ALG& CONTINUED: CLASSIFICATION. 



171 



Classification. Kjellman divides the Phaeophyceae into two orders. 



369. Order Phaeosporales (Phaeosporeae) including 18 families. One of 

 the most conspicuous families is the Laminariaceae, including among others 

 the Giant Kelps mentioned above (Laminaria, Postelsia, Macrocystis, etc.). 



370. Order Cyclosporales (Cyclosporeae). This includes one family, the 

 Fucacece with Ectocarpus, Sphacelaria, Laeathesia, Fucus, Sargassum, etc. 



Class Rhodophyceee. 



371. The red algae (Bhodophyceae). The larger number of the so-called 

 red algae occur in salt water, though a few genera occur in fresh water. 

 The plants possess chlorophyll, but it is usually obscured by a reddish or 

 purple pigment. 



372. Nemalion. This is one of the lower marine forms, though its thal- 

 lus is not one of the simplest in struc- 

 ture. The plant body consists of a 



slender cylindrical branched shoot, some- 

 times very profusely branched. The 

 central strand is rather firm, while the 

 cortex is composed of rather loose fila- 

 ments. 



373. Batrachospermum. This genus 

 occurs in fresh water, and the species 

 are found in slow-running water of 

 shallow streams or ditches. There is a 

 central slender strand which is more or 

 less branched, and on these branches 

 are whorls of densely crowded slender 

 branches occurring at regular intervals. 

 The plants are usually very slippery. 

 Gonidia are formed on the ends of some 

 of these branches in globose, sporangia, 

 called monosporangia, since but a single 



Fig. 182. 



.,. , . . . A red alga (Nemalion). A, sexual 



spore or gonidium is developed in each, branches, showing antheridia (a); 



Other branches often terminate in long 



slender hyaline setae. two spermatia (s); B, beginning of 



Qiryi T rr^i a cystocarp (o), the trichogyne (/) 



374. Lemanea. This genus also occurs still showing; C, an almost mature 



in fresh water. The species develop g 



only during the cold winter months in 

 rapids of streams or where the water from falls strikes the rocks and is 

 thoroughly aerated. They form tufts of greenish threads, cylindrical or 

 whiplike, which in the summer are usually much broken down. The 

 threads are hollow and have a firm cortex. These are the sexual shoots, 



