HORDEUM 145 



overlapping laterals also forming two rows. Furthermore, 

 in four-rowed barley, the rachis internodes are longer (2.8 

 to 3.5 millimeters) than those in six-rowed barley, and this 

 results in a more loosely arranged spike. 



A form of four-rowed barley, Hordeum vulgare pallidum, 

 is the common barley in northern Europe, Asia, and America. 

 There are both winter and summer forms. Hordeum vulgare 

 trifurcatum is the four-rowed Nepal barley. In this, the 

 lemmas each have three pronged awns which bend back in 

 the form of small horns or hoods (Fig. 49). It is also often 

 called "hooded barley." There are both naked and hulled 

 hooded barleys. Hordeum vulgare coerulescens is blue barley, 

 H. vulgare nigrum, black barley, and H. vulgare coeleste, the 

 hull-less Jerusalem barley. 



Hordeum vulgare intermedium (medium or hybrid barley). — 

 Under this name are included those barleys that are transition 

 forms between the two- and many-rowed types (Fig. 52). In 

 these intermediate forms, only the two middle rows are nor- 

 mally formed, the four lateral ones being beardless and smaller. 

 It is quite probable that the intermedium forms are segregates 

 of the hybrids of certain two-rowed and many-rowed forms. 



Hordeum distichon (two-rowed barley). — In this, the 

 spikes bear two longitudinal rows of grains. As in six-rowed 

 barley, the spikelets occur in groups of three on opposite 

 sides of the rachis, but in the case of two-rowed barley, the 

 lateral spikelets of each triplet do not mature, only the middle 

 one of each maturing its grain (Figs. 49 and 52). However, 

 the glumes of the lateral spikelets develop normally. The 

 anthers of side spikelets may be either dwarfed or well 

 developed. The kernels of two-rowed barleys are symmet- 

 rical and broadest in the middle. The hull is thin. There is 

 a low percentage of. protein and a mealy endosperm. 



There are four rather common types of two-rowed barleys : 



