end of the embryo ; 
this is the well-known raphe. 3rd. When the vessels passing from the hilum penetrate the inner integument and 
extend in the shape of a thread beneath its surface, in order to attain the radicular (not the cotyledonary ) extremity 
of the embryo; in this case they constitute the suspensor, which has sometimes been mistaken for a raphe; it 
occurs in Tropeolum, where its origin has been well illustrated and described by Dr. Giraud, in a memoir on the deve- 
lopment of the embryo in that genus, published in the nineteenth volume of the Society’s Transactions. The want of 
attention to the existence and position of the true raphe has often led to erroneous inferences in regard to the affinities 
of different genera, and among the Clusiacee may be cited the instance of Calophyllum. Gærtner (De Fruet. i. 200. 
tab. 43. fig. 1) gives an analysis of its fruit, where overlooking the existence of the raphe, he has mistaken the extra- 
