aert , ke 
5 ak Pa > oS 
7 
2h he External Form of Plants. gaa 
forms the substance known in commerce as mace: in 
the yew (Fig. 328), it forms a drupaceous pseudo-berry.' 
Appendages of other kinds to the seed occur in the form 
—— == WAY & 
Fic. 329.—Winged seed of Bignonia Catalpa. 
of wings, as in Bignoniaceze (Fig. 329), and Coniferee (Fig. 
304, p. 147), [in the latter case the wing does not belong 
to the testa, but to the woody 
scale to which the seed is at- 
tached], or hairs, as in Pole- 
moniaceze, &c. (Fig. 330). 
The seed consists of an 
integument anda nucleus, the 
first being formed from the 
integuments, the last from the 
nucleus of the ovule. 
The zntecument consists Fic 330.—Ripe seed of Epz/obium, with 
5 f coronet of hairs (magnified). 
of an outer and an inner layer, 
‘the former being sometimes called the esta, and the latter 
the fegmen. In the walnut the outer layer is yellow and 
Fic. 331.— FIG. 332.—Re- Fic. 333.— Spiny seed of Stel/arza, entire and 
Smocth seed ticulated seed cut through, both lengthwise and trans- 
of Aguilegia of __— poppy versely, showing the campylotropous form, 
(magnified). (magnified). the curved embryo: surrcunding a copious 
endosperm (maguified). 
_ 1 [The tern aril is, strictly speaking, confined to a structure of this 
kind which springs from the hilum, as in Passiflora, Taxus, Vymiphea, 
&c. A similar structure, originating at or near the micropyle, as in 
Euonymus, Euphorbia, Polygala, &c., is a false aril or arillode ; if from 
the testa, independent of the micropyle or funicle, as in Cheledonzune, 
Viola, &c., a strophiole or caruncle.—ED. | 
