16 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
GENERA HERE EXCLUDED. 
The genus Panicum as accepted by Dalla Torre and Harms? includes 
a number of groups which in our treatment have been excluded. Of 
the twelve sections into which Panicum is there divided, the first 
eleven belong to allied genera, as do Streptostachys and Otachyrium 
of the twelfth section. Coleataenia Griseb. from South America, — 
included in the twelfth section, is a true Panicum. 
Jn addition to the groups mentioned above, several species referred 
by many authors to Eupanicum have been excluded. 
Sacciolepis Nash? has been discussed by Chase.° This genus has 
been confused with Hymenachne Beauv. on account of the similarity 
in the form of the inflorescence, which is usually a spike-like panicle. 
The genus is chiefly distinguished by the saccate second glume and 
stipitate fruit. 
Lasiacis (Griseb.) Hitche. (Panicum, section Lasiacis Griseb.),@ 
includes the woody, bamboo-like species with globose spikelets hay- 
ing a bony-indurated fruit, with a downy tuft at the apex, the palea 
gibbous above and concave toward the base. The type of this genus 
is Lasiacis divaricata (L.) Hitche., based on Panicum divaricatum 
L., the type of Grisebach’s section. 
Panicum uncinatum Raddié is here excluded from Panicum 
because of the distinctly different spikelets placed with the back of 
the fruit turned from the rachis, the narrow, aristate first glume as 
long as the spikelet, the large boat-shaped second glume beset with 
divergent, uncinate spines, the sterile floret large and having a 
subindurated lemma and palea, the fertile floret about two-thirds as 
large as the sterile one, the margin of the lemma not inrolled—a com- 
bination of characters showing a closer approach to Echinolaena than 
to Panicum. 
Panicum aturense H. B. K./ is also here excluded, differmg from 
Panicum as here limited in having equal glumes exceeding the sub- 
hyaline sterile lemma and a scarcely indurated fruit, the margins of 
the lemma thin and flat. 
Panicum tuerckheimii Hack.,9 of which we have seen but a single 
specimen (Tuerckheim’s no. 8618, a duplicate type), is an anomalous 
species with spikelets in which the first glume is wholly wanting, and 
in which no rudiment of a palea is found in the sterile lemma. 
The genus Lasiacis and the other species here excluded from 
Panicum will be separately considered in a subsequent paper. 
a Gen. Siphonog. 13. 1900. é Acrost. Bras. 41. 1828. G 
6 Britton, Man. 89. 1901. f Nov. Gen. & Sp. 1:108. pl. 88. 181p. 
¢ Proc. Biol. Soc. Washington 21: 6.1908. g Allg. Bot. Zeitschr. 12: 60. 1906. 
d¥l. Brit. W. Ind. 551. 1864. 
