CHAP. II. 
ALBUMEN AND EMBRYO. 
249 
called the nucleus ; and consists either of albumen and embryo^ 
or of the latter only. 
The albumen [perispermium^ Juss. ; endospermium^ Rich. ; 
medulla seminis, Jungius ; secundince interncB^ Malpighi) 
(Plate VI. fig. 5. 1. 9. &c.), when present, is a body 
enclosing the embryo, and interposed between it and the in- 
teguments of the seed when there are any : it is of different 
degrees of hardness, varying from fleshy to bony, or even 
stony, as in some palms. It is in all cases destitute of vascu- 
larity, and has been usually considered as the amnios in an 
indurated state : but Brown is of opinion that it is formed by 
a deposition or secretion of granular matter in the cellules of 
the amnios, or in those of the nucleus itself. 
The former origin is certainly that of Santalum, Viscum, 
and Loranthus, as traced in the progress of its formation by 
Mr. Griffith; but it is deserving of enquiry whether bodies 
of very different natures and origins are not confounded 
under the common name of albumen. Has, for example, the 
albumen of Ranunculus, and other “albuminous” exogens, 
the same origin as that of Solanaceae, Scrophulariaceae, &c. ? 
The albumen is often absent, is frequently much smaller 
than the embryo, but is also occasionally of much greater 
size. This is particularly the case in monocotyledons, in 
some of which the embryo scarcely weighs a few grains, while 
the albumen weighs many ounces, as in the cocoa-nut. It is 
almost always solid, but in Anonacem and Myristicaceae it is 
perforated in every direction by dry cellular tissue, which 
appears to originate in the remains of the nucleus in which 
the albumen has been deposited : in this state it is said to be 
ruminated. 
The embryo (or corculum) (Plate VI. fig. 1. b, &c.) is a 
fleshy body occupying the interior of the seed, and consti- 
tuting the rudiment of a future plant. In most plants one 
embryo only is found in each seed. It nevertheless occurs, 
not unfrequently, that more than one is developed within a 
single testa, as occasionally in the Orange and the Hazel nut, 
and very commonly in Coniferae, Cycas, the Onion, and the 
Mistletoe. Now and then a union takes place of these 
embryos. 
