SORGHUM 



SORGHUM 



575 



spike-like panicle in Orange and Sumac sorghums, 

 kafirs, and others ; and a dense, ovate or globose, 

 head-like panicle in many durras; the rachis or 

 central axis of the panicle 

 greatly shortened in the corym- 

 bose forms, as broom-corns, 

 from one-half as long as to 

 equaling the panicle in sweet 

 sorghums, and nearly equaling 

 it in kafir and durra varieties; 

 spikelets in pairs, one sessile, 

 fertile, prominent, the other 

 stalked, sterile, slender, less 

 conspicuous, and falling off 

 readily at maturity; seeds oval, 

 obovate, subglobose or lenticu- 

 lar in shape; white, pearly, yel- 

 lowish, reddish yellow, red or 

 reddish brown in color ; shorter 

 than the empty glumes (in- 

 cluded) or longer (exserted); 

 empty glumes (hulls or outer 

 chaff) usually thick, leathery, 

 much shorter than to longer 

 than the seed, rounded or acute 

 at the apex; normally greenish 

 white while" immature, some- 

 times remaining so in maturity, 

 in other varieties becoming dif- 

 ferent shades of red, brown and 

 black, more or less silky-hairy, 

 at least while young, some 

 forms almost glabrous at ma- 

 turity ; flowering glume thin, 

 transparent, awned or awnless. 



Groups. 



The cultivated sorghums of 

 this country may properly be 

 divided into five groups, as 

 follows : broom-corns, shallu, 

 sweet or saccharine sorghums, 

 kafirs, and durras. Popularly 



' 



some of the kafirs have a fairly sweet juice and 

 could doubtless be developed into saccharine 

 varieties. The term kaoliang, mentioned on page 

 572, designates Chinese varieties in general, it 

 being the Chinese name for sorghums. 



KEY TO GROUPS 

 A. Pith dry : 



Head loose, 10-28 inches long ; 

 spikelets oval or obovate, 

 small : 

 Rachis very short ; seeds 



reddish 



Eaohis as long as head ; seeds 

 white or pearly . . 

 Head compact, 4-9 inches long ; 

 spikelets broadly obovate, 



large V. Durra 



Pith juicy : 

 Juice abundant and very sweet. IH. Sorghum 

 Juice scanty, subacid or some- 

 what sweet : 

 Heads erect, cylindrical ; 



spikelets oval, small . . IV. Kafir 

 Heads pendent, ovate ; spike- 

 1 e t s broadly obovate, 



V. Durra 



I. Broom-corn 

 11. Shallu 



AA. 



I. Broom-corn. (Pig. 809 ; also Fig. 309.) 



Description. — Pith dry ; internodes usually longer 

 than the sheaths ; peduncles erect ; panicles corym- 

 bose or umbellif orm, 10-28 inches ; rachis one to 

 two inches long; spikelets obovate, mostly awned ; 

 glumes acute or obtuse, equaling the seeds. 



History. — The origin of broom-corn is not known. 

 It was probably derived by selection from a sweet 

 sorghum having elongated branches and a shortened 

 rachis. This selection was very probably made in 

 Italy several centuries ago. The first mention of 

 the use of this plant in broom-making is from an 

 Italian source, and sorghums have been cultivated 

 in Italy for eighteen centuries or more. 



Varieties. — There are only two recognized agri- 

 cultural varieties of broom-corn, the standard and 

 the dwarf. The standard is characterized by stalks 

 10-15 feet high and a panicle or brush 15-28 inches 

 long, usually fully exserted from the upper sheath 

 or "boot." Its seed is sold under several names, but 

 these do not represent forms with recognizable dif- 

 ferences. The dwarf form grows only 3-6 feet 

 high, with a panicle 10-18 inches in length, 

 usually partly enclosed by the upper sheath. 

 [See Broom-corn, page 216.] 



they are classed as broom-corns, saccharine sor- 

 ghums and non-saccharine sorghums, the last class 

 including both kafirs and durras. The term non- 

 saccharine is cumbersome and not distinctive, as 



II. ShaUu. 

 Description. — Pith dry ; internodes 

 about equaling the sheaths ; pe- 

 duncles erect ; panicle large, 

 10-15 inches long, ovate- 

 pyramidal, loose and open, 

 pale yellow, 

 branches com- 

 monly droop- 

 ing ; rachis as 

 long as the panicle ; spikelets elliptical-lanceolate, . 

 awned ; empty glumes straw-colored, hairy, becom- 

 ing gaping and inrolled at maturity ; seeds oval, 

 flattened, white or pearly, hard, fully exposed at 



