7. Rhizomes and Stolons 



Grasses have fine fibrous root systems. Many grasses have a thickened, generally whitish, creep- 

 ing underground stem or rhizome. These rhizomes send up new shoots from the nodes and enable the 

 plant to spread vegetatively. Other grasses have prostrate, above-ground, creeping stems or stolons 

 which also root at the nodes or tips. The presence or absence of rhizomes or stolons frequently is a 

 great help in distinguishing one species from another. 



8. Inflorescence 



The common forms of grass inflorescence (flowering parts) are the spike (quackgrass), raceme 

 (crabgrass) and panicle (redtop). The character of the inflorescence is not used as a basis of sepa- 

 ration in this vegetative key. A simplified description of the inflorescence of each species is given, 

 however, as an aid in establishing positive identification whenever inflorescence is present. 



9. Geographical Range 



The geographical range of the various grasses in the states of the Northeast is that given by 

 Hitchcock (6) with such modifications as were indicated by the author's collections. The range 

 given is meant to be only that of general occurrence and for most grasses would also include the 

 area of the Northeast west of the state named. Some species may be occasionally found considerably 

 north of their general range. Geographical range is not used as a point of separation of species in the 

 key but in some cases may be valuable information to help in positive identification. 



10. Where Found 



Most grasses are found over a wide range of situations such as cultivated fields, meadows, open 

 ground and waste places. Others, however, are found only in rather specific locations such as bogs, 

 salt marshes and on dune sand. Where the conditions of growth are quite specific, it is a valuable 

 characteristic that can be used in separating species. 



USING THE KEY 



Many grasses are highly variable in their vegetative characters. There may be great differences 

 in the vegetative descriptions of the same species grown under different climatic conditions. Fre- 

 quently there is considerable variation among plants growing close together. For this reason, when 

 collecting a specimen for identification, it is well to gather plants from several different spots. 



In using the key, a 10X magnifier is essential. A Pocket Comparator or other device for making 

 fine measurements will also be very helpful. 



Where separations arc based on width of blade or length of ligule, reference is to the widest 

 blades or the longest ligules (unless otherwise specified) present on the specimens. 



The characters given in the key arc arranged in pairs bearing the same number but different 

 letters as la, lb; or 12a, 12b. The two parts of any pair are opposing or partly opposing characters. 

 No grass plant can fit both ; every plant should fit one or the other. 



With a given grass in hand read both parts of the first pair, "la. Blade more than 3 mm. wide 

 — lb. Blade less than 3 mm. wide." If this particular specimen has blades more than 3 mm. wide 

 read next pair 4, as directed by the figure at the end of that line. If a ligule is present (4a) go next 



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