358 THE WHEAT PLANT 



its sheath and reduced blade sometimes appearing like a spathe of the 

 inflorescence. 



This deformity is met with in all races of wheat and is caused by a 

 parasitic fungus. 



iii. VARIEGATED LEAVES. Plants with white longitudinal stripes along 

 the leaves are occasionally found in T. dicoccoides and T. vulgare. In the 

 examples I have seen, the abnormality is hereditary and chiefly confined 

 to the young leaves, those of the culm being uniformly green. The 

 edges of the variegated leaves are usually pink. 



iv. BRANCHED EARS. Many forms of T. turgidum have branched ears, 

 abnormal secondary axes of variable length arising from notches of the 

 rachis in the place of ordinary spikelets. The character is also seen in 

 T. dicoccum, from which I consider that T. turgidum has arisen. It not 

 infrequently appears among hybrids of T. dicoccum, and is seen occasion- 

 ally in T. polonicum, but is uncommon in other races. The development 

 of secondary ears is hereditary in certain forms, but the degree of branch- 

 ing is very largely dependent upon climatic and soil conditions. The 

 morphology of these ears is discussed in the description of Miracle or 

 Mummy wheat (p. 256). 



v. TWIN EARS. Two ears are occasionally found at the apex of a single 

 straw. Shirreff records such a variation, both the twin ears being perfect 

 in form, one containing forty-five grains, the other thirty-six. In all the 

 cases I have seen, it is the rachis which bifurcates, as in Fig. 216, and not 

 the culm. An example with the rachis divided near the base is figured in 

 the Gardeners' Chronicle and Agricultural Gazette for 1849 (p. 363). 



The production of twin ears I have only seen in T. vulgare. It is not 

 hereditary and is much less common, and quite a different phenomenon 

 from the branching of the ears so frequently seen in forms of T. turgidum. 



vi. SHORT EARS. Short stumpy ears consisting of three to seven 

 spikelets are found occasionally in T. vulgare and T. turgidum. 



The spikelets are of normal size and form and develop well-filled 

 grain. The terminal spikelet, unlike the arrangement in normal ears, is 

 parallel to the rest. Possibly the true apex of the rachis is destroyed in 

 its early development by a parasite, although there is no evidence of such 

 damage in the mature ears. 



The variation is not hereditary. 



vii. SMALL MALFORMED EARS, generally on short sinuous culms, appear 

 not infrequently among the progeny of hybrids between distinct races of 

 wheat, more especially when T. dicoccoides or T. dicoccum is one of the 

 parents (see Fig. 220). A number figured by Buffum were obtained 

 among the F x of a cross between a " mutating " T. dicoccum and a " sport " 

 of Turkey Red wheat (T. vulgare). 



