380 On Sclerenchyinatotis Cells. [Sess. 



much Turauched kinds occur in lacunar tissue, known as 

 spongy parenchyma, from its loose texture — their branches, 

 Hke so many horns, being pushed into the cellular interstices. 

 According to the best authorities, their main purpose is that 

 of imparting strength and rigidity to the tissue in which they 

 lie, from their evident power of binding it together, and in 

 many instances giving also great elasticity. In the long, slender, 

 yet very elastic and firm flowering-scapes of rushes (Juncus, 

 Scirpus, &c.), and in plants not properly forming wood other- 

 wise, lignified sclerenchymatous strands either run close be- 

 neath the epidermis, or a closed ring of that tissue lies near the 

 periphery, and gives the thin column the necessary rigidity, 

 at the same time imparting that wonderful elasticity which 

 enables such plants, on being almost bent into a semicircle by 

 wind-pressure, to recover themselves. In the Nymphseacese 

 they project like many-branched stellate hairs into the wide 

 intercellular spaces. They are stellate-branched in the leaves 

 of the vimbrella pine (Sciadopitys) and the araucaria. They 

 are well seen as dark-brown bands in transverse sections of 

 the common bracken. In the leaves of the Kaurie pine they 

 look in many instances like the antlers of a stag. One point 

 is observable between these cells in the Kaurie pine leaf and 

 those in ISTymphtiea — viz., that in the former the branches 

 spring from the body of the cell at any point, whereas in the 

 latter there are only three poles or points from which they 

 spring. In the former they are much more numerous, and 

 obviously from their shape, or rather want of shape, bind the 

 tissue elements together in which they lie. In the latter, 

 whatever may be their purpose, they do not look like support- 

 ing elements. They have been thought to have in this case 

 an excretory function, being studded with numerous small 

 particles of calcium oxalate, which, from its physiological sig- 

 nificance, is a metabolic product, and no longer of use in the 

 economy of the plant. 



In the willow-leaved Hakea {H. saligna) there is on both 

 the upper and under surfaces of the leaf, and lying immedi- 

 ately under the epidermis, a regular network of thick-walled 

 cells. In transverse section, however, it is seen that this net- 

 work results from the entwining of the long arms or prolon- 

 gations of erect, oblong, rod-like, very thick-walled cells, dis- 



