THE VICTORIAN NATURALIST. 89 



The Macrocystis pyrifera is certainly the highest plant in 

 the world, for Harvey says it has been estimated at from 500 

 to 1,200 feet long, but he thinks an average of these, say 800 feet, 

 would be correct. As the stem increases new leaves are con- 

 stantly formed at the apex, the old leaves never being renewed, 

 so that in time it becomes a huge brown vegetable rope crowned 

 by leaves. The leaves are lacerated in a peculiar manner. At first 

 the terminal leaf is very broad and splits up into ribbons, com- 

 mencing near the edge furthest from the stem ; these ribbon-like 

 leaves form long petioles, which swell out into air bladders and 

 thus support the plant. 



The reproduction of this enormous vegetable is effected in the 

 very simplest manner. At its base, on the rock, a few small radical 

 leaves make their appearance. On these may be observed small 

 cloud-like patches. These, when viewed under a good lense, turn 

 out to be ovoid transparent spores closely packed with hairs, both 

 interspersed amongst them and completely surrounding them. No 

 reproductive organs have been observed on the main plant, so 

 that the longest vegetable in the world comes from a spore that 

 can barely be distinguished by the naked eye Other large plants 

 which may be seen are Cystophora. These are anchored to the 

 bottom, waving their great arms abroad and lashing themselves to 

 ribbons against the rocks. 



If the larger seaweeds be carefully examined immense numbers 

 of diatoms may be found adhering to them. 



These microscopic plants are unicellular, and are completely 

 covered by beautifully marked . frustules, as they are termed. 

 Frustules are formed of silica, and are really complete shell-;, each 

 plant having two shells, the edge of one shell fitting over the 

 other in the same manner that a lid fits over a box. Where the two 

 edges overlap is termed the girdle. The chlorophyll in diatoms 

 is completely masked by a matter called diatomen, which changes 

 it into a rich brown colour. The mode of reproduction is peculiar. 

 Each half of the plant separates slightly from the other and each 

 produces a bud. These buds grow until each is equal in size to the 

 half that produced it. One old half and a bud then separates from 

 the rest, and thus we have two new plants from one old one. 

 Amongst the brown seaweeds we find a near approach to the 

 structure of land plants. Most other Alga? are formed from the 

 simple cell, either as unicellular, cell filaments, cell plates, or cell 

 masses, but in Fucus and allied plants, although there are no 

 actual vascular bundles, still there is a difference of tissue, the 

 central cells being elongated and loose, whilst the outer ones are 

 close and short. Here, also, we see the nearest approach, in 

 appearance at any rate, to roots, stems, and leaves, these organs 

 being entirely wanting in seaweeds. 



But it is the morning after a storm that the seaweed collector has 



