ROLL CALL 



m 



mesoderm) ; (3) the nature of the body — usually divisible into tubes 

 within tubes or sacs ; (4) the symmetry — radial or bilateral ; (5) the 

 nature of the appendages — if present, whether jointed or non-jointed, 

 paired or unpaired ; (6) whether the organism is segmented or non- 

 segmented ; (7) which organ systems or organs are present, in what 

 form they occur and how they function ; (8) type of skeleton, ab- 

 sent, exo- or endoskeleton ; (9) the presence or absence of a noto- 

 chord ; (10) the presence or absence of special organs ; (11) the type 

 of tissues present, as bark, phloem, muscular, or circulatory. 



Inasmuch as some of these and other terms appearing in the scheme 

 of classification are new, a short glossary is included. This is designed 

 to elucidate terms used in the appended classification. Other words 

 are defined as they are first used in the text and may be found by 

 reference to the index. 



CLASSIFICATION OF THE PLANT KINGDOM 



(mainly after Sinnott) 



All members of the plant kingdom are characteristically ses.sile ; typically 

 possess chlorophyll; usually take food in inorganic form; cell walls of cellulose 

 or hydrocarbon. 



DIVISION I — THALLOPHYTA — Thallus Plants (algae,' fungi, bacteria). 

 Chabacteristics : Small, often minute, little differentiated plants some- 

 times possessing chlorophyll; se.x organs, when present, typically one 

 celled ; spore-bearing organs are single celled ; 80,000 species. 



Subdivision A — Algae — Composed mostly of blue-green, green, brown, or red 



algae. 

 Characteristics : Chlorophyll frequently associated with other pigments ; 

 manufactures own food. 



Class I — Cyanophyceae — Blue-green algae {Gloeocapsa, Nostoc, Oscilla- 

 tor ia). 

 Characteristics : Simplest and lowliest of green plants ; body consists of a 

 single cell with nucleus ; sap cavity and chloroplasts absent ; often tend- 

 ing to adhere in colonies; usually in threadlike rows ( filaments); cyto- 

 plasm homogeneous, pigment evenly dispersed, or a colored outer and a 

 colorless inner zone may be distinguishable ; blue-green color probably due 

 to chlorophyll mixed with blue pigment (phycocyanin) . 



Class II - Chlorophyceae - Green algae (Cartena, Ulva, Ulothrix, Oedogo- 

 nium, Vaucheria, Spirogyra). 



1 Genera in boldface type indicates that the form is illustrated in this unit. 



