.SKOT. 1 



CRYPTOGAMS 



359 



from asexual swarm -spores (.VNDUosj'oiiE.s) which, after swarming, attach them- 

 selves to the female lilaments, or even to the oogonia. In the upper cells of the 

 dwarf male filaments thus derived from the androspores, spermato/oids are pro- 

 duced which are set free by the opening of a cap-like lid (Fig. 291 l>, a). 



The genus Coleochacle (*) is also oogamous. The long colourless neck of the 

 Mask-shaped oogonium opens at the tip to allow of the entrance of the spermatozoid. 

 The spherical oospore increases in size and becomes surrounded by a single layer 

 <>f pseudo-parenchymatotis tissue derived from filaments that spring from the 

 stalk cell of the oogonium and neighbouring cells. In this way a fruit-like body 

 is formed. On germination the oospore first divides into 16-32 wedge-shaped 

 cells, then breaks up and liberates a swarm-spore from each cell. While in regard 



BH 



1 



I'H.. $01. A, I!, ii' iliHioiiiinu : A, escaping swiinn - spores : /;. 

 tree suMi-iii-spore. <', 1), Onlixjniinnn i-ilintinn : ' ', Ix-fore fer- 

 tilisation ; 7), in process nl' fertilisation : . ooj;onia : n, <!>.v;irf 

 males : N. s]iiT!M;itn/oiil. (After I'm xcsHKlM, X 350.) 



/;, 



formation of tour swarni- 

 s]H>res in tin- x'Tiiiiniitinx 

 oospore. (After I'KIM;-.- 

 II KIM, X '-'"lO.) 



to these processes (Jvlcochaete exhibits the highest grade attained by the Green 

 Algae, it cannot be regarded as the point of origin of the Bryophyta. 



Order 4. Siphonocladiales. The Algae of this order are filamentous and 

 usually branched ; they are distinguished from the Ulotriehales by their large 

 multinucleate cells, the chloroplasts of which are either solitary, large and reticn- 

 lately formed, or appear as numerous small discs.- 



The genus I'liiiLn/ilnn-n. numerous species of which occur in the sea and in fresh 

 water, is one of the most important representatives of the order. Cl. glomerate 

 (Fig. 29-'5) is one of the commonest Algae in streams, often attaining the length of 

 a foot. It is attached by rhizoid-like cells, and consists of branched filaments with 

 typical apical growth which some other representatives of the order do not show. 

 The structure of the cells is represented in Fig. 61. Branching takes place from 

 the upper ends of the cells by the formation of a protrusion which is cut off as the 

 first cell of the branch. Asexual reproduction is by means of biciliate zoospores 

 (Fig. 293), which arise in numbers from the upper cells of the filaments, and cse.-ipe 

 from these sporangia by a lateral opening in the wall. The sexual reproduction is 

 isogamous as in ( 'fothrix. 



Only in the genus Sphneroplca has the sexual reproduction become oogamous. 

 S. annulinu consists of simple filaments and occurs in fresh water. 



Many Conns occur in the sea (e.<j. Sipkonockuhu), and some have a highly com- 

 plicated thallus. which is always, however, formed of branched filaments ; by 



2 A 3 



