FLINTSmilE PLANTS NOT RECORDF-D IN ED. 2 <)!<' ' TOP. BOT.' 357 



epidermal, cortical, and medullary or central, though the aspect of 

 these is not quite the same as the tissues so named in other forms. 

 In the stipes the epidermal tissue consists of several layers of small 

 cells, placed in rows vertically to the surface. The cortex is un- 

 usually thick, and is formed of cellular elements with greatly 

 thickened walls, while the medullary tissue is reduced to a thin 

 central band. The lamina presents the same series of tissues, but 

 the epidermal layers are not so numerous. In both portions the 

 central tissue is made up of branched filamentous structures, which 

 run longitudinally, closely interwoven with others of a more 

 fibrous character, which, for a part of their course at least, run 

 transversely. 



To observe the phenomena of continuity presented by sections 

 of these tissues recourse must be had to the most effective reagents 

 for swelling, clarifying, and even partially dissolving the strongly- 

 thickened walls of the histological elements. In sections success- 

 fully treated with these ends in view, it is not difficult to make out 

 an elaborate system of connections between the protoplasts, both 

 in the central and the cortical tissue. The type of continuity here 

 presented is chiefly, if not exclusively, that which is maintained 

 through the intervention of a sieve -plate. The protoplastic con- 

 tents of the central structures are for the most part reduced to 

 comparatively small threads, but at the transverse partitions they 

 dilate to the full breadth of the plate. In some cases the whole 

 plate is traversed by the connecting threads, but in others the 

 connections appear to be altogether peripheral. 



The protoplasts of the cortex are rhizopod-like masses, with 

 pseudopodia spreading in such a manner that the cells of each 

 layer are brought into connection both with one another and with 

 those of adjacent layers. As in the centre, continuity is effected 

 through the intervention of sieve-plates, the whole or merely the 

 periphery of which may be traversed by the protoplasmic threads. 



As in the case of Rimanthalia lurea, the presence of continuity 

 in the epidermal tissue is still doubtful, though a^Dpearances are 

 suggestive of it. The fact remains, nevertheless, that in spite of 

 many efforts to make a suspicion a certainty, a demonstrative case 

 has not yet been met with. 



FLINTSHIRE PLANTS NOT KECOEDED IN ED. 2 

 OF 'TOPOGRAPHICAL BOTANY.' 



By Kobert Brown. 



Although the county of Flintshire in North Wales is of small 

 extent, the Flora is varied and extensive. Including the estuary of 

 the River Dee, it possesses a considerable amount of sea-coast, and 

 its geological features are of much interest. Limestone is often 

 present, so many plants are found peculiar to this formation. 



