Parsons : Flowerless Plants and their Habitats. 37 



guished from fungi. In algte the tLallus, or vegetative part, forms 

 the greater part of the plant, the fructification being inconspicuous, 

 and in some kinds rarely met with ; in fungi the fructification is 

 usually the most conspicuous part of the plant. Algae consist 

 entirely of cells, sometimes embedded in a mass of jelly. In the 

 simplest forms each cell constitutes a distinct plant, in others the cells 

 are placed end to end in one or many rows, forming long threads, 

 and in many seaweeds they form flat expanded leaflike fronds. One 

 order — the diatoms — is remarkable for the cell wall being of flint, and 

 exquisitely sculptured with lines and markings of wonderful diversity. 

 Many of the lower algae possess astonishing powers of locomotion : 

 thus the unattached Diatoms swim with a darting movement, Oscilla- 

 toria by slow side-to-side undulations ; Vibrio by rapid wriggling ; 

 Yolvox and its allies, by means of cilia. 



The fructification of algae is very varied ; we often find several 

 different kinds in the same species. The principal forms met with 

 are, antheridia containing moving, fertilizing particles ; spores con- 

 tained in definite spore cases ; resting spores formed from the cell 

 contents after fertilization ; tetraspores, cells containing spore-like 

 bodies in clusters of four ; and zoospores, green bodies formed with- 

 out impregnation from the contents of the ordinary vegetative cells, 

 swimming actively by means of cilia, and which have even been said 

 to possess an eye to guide their movements by. 



In some of the green algee we find the process of fertilization 

 reduced to its simplest 230ssible form — two exactly similar cells, lying 

 side by side, become connected by a transverse tube like the letter H. 

 The green cell contents are all collected either into one of the cells 

 or into the transverse tube, forming a round mass, which ultimately 

 breaks up into spores. 



There is yet one other order of Cryptogamia — the Characete — which 

 I should probably have forgotten had I not been reminded of it by 

 finding an interesting example on Saturday. I cannot be said, how- 

 ever, to have missed it out of the proper sequence, for these plants 

 are so utterly unlike all others that it is not known what their proper 

 place is ; they are sometimes placed after the vascular acrogens, at 

 others next the algse, but in either case simply as a matter of con- 

 venience. Like Equisetacse, Characea^ is a small order consisting of 

 but a single genus, Chara — of world-wide distribution and of great 

 antiquity, being at least as old as the lias. Charas are leafless water 

 plants with a thread-like stem, and whorls of branches bearing 

 branchlets \ they have an unpleasant odour, and are generally 



