32 



DOMESTIC BOTANY. 



young shoots of willow, poplar, or any free growing 

 stem. This applies to net-veined leaved plants only. It 

 is, however, difficult to reconcile opposite or verticillated 

 with this view, but careful examination shows that in 

 some cases their bases are not in the same plane of at- 

 tachment. In Sempervivum (house-leek), the leaves 

 are so compact and imbricate over each other, that in 

 S. sahulare they form a round flat disk ; in Scalyciforme 

 they are curved inwards, forming a cup. The term 

 rosette is applied to plants of this nature, with which is 

 included Saxifraga 'pyramidalis and its allies ; all leaves 

 rising direct from the root- stock bud are called radical. 

 Leaves are amplexicaul (stem clasping), when the bases 

 surround the stem, and when such is the case in opposite 

 leaves, they are called connate, as in teazles. In Crassula 

 perforata its opposite leaves are so united together, that 

 by a little pressure with the fingers, they can be made to 

 revolve round the stem. It has been stated that succulent 

 stemmed plants, as cactse, are destitute of leaves, and this 

 is not uncommon in many other plants, as furze, the 

 thorns of which may be considered in place of leaves; 

 true leaves being only occasionally seen. But the most 

 special example of leafless plants is found in a great 

 number of Australian species of Acacia, consisting of 

 trees and shrubs of very diff'erent habits, apparently 

 clothed with leaves, varying from needle-like to the 

 breadth of one, two, or three inches, and from four, 

 six, eight, or more inches in length, having a midrib 

 and veins ; they are, however, not true leaves, but leaf- 

 stalks (petioles) only, as is evident on examining the 

 base of connexion, their margins being vertical, and not 

 in the ordinary horizontal position of leaves. These 

 are called phyllodce ; but that they are only leafstalks 



