TYPES OF AMERICAN GRASSES: A STUDY OF THE AMER- 
ICAN SPECIES OF GRASSES DESCRIBED BY LINNZEUS, 
tRONOVIUS, SLOANE, SWARTZ, AND MICHAUX, 
By A. 8. Hrrencock. 
INTRODUCTION. 
During the spring of 1907 I had the opportunity of examining 
many types of American species of grasses deposited in European 
herbaria. In the present paper I have considered the species of 
grasses described by Linneus, Gronovius, Sloane, Swartz, and 
Michaux, the first only so far as they are based upon American ma- 
terial. No attempt is made to determine the types of Old World 
species. 
Since the older authors did not indicate their types, these must be 
determined from the records which have been preserved. The type 
specimen is the specimen or one of the specimens from which the 
author drew up the description. The specimen often supplements 
or interprets the description. If the author mentions in his original 
description a definite specimen, if this specimen has been preserved 
and its identity certified by the data upon the label and by the name 
of the species added by the author, it is clear that this specimen is 
the type. However, it often happens that the evidence is less com- 
plete. An author may have based his description upon more than 
one plant (Panicum pubescens Lam., see page 147); the supposed type 
may not agree perfectly with the description (Andropogon ischaemum 
L., page 126); the author may have written the name upon more than 
one sheet or upon a sheet which is not mentioned in the description 
(Panicum latifolium 1.., page 118); the locality or other data on the 
label of the type specimen may not agree with that published 
(Zizania fluitans Michx., page 156); the type specimen may have been 
sent to another herbarium (Panicum dichotomiflorum Michx., page 
147); the type specimen may be accompanied by a specimen of a dif- 
ferent species upon the same sheet (Panicum dichotomum L., page 117) ; 
or the type specimen may bear a name on the label which is different 
from the one published (Chloris monostachya Michx., page 152); or 
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