58 BOTANY. 
prolongations, in the form of lateral branches. Reproductive organs consist 
of spores, which are contained in mother-cells or perispores, or sporocarps. 
These are sometimes congregated together in receptacles of different sorts. 
The spores occasionally divide into three or four cells, constituting tetraspores. 
In addition te spores or sporocarps, there are sometimes round, or clavate, 
or filamentous cellular bodies present, to which some give the name of anthe- 
ridia. In some of the simplest Algze, the whole plant is concerned in 
producing new individuals by division of the parent cells imto two or 
four. In others there is a union of two filaments, and a passage of certain 
granular particles (endochrome) from the one to the other, ending in the 
formation of the spore. This process is termed conjugation, and is one of 
great interest. It has been observed in some of the Confervacee and 
Diatomacee. In certain cases, the terminal cell of the filament is that in 
which a spore is formed without any conjugation, and in these cases the 
spore is frequently provided with ciliary processes, which exhibit for a time 
spontaneous movements; hence called zoospores. In the higher Algz, the 
sporocarps containing two, four, or more reproductive cellules, are united 
together in conceptacles along with filaments containing phytozoa, and 
called antheridia. In Characee there are two distinct organs of re- 
production. 
Sub-order 1. Diatomacee: inhabiting still waters and moist places ; 
fronds consisting of frustula or fragments, which are either angular or 
cylindrical, often silicious and brittle (non-silicious in Desmidiez) united 
by a gelatinous sort of substance; propagated by the division of parent 
cells into two halves, which become more or less completely detached, and 
form new individuals. Conjugation also takes place in some instances, in the 
same way as in the Confervacee. 
Sub-order 2. Confervacee: aquatic plants often of a green color, con- 
sisting of one or more cells of a rounded or cylindrical form, united together 
So as to form an articulated or flat frond. They increase by the merismatic 
division of cells. Reproduction effected by spores which are formed in the 
interior of the cells by a change in the arrangement of the granular matter, 
or by the union of filaments of different plants, a process of conjugation by 
which granular matter passes from one to the other. Pl. 54, fig. 34, a-d; a, 
Conferva bombycina ; 6, C. rivularis in various states: c, C. flaccida and d, C. 
glomerata. 
Sub-order 3. Floridee, or Ceramiacee : rose or purple-colored sea-weeds, 
with fronds formed of a single row of articulated cells, or of several rows of 
cells combined into a flat expansion; organs of reproduction consist of sporo- 
carps or perispores, intermixed with clavate filaments called antheridia. The 
sporocarps contain cells or spores often divided into four (tetraspores), and 
inclosed in conceptacles of various kinds. 
Sub-order 4. Fucacee, or sea-weeds, the sea-wrack tribe: usually growing 
in salt water: frond consisting of cells which are often united by gelatinous 
matter, and which sometimes form a broad expansion (a membranous 
thallus), supported on a stalk; organs of reproduction consist of sporocarps 
and antheridia, contained in conceptacles opening externally, which are 
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