252 PHYSIOLOGICAL BOTANY. 



tenuta in Milano/ Milan, 1845, vol. iv, p. 511 ; more in 

 detail in the ' Flora/ 1845, p. 272 ; also in rny ' Lectures 

 on Botany/ part ii, Berlin, 1845, p. 309. The Date- 

 palm is the subject there treated of. In germination, 

 the embryo or the cotyledon becomes elongated, as is 

 usual in the Monocotyledons, and splits into a sheath, 

 from the base of which the stem grows upwards and the 

 root downwards. The former, which is surrounded by 

 the sheath, contains within it a small tuberous body, 

 consisting of parenchyma and delicate spiral vessels 

 passing round it; above, it immediately forms a bud, 

 consisting of leaves only, as in the Monocotyledons 

 generally. The leaves acquire considerable length, whilst 

 the stem remains as an almost spherical tube. If it be 

 examined at the end of several years, about six or eight, 

 its section exhibits a nucleus, which is throughout tra- 

 versed by a plexus of vascular bundles, which interlace 

 in every direction. The nucleus is surrounded by a 

 cortex of parenchyma; at the upper part, beneath the 

 bud, there is also a layer of parenchyma forming a cortex, 

 through which vascular bundles pass from the nucleus to 

 the leaves. Thus the young Palm perfectly resembles a 

 corm, which only differs from a true bulb in the absence 

 of the fleshy scales. On making a section of the tall 

 part of the stem of a Date-palm, we find a number of 

 vascular bundles traversing it longitudinally. The nearer 

 they are to the circumference, the closer they are toge- 

 ther; and at the very circumference they are most 

 closely crowded, whilst towards the centre they are more 

 scattered, more surrounded with cellular tissue, and they 

 are most scattered at the very centre. On closely examining 

 the woody bundles, we find that they are by no means 

 parallel to each other, but interlace in various ways, 

 forming, however, but very small angles with each other. 

 Hence the stern of a Palm is a longitudinally extended 

 corm. 



Neither Mirbel nor Gaudichaud have noticed this bulb- 

 like condition of the young Palm-stem, nor have they 



