FAMILY TETRASPORACEAE 



In this family colonies of spherical cells bearing long, fine hair-like 

 pseudocilia are embedded in copious mucilage. The pseudocilia are 

 extensions from the protoplast; because they are extremely fine, fav- 

 orable optical conditions or special staining may be required in order 

 to distinguish them. The cell contents are as described for the order, 

 the chloroplast being a parietal cup or plate covering most of the 

 cell wall. 



The cells usually remain in groups of 4 after division of the parent 

 cell and in most forms are disposed at the periphery of the colonial 

 mucilage. The colony may be amorphous or somewhat definite in 

 shape. 



Key to the Genera 



1. Plant mass mucilaginous, amorphous or intestiniform, macroscopic.- ._ 2 



1. Plant mass of definite shape, microscopic 3 



2. Plant an amorphous, usually floating, mass of mucilage in which 

 fragments of old cell walls remain Schizochlamys 



2. Plant an elongate, tubular, or intestiniform, gelatinous thallus, 

 with cells arranged at the periphery of the mucilage; 



fragments of old cell walls lacking Tetraspora (in part) 



3. An attached pyriform gelatinous thallus. _____ _ ...Apiocystis 



3. A free-floating, globular thallus of few cells, 



embedded in homogeneous gelatin .-.Tetraspora (in part) 



TETRASPORA Link 1809, p. 9 



Thallus a gelatinous sac, or a tubular or membranous mass, con- 

 taining spherical cells arranged in 2's and 4's. Chloroplast parietal, 

 bell-shaped, covering almost the entire wall, with 1 pyrenoid. Cells 

 often showing long, extremely fine pseudocilia which extend far 

 beyond the limits of the colonial mucilage; thallus attached, at least 

 when young, forming bulbous or vermiform masses, later becoming 

 free-floating green skeins or sheets; rarely globular and euplanktonic. 



Some species of Tetraspora occur in early spring and are among 

 the first plants to develop in ditches and streams of cold water after 

 the melting of ice. They may continue on in favorable habitats 

 throughout early summer. Draparnaldia spp. are commonly found 

 associated with Tetraspora. 



Key to the Species 



1. Thallus cylindrical at all ages, attached; narrowed and 



constricted below to form a short stipe T. cylindrica 



1. Thallus not cylindrical at all ages, becoming bullate or expanded 2 



2. Cells with individual, thick gelatinous sheatlis T. lamellosa 



2. Cells without individual sheaths, or with sheaths thin and diffluent 3 



3. Thallus an attached gelatinous sac, becoming bullate and lobed .. T. gehtinosa 

 3. Thallus not an attached, bullate, or lobed sac 4 



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