ch. vn] Botanical Description of Species 



109 



H. lanatus by (1) both its empty glumes being acute at the top, 

 and rather larger, (2) the lateral nerves of the upper glume being 

 closer to the keel than to the margin, and (3) the awn of the 

 upper flower being more dorsally situated and rough (a microscopic 

 character) throughout its entire length, and bent— but not curved 

 back — when mature. These differences will of course serve to 

 distinguish the "seeds." (Fig. 116.) 



Hordeum. In this genus the inflorescence is Sfihale. The 

 spikelets are one-flowered, and are arranged in alternating groups 

 of threes on opposite sides of the rachis. 



A B 



Fig. 114. A. " Seed " of Holcus lanatus consisting of the entire spikelet. B. Con- 

 tents of the spikelet A. The imperfectly developed upper flower readily 

 separates (as shown) from the rachilla of the lower pair of palese. The grain is 

 enclosed by the latter and is a very common impurity in many kinds of 

 commercial seeds. It may either remain attached within the glumes or 

 become free from them, x 10. 



Hordeum murinum, L. (Wall Barley.) (Fig. 117.) 



A closely tufted annual with abundant light-green foliage. 

 Sheaths split, slightly keeled, hairy (at least the lower ones). Blade 

 rolled in the shoot, broadest about its middle, acuminate, rather 

 thin ; both surfaces dull and hairy, ribless above, slightly keeled 

 below. Ligule short and blunt. Auricles large, white, pointed 

 and overlapping. Common in Britain as a weed in waste places. 



Inflorescence and "Seeds." 



Flowers in June; culms 1 to 2 feet high. Inflorescence a 

 spike of spikelets. Spikelets one-flowered, arranged in alternating 

 triplets on the flattened sides of the notched rachis. The three 



