CLASSIFICATION OF AMERICAN WHEAT VARIETIES. 185 
la. Spike Awned— Continued. 
2b. Glumes Pubescent. 
3a. Glumes White. 
4a. Awns Black. 
5a. Kernels White ( T. d. melanopus Al.). 
Kernels Long, Hard. Page. 
Beaks 1-2 mm. long Velvet Don 191 
Beaks 1-5 mm. long Golden Ball 191 
3b. Glumes Black. 
4a. Awns Black. 
5a. Kernels White ( T. d. taganrogeme Desv.), 
Kernels Long, Hard. 
Beaks 1-2 mm. long Kahl a 192 
DESCRIPTIONS, HISTORY, DISTRIBUTION, AND SYNONYMY OF DURUM WHEAT 
VARIETIES. 
PENTAD (D-5). 
Description. — Plant spring habit, midseason, midtall ; stem white, midstrong ; 
spike awned, fusiform, middense, inclined ; glumes glabrous, white, midlong, 
midwide ; shoulders midwide, oblique to elevated ; beaks 1 to 2 mm. long ; 
awns white, 5 to 15 cm. long; kernels red, midlong, hard, ovate, truncate tip, 
humped ; germ midsized ; crease midwide, shallow ; cheeks angular ; brush 
midsized, short. 
The Pentad or D-5 (Durum No. 5) variety is distinct from all other com- 
mercial varieties of durum wheat grown in the United States because of its 
red kernels. They are smaller, squarer at the brush end, and more pointed at 
the germ end than kernels of the other durum varieties. Experiments have 
shown it to be the most rust-resistant variety of wheat grown in the United 
States, and therefore it yields well under conditions favoring rust. Its milling 
and baking value, however, has been found to be inferior to other durum varie- 
ties. A spike, glumes, and kernels of Pentad wheat are shown in Plate LfV, A. 
History. — The Pentad variety was introduced from Russia in 1903 by Prof. H. 
L. Bolley, of the North Dakota Agricultural Experiment Station. The wheat was 
distributed in several sections of North Dakota by Professor Bolley in the 
spring of 1911. Because of its rust resistance it gained popularity and has 
recently become widely distributed in the durum-wheat section, but its poor 
milling quality has caused its distribution to be opposed by many agencies. 
The name Pentad is derived from penta, meaning five in Greek, plus d, which 
stands for durum. The name was suggested to the North Dakota station by 
the senior writer in 1917. It has recently been used by Professor Bolley as a 
name for D-5, and was first recorded by Trowbridge {196, p. 17) in 1920. 
Distribution. — Pentad was reported in 1919 from Minnesota, Montana, Ne- 
braska, North Dakota, South Dakota, and Wyoming. It is grown principally in 
North Dakota. 
Synonyms. — " D-fife," Ladd Durum, Red Durum, Resistant Fife, and Rust 
Proof. 
The name " D-fife " is often but wrongly used by many farmers in North 
Dakota. The practice is easily accounted for, as the numeral 5 has been mis- 
pronounced as fife. Ladd Durum is a name used in the grain trade for Pentad 
wheat under the supposition that Dr. E. F. Ladd, formerly of the North Dakota 
Agricultural College, was the originator. Red Durum is a name commonly 
used for Pentad wheat, as it is the name of the subclass under which the grain 
of this wheat is graded under the Official Grain Standards. Resistant Fife 
and Rust Proof are names used for Pentad wheat on the farms, because the 
variety has proved to be resistant to stem rust. 
