4 BULLETIN 1386, U. S. DEPARTMENT OF AGRICULTURE 
scribed by early European and American botanical writers as 
well as by contemporaneous writers. A bibliography of sorghum, 
including works on classification, is given by Ball (2). Linne (10, 
p. 1047) listed three types as species in his "Species Plantarum," 
differentiating them as follows: (1) "Glumis villosis, feminibus 
aristatis, Holcus sorghum''''; (2) "Glumis glabris, feminibus muti- 
cis, Holcus saccharatus" ; and (3) "Glumis glabris, floribus her- 
maphroditis muticis, femineo aristato, Holcus halepensis." The 
third type is the spontaneous species commonly known in the United 
States as Johnson grass. In his Mantissa Plantarum (11, p. 301) 
Linne published as a species a fourth type, as follows: "Glumis 
glabris nigris, feminibus globosis albis aristatis, Holcus bicolor" 
Forskal (7, pp. 174—175) described as species four types, with a 
varying degree of completeness. One especially, Dochna, he de- 
scribed at some length, including characters of the culm, leaves, 
and panicle and noting the arrangement of the branches of the 
latter, as well as the form and color of the sessile and pedicellate 
spikelets. He also described the caryopsis of this variety as being 
"the size of rice, oval, compressed, ferruginous, tightly held by the 
glumes, which have gaping apices." 
Arduino (1) described six types, called by him species of Holcus. 
and presented excellent illustrations of the panicles, the fertile and 
sterile spikelets in one or more stages of development, and in some 
varieties the caryopsis. He designated certain types as varieties 
of the so-called species. These differed mainly as to color and form 
of the seeds or in other minor particulars. His main types, or 
species, were as follows: (1) Holcus cafer, having an abbreviated 
central axis and which he also states had rounded seeds and small, 
hairy, easily separated glumes; (2) Holcus cernuus, having a re- 
curved panicle with spikelets awned and hairy, glumes ash colored, 
and seed flattened; (3) Holcus sorghum, having an open, spreading 
panicle, reddish or yellowish seeds which were awned, and indurated 
glumes not easily separated from the grain; and (4) Holcus bicolor, 
with somewhat verticillate panicles and acute seed grains which 
exceeded the black and white glumes. Referring to minor types, 
he states that there were, for example, varieties of Holcus sorghum 
which had seeds shining and red, shining and ferruginous, yellow 
and glabrous, yellow and hairy, and others reddish; that the seeds 
varied much in form, being described as rounded and covered, 
rounded and half bare, and angular; that there were both awned 
and muticate types; and that there were also varieties which were 
distinguishable by the height of the stalk, these varying from 3 to 
about 10 feet. 
Kornicke (9, pp. 299-315) described 12 types as varieties of An- 
dropogon sorghum, grouping them first, according to the forms of the 
panicle, in two classes, Effusus and Contractus. These two main 
groups were subdivided, the first according to the length of the rachis 
and the second as to whether the panicle was erect or recurved. The 
varieties within these subgroups were separated according to the 
color of the glumes and the caryopsis and by the form of the panicle. 
Hackel (8, pp. 499-520) presented descriptions of 36 cultivated 
types, both sweet and nonsaccharine, as varieties of Andropogon 
sorghum, subspecies sativus. He divided the varieties represented in 
