PROGRESSIVE STAGES IN COMPLEXITV OF STRUCTURE. 580 



in the pools where these species grow huudreds and thousands of separate nets are 

 to be found living together within a limited area. But the number of instances 

 of swarm-forming cell-complexes is, however, utterly insignificant in comparison 

 with the enormous number of those forms in which the tissues arising by re- 

 juvenescence remain connected. We call these permanently-connected cell-tissues 

 systems; and distinguish between systems of cell-rows, cell-nets, cell-plates, and 

 cell-masses. The ai-rangement of the individual parts, and the fitting together 

 of the systems is quite irregular, but is defined for each plant-species in the 

 established manner, inherited from generation to generation. The simple cell- 

 tissues which build up an extensive system can be distinguished as separate parts, 

 and may be compared to the members of a body, and even called members of that 

 system. There are, of course, sj^stems which consist of very many simple cell- 

 tissues, and therefore have a much-membered appearance; and others which exhibit 

 only a slight organization, i.e. are built up of only a few simple tissues. Setting 

 aside the question of greater or smaller, the kind and manner of connection must 

 be taken into consideration in a general review of the forms of plants, and these 

 systems can be comprehended under two divisions. 



The first division comprises those whose members (i.e. cell-complexes) are all 

 of similar shape, so that the whole plant-body consists only either of cell-filaments, 

 or of cell-nets, or of cell-plates, or, finally, of cell-masses. These uniform sj'stems 

 are found more especially in plants growing under water, which reproduce them- 

 selves by spores, as well as in fungi, and the commonest forms to be noticed are as 

 follows: — fii'st, the clusters of tortuously twisted and intertwined rows of cells, like 

 sti'ings of pearls, such as occur in the Nostocacea?, the bundles of elongated. 



■'S" 



straight filamentous rows of the OscillatorietB, the flock-like Scytonema and 

 other aquatic plants, and the dark cushions of whip-like rows grouped in bundles, 

 as shown in the genera Euactis and Dasyactis. Among the series of complex 

 systems a particular interest is claimed by those which are produced from the 

 frequently-mentioned hyphse. When the branched hyphse, often knitted into 

 meshes, and united into net-works, are crowded together in great numbers, plexuses 

 and strands arise which have exactly the appearance of a cell-mass, but which 

 may be distinguished therefi-om by the fact that neighbouring cells, whose sides 

 adjoin one another, are not produced by the intercalation of partition-walls. The 

 fungal hyphae have a common development and manner of growth ; hundreds of 

 hyphal threads which are joined together into a strand or plexus continue to grow 

 at the apices with equal rapidity and in the same direction; they carry out in com- 

 mon the same curves and twistings, often divide into single threads, then i-eunite, 

 ami thus form the most peculiar shapes. The so-called Hercules-club (Coryne 

 pistiU(iris), the strange forms of Glavaria, resembling pieces of coral, the Cap-fungi, 

 divided into cap and stalk, the Helvellas and Morels, the very peculiar puff-balls 

 and earth-stars, and many other forms are built up of hyphal strands and plexuses, 

 which, as already stated, are nothing else but conglomerated cell-nets. Systems of 

 cell-plates are more rarely to be met with. Thi.s construction is found most 



