48 



LeguminoScB is endosperm ; its greater or smaller thickness 

 depends on the greater or smaller size of the emhryo. In the 

 whole family there is a very decided fluctuation in the pre- 

 sence and quantity of this albumen ; so that the suggestion 

 of Braun to distinguish the genera of Mimosese by it is quite 

 untenable. In fact there are some very good genera, as 

 Lupinus, in which some species have it and some have none. 

 Lupinus tomentosus and L. macrophyllus both have albumen, 

 L. tuberosus none. In Ononis altissima, it is scarcely to be 

 seen, whilst in O. aculeata it is very abundant, ^schyno- 

 mene fluminensis has a maximum, whilst 7E. podocarpa has 

 a minimum. Many more examples would undoubtedly occur 

 in large genera, as Trifolium, &c. In Acacia some species 

 have abundance, others none. But if the existence of albumen 

 fluctuates, much more do its relative quantity and its relative 

 position to the embryo. Its development is least decisive in 

 the whole family on the edges of the cotyledons ; in Papilio- 

 naceae least at the hilum and in greatest quantity between 

 the radicle and cotyledons, and in the commissure between 

 the cotyledons ; in both of which places it may be beautifully 

 seen in Scorpiurus sulcatus, yet it is sometimes wanting here 

 when it appears on the sides of the cotyledons. The quantity 

 of albumen has been supposed to be in an inverse proportion 

 to tbe size of the plumule, but this is not a rule even in the 

 genera, to which it was supposed to apply. Nor is a large 

 quantity of albumen accompanied with simple leaves of the 

 plumule, as was supposed by Braun. In opposition to the 

 oft-repeated assertion of Adanson, Jussieu, and DeCandoUe, 

 it is found that all the principal divisions of Leguminosae, 

 except Swartziese and Geoffrese, of which only one seed was 

 examined, possess albumen. 



3 b. Structure. — If a layer of albumen is cut, it is trans- 

 parent, almost of a horny consistence, becomes gelatinous in 

 water, is almost insipid to the taste, and consists of vegetable 

 jelly (P. pflanzengallerte of Schleiden) or mucus (P. pflan- 

 zenschleim of Berzelius). In most cases the colour is whitish, 

 in some beautifully white, as Cytisus, Kennedya, &c. When 

 it is transparent, so long as the testa remains on, it has a 

 variety of colours. In Bauhinia microphylla, the albumen 

 was of a wood-yellow colour. Where the albumen is tolerably 

 well developed, three layers are observed ; first, that next the 

 testa with resfular cells, well defined walls, and ordinarilv 



