132 ALGAE IN PHYTOPLANKTON OF THE UNITED STATES 



Ovate, ovoid (adj). Oval; egg shaped. 



Palmella (n), palmelloid (adj). A genus of green algae, whose spherical cells are united 



by their mucilage coats into indefinite mucilaginous masses. 

 Parietal (adj). Pertaining to or near the wall. 

 Periphery (n). The outer boundary or edge. 

 Periphyton (n), periphytic (adj). The community of micro-organisms that are attached 



to or live upon submerged surfaces. 

 Phytoplankton (n), phytoplanktonic (adj). The plant part of the plankton. 

 Plankton (n), planktonic (adj). The community of suspended or floating organisms that 



drift passively with water currents. 

 Polar (adj). Pertaining to the pole or end. 

 Polyhedral (adj). Having numerous faces or planes. 

 Postcingular (adj). Referring to position of plates adjacent to the girdle of the 



hypotheca of certain dinoflagellates. 

 Precingular (adj). Referring to position of plates adjacent to the girdle in the epitheca of 



certain dinoflagellates. 

 Protoplast (n). The living contents of a cell; the nucleus, cytoplasm, and plasma mem- 

 brane that constitute a living unit. 

 Pseudoraphe (n). The axial field of the valves of pennate diatoms lacking a longitudinal 



cleft or raphe. 

 Pseudovacuole (n). A false vacuole; a pocket of gas or fluid within the protoplast. 

 Puncta, punctae (n), punctate (adj). A tiny spot, dot, point, or depression. 

 Pyramidal (adj). Pyramid shaped. 

 Pyriform (adj). Pear shaped. 

 Quadrate (adj). Square; arranged in fours. 

 Quadriflagellate (adj). Having four flagella. 



Radial (adj). Radiating from a common center or point; pertaining to the radius. 

 Raphe (n), rapheal (adj). A longitudinal cleft in the axial field of certain pennate 



diatoms. 

 Recurved (adj). Curved; bent down. 

 Reniform (adj). Kidney shaped. 

 Reticulate (adj). Like a network. 

 Rhombic (adj). Resembling a rhomboid. 

 Rostrate (adj). Having a beak. 



Semicell (n). One-half of a vegetative cell of a desmid. 

 Sessile (adj). Pertaining to an organism that is attached to an object. 

 Seta, setae (n). A slender, more or less rigid bristle, a short hair. 

 Sheath (n). A covering, envelope, or tube that is composed of mucilage. 

 Sigmoid (adj). S-shaped. 

 Solitary (adj). Single; alone. 

 Spherical (adj). Sphere shaped; globular. 

 Spicate (adj). Having spikes or spines. 

 Spine (n). A stiff, pointed process. 



Stalk (n). A supporting structure, generally mucilage, affixed to a substrate. 

 Statospore (n). An asexually formed spore having thick silicified walls composed of two 



overlapping halves. 

 Stauros (n). A thickness and transversely expanded central nodule interrupting the 



raphe of certain diatoms. 

 Stellate (adj). Star shaped. 



Stria, striae (n), striate (adj). Long delicate markings on the frustules of diatoms. 

 Subacute (adj). Almost pointed. 

 Subcylindrical (adj). Almost cylindrical in shape. 



