ZAUSCHXERIA 



3539 



with slight winter covering. In favored spots it is con- 

 sidered to be a choice plant of pendent habit for the 

 steep sides of rockeries and for naturalizing on old 

 walls. In light and dry soils it spreads underground 

 like the epilobiums. It is prop, by division, by cuttings 

 made in autumn and wintered in a coldframe, or by 

 seeds sown in early spring in mild heat. In Calif, the 

 plant is considered objectionable on account of the 

 unkempt appearance pro- 

 duced by the woolly seeds. 

 It is remarkably resistant to 

 drought. 



WILHELM MILLER. 



ZEA (an old Greek name 

 for some common cereal, 

 probably spelt). Graminex. 

 A large annual grass with 

 monoecious infl., the stami- 

 nate fls. being in the tassel at 

 the top and the pistillate fls. 

 in one or more ears in the 

 axils of the Ivs., each ear 

 inclosed in several reduced 

 Ivs. or husks, the numerous 

 styles protruding from the 

 tip as the silk. As now limited 

 the genus is founded on the 

 single polymorphous cult, 

 species, Zea Mays, maize or 

 Indian corn (Figs. 4034, 4035, 

 4036), whose origin is un- 

 known but is suspected by 

 some to be teosinte (Euch- 

 Ixna mexicana). Most of the 

 evidence points to Mex. as 

 the region in which it origin- 

 ated and from which it 

 spread. 



After a prolonged study of 

 maize, teosinte, and hybrids 

 between them, Collins ad- 

 vances the hypothesis (Journ. 

 Wash. Acad.'Sci. 2:520. 1912) 

 that maize originated as a 

 4036. Zea Mays. Flint corn, hybrid between teosinte and 

 an unknown grass belonging 



in the Andropogoneae. This grass is thought to 

 have been not unlike the earless varieties of pod or 

 husk corn (Zea Mays var. tunicata, Figs. 4037, 4038). 

 The chief distinction between pod corn and the 

 ordinary varieties of maize is that the glumes of the pis- 

 tillate spikelets are developed in pod corn and com- 

 pletel}- inclose the grain, while in ordinary maize the 

 glumes are reduced to minute scales at the base of the 

 grain. Collins has found that if plants of pod corn are 

 isolated and bred among themselves for a few genera- 

 tions, there will usually result a still greater divergence 

 from the ordinary type of maize. Plants will appear in 

 which the lateral inflorescence or ear is aborted while 

 the terminal inflorescence is greatly enlarged, containing 

 both stamens and pistils. These may be borne 

 either in separate spikelets, in separate florets of 

 the same spikelet, or in perfect florets. Plants 

 of this earless type of pod corn possess no 

 characters which would exclude them from the 

 Andropogoneae. The constant recurrence of such 

 plants among many varieties of corn Collins 

 considers to be strong indication that some 

 perfect-flowered grass has figured in the ancestry 

 of maize. Harshberger (see G.F. 9:522; Contr. 

 Bot. Lab. Univ. Perm. 2:231) after a study of 

 teosinte-maize hybrids, showed that Zea canina, 

 Wats. (Figs. 4039, 4040), originally described as 

 a wild species, is an early-generation hybrid 

 between ordinary maize and teosinte. Harsh- 



berger concludes that Indian corn is the result of a 

 cross between teosinte and a race or variety of the 

 same species produced by successive cultivation of the 

 wild plant until its characters as a variety or race have 

 become fixed. Collins 

 holds that this con- 

 clusion does not take 

 into consideration the 

 evidence afforded by the 

 podded varieties of 

 maize. To explain maize 

 as a hybrid Collins holds 

 that the second parent 

 must be assumed to be 

 some plant radically dif- 

 ferent from teosinte, for 

 only such a parent would 

 account for the appear- 

 ance of characters the 

 very opposite of those 

 which characterize Eu- 

 chbena. Under the 

 article Corn are given 

 the botanical characters 

 of the genus, a classifica- 

 tion of the subspecies, ^ Pod or husk co . 11 ._ Zea 

 as proposed by Sturte- Mays var. tunicata. Each kernel 

 vant, and a discussion of inclosed in a bosk. ( X Ji) 

 sweet corn and pop-corn. 



The following varieties of Zea Mays are grown for 

 ornament : 



Var. japonica, Koern. (Z. japdnica, Van Houtte. 

 Z. vittata, Hort.). Foliage variously striped with white: 

 plant small: ears small; kernels yellowish, flint. Said 

 to have come from Japan. F.S. 16:1673, 1674. G. 

 2:463. 



Var. gracfllima, Koern. (Z. gracittima and Z. minima, 

 Hort.). Very dwarf, slender form with green Ivs., some- 

 times cult, in Eu. A var. variegata is also mentioned. 



Var. Curagua, Alef. (Z. Curagua, Molina), is 

 described as a very robust green-lvd. form. Sturtevant 

 places it in the pop-corn tribe. Gn. 42, p. 207. 



A. S. HITCHCOCK. 



ZEBRINA (name 

 refers to the striped 

 leaves). Cammeli- 

 nacex. One of the 

 species, the wander- 

 big Jew, is a very 

 common greenhouse 

 plant , much used for 

 baskets and for cov- 

 ering the ground un- 

 derneath benches. 



Differs from 

 Tradescantia 

 chiefly in the fact 

 that the corolla is 

 tubular (petals not 

 free) ; stamens 6, 



4058. Cross-section of ear of 

 busk corn. (XH) 



40-39. Zea r^nina, showing the long 

 branches, with ears at the joints. 



224 



