764 ALG A. 
branches (fig. 856, s, «), and either on the same or on different 
branches of the same plant, or on separate plants. These 
organs are termed globules or antheridia (figs. 856, a, and 858) 
and nucules or carpogonia (figs. 856, s, 859, and 860). (See 
pages 390-392 for a detailed account of their structure.) 
Distribution and Nwmbers.—These plants occur in stagnant 
fresh or salt water in all parts of the globe; but they are most 
abundant in temperate climates. Illustrative Genera :—There 
are two genera, Chara, Linn.; and Nitella, Agh. ; and about 40 
species. 
Properties and Uses.—These plants during their decay give 
off a very foetid odour, which is regarded as most injurious to 
animal life. They have no known uses. 
Order 4. Ata, the Sea-weed Order.—Diagnosis.—Paren- 
chumatous plants, growing in salt or fresh water, or in moist 
situations. The thallus is foliaceous and branched (fig. 5), or 
filamentous (jigs. 861 and 862), or pulverulent. Many Algze 
are microscopic, and others are of large size. In colour they 
are usually greenish, rose-coloured, or brownish. They are 
reproduced in various ways. (See pages 392-399.) 
Division of the Order and Illustrative Genera.—The order is 
commonly divided into three sub-orders, which are frequently 
regarded as distinct natural orders ; these are known under the 
names of the Melanosporex, Melanospermex, or Fucoidex ; Rhodo- 
sporexe, Rhodospermex, or Floridee ; and Chlorosporex, Chloro- 
spermex, or Confervoidex. To these sub-orders or orders may be 
added two others, called respectively the Diatomacex and 
Volvocineex. Numerous other arrangements of the Algz have 
been proposed of late years, but as these must be regarded as 
transitional, we have retained the above-named sub-orders from 
their being more generally used in this country in works treating 
practically of the Algze ; and must refer those desiring detailed 
information in reference to other arrangements to such works 
as Sachs’ ‘Text Book of Botany,’ &c, and to special treatises on 
this group of plants. Reference should also be made to pages 
392-399 of this Manual for a general notice of their Reproductive 
Organs. Their distinctive characters may be briefly described 
as follows :— 
Sub-order 1. Melanosporex, Melanospermex, Fucoidex, or 
Brown-colouwred Alge.—Multicellular Algze, growing in salt 
water, forming a foliaceous or filamentous thallus, and of an 
olive-green or olive-brown colour. Illustrative Genera :— 
Sargassum, Rumph.; Fucus, Linn. 
Sub-order 2. Rhodosporee, Rhodospermex, Floridex, or Rose- 
coloured Alge.—Marine multicellular Algze, with a foliaceous 
or branched filamentous thallus, and of a reddish-purple, 
rose-coloured, or reddish-brown colour. Illustrative Genera: 
—Corallina, Towrn.; Chondrus, Grev.; Porphyra, Agh. 
