Vol. XXIII. No. 2.] 



POPULAR SCIENCE NEWS. 



23 



treeless hillside, and the influence of wind as an im- 

 portant element of their environment is evident in 

 manj peculiarities of their structure. With maize 

 these peculiarities are especially well marked for we 

 can see in almost every part, either provisions 

 against injury from wind or means of utilizing its 

 powers of transportation. 



In such a tall plant as maize there is especial use 

 for means of resistance in high winds, and this is 

 afforded by strong "brace-roots" (B. R. Fig. i) 

 which emerge from the lower joints of the stem, 

 and extending obliquely downward fasten them- 

 gclves firmly in the earth. These brace-roots 

 would, however, be of little avail were it not for 

 the diminution of strain which is secured by the 

 yielding of the elastic stem, and the supple, elon- 

 gated leaves. 



Besides the danger that comes from the force 

 of the wind, there is the liability to injury from 

 its drying effect when combined with direct 

 exposure to the sun. Any way of decreasing the 

 exposed surface lessens, of course, the evapora- 

 tion, and in maize this is accomplished by means 

 of longitudinal bands of hygroscopic tissue as 

 disposed on the upper surface of the blade, so 

 that in dry air they contract, the halves of the 

 blade fold together and the edges roll inwards. 

 At the return of moisture, by a reverse action 

 of the hygroscopic tissue, the blade becomes 

 flat as before. 



Passing now to the ways in which our plant 

 makes use of the wind, we have first to consider 

 the means of securing cross-fertilization. It is 

 well known that the formation of seeds takes 

 place only after pollen has reached the stigmas 

 and exerted its fertilizing effect upon the ovules, 

 and that seeds which arise as a result of fertili- 

 zation by pollen from another plant of the same 

 kind produce so much better offspring than 

 seeds fertilized by pollen from the same plant, 

 that it becomes highly important that cross- 

 fertilization should be secured. 



In those plants that depend upon insects for 

 the transference of their pollen, we find, as a 

 rule, conspicuous flowers, attractive odors, nectar, 

 and a comparatively small amount of pollen ; 

 while on the other hand, plants that utilize the 

 wind as a carrying agent, have inconspicuous 

 flowers, and neither fragrance nor nectar, but an 

 abundance of pollen to compensate ibr the 

 necessitated waste. 



There can be no doubt as to which of these classes : 



maize belongs. High up in the air the staminate 

 '" 1 



flowers hang out their pollen sacs on slender threads 



that quiver at the slightest breath and shake the 

 pollen-dust at every passing breeze. Once in the i 

 air the pollen sinks with more or less obliquity, 

 until reaching the level of the tasseled ears of some 

 plant it settles upon the silky stigmas. When we 

 come to examine these stigmas closely, we find that 

 they are not the simple threads they appear to be at 

 first sight, but are covered with delicate hairs (ST., 

 Fig. 3) which are obviously for the purpose of hold- 

 ing the light pollen grains. 



After the series of changes induced by fertiliza- 

 tion have culminated in the ripened fruit, the next 

 thing for a plant to accomplish is the sowing of its 

 seeds. With maize, as we have seen, the work has 

 been performed for ages by man, and there being 

 no need of any provision for dissemination on the 

 part of the plant, it is not surprising that the spe- 

 cies should have lived on, generation after genera- 

 tion, from prehistoric times, with its grains fastened 

 tightly to the cob and closely wrapped about by 

 husks. It is hardly possible to believe, however, 

 that in the wild state such a condition of things 

 could long endure, and we are forced to assume that 



before the time of cultivation, the maize fruit dif- 

 fered in important particulars from the form we have 

 today. 



Without an examination of actual specimens of 

 wild maize we can, of course, never be sure just 

 how much the ancestral plant differs from its mod- 

 ern descendant ; nevertheless, a consideration of 

 such evidence upon the subject as we do possess, 

 enables us to form a mental picture of the original 

 form which is probably not far from the truth. 



In the region of Central America — the old home 

 of our Indian corn — there grows today a plant 

 called 'teosinte" (Eiichltrna Mexicana, Schrad.) 



Fijj. I. Kiitiro iiiaizc-pliint (micr Bonafims.) F. R., filirmis 

 roots; H. it , br:icc roots; S.,sfieatli; B., blade; L., lij^ule; M., 

 male (stainiiiatc; ilowuis; 1'., fcitiule (pistillate) flowers. 



which being the nearest known relative of maize, is 

 of especial interest in our present inquiry, since 



from what we know of the laws of inheritance we 

 may fairly assume that characteristics which in 

 maize have been lost during cultivation, have in its 

 wild relative been retained through the conservative 

 influence of natural surroundings, and so handed 

 down but little changed from the common ancestor. 

 Teosinte resembles maize very closely in its gen- 

 eral appearance ; the stem and leaves of both are 

 quite similar; there is in teosinte a terminal tuft of 

 staminate spikes very much like that of maize even 

 to minute particulars; and there are pistillate flow- 

 ers with long styles projecting beyond an envelop- 

 ing sheath. These characteristics, it should be ob- 

 served, are the very ones which 

 would be the least affected by cul- 

 tivation, and it is significant that 

 when we turn to the points of 

 difference we find them most im- 

 portant in what relates to the fruit. 

 In the first place, teosinte does 

 not have its pistillate flower;- 

 massed together on a thick spike j 

 or ear, as in maize, but has in 

 place of this a cluster of slender 

 spikes on which the flowers arc 

 arranged in two rows. Except for 

 the fact that the individual flowers 

 are each enwrapped by lateral 

 outgrowths of the axis, they are 

 essentially similar to those of 

 maize. Finally in the ripened 

 fruit there is the provision for dis- 

 semination which we found to be 

 entirely lacking in maize. 



As soon as the grains are mature 

 the axis on which they are borne, 

 breaks into joints — one joint to a 

 grain — and the grains each sur- 

 rounded by the protecting glumes 

 and the joint of axis, are loose 



-Sm 



-Sy. 



-Ov 



in the hollow sheath like so many F'.K: 3- Pistil- 



seeds in a capsule. Being thus 

 situated they are ready for the 

 last kind offices of the wind. A 



Fig. 2. Staminate flowers, maguified (after Nees) ; G., glumes 

 ,, anttiers. 



late flowers, 

 one-lialf natu- 

 ral size (after 

 Bo nafo us) ; 

 Ov., ovary; 



,.,.,, . Sy. , style; Sm. 



light wind, however, is not enough stigma. 



to carry such heavy grains more than a little 

 way, and it is obviously desirable to shield 

 the grains from a carrier so insignificant. 

 This is so well accomplished by the enveloping 

 sheath, that an ordinary breeze can only rattle 

 the grains within it, but let a strong wind come 

 up and they are shaken out with ease and carried 

 to a good distance from the parent. 



Now the question comes : Have we any traces in 

 the maize ear of its having been developed from a 

 cluster of branches like that of teosinte .' Several 

 facts assuredly point in this direction. If several 

 branches, each having two rows of flowers, should 

 coalesce, we should expect to find that the resulting 

 spikes must have an even 

 number of rows, and this 

 we do find to be always the 

 case in the maize ear, and 

 very often the rows are 

 obviously in pairs. Add to \ 

 this the fact that ears of 

 corn with one or more 

 branches are not at all un- 

 common, and we have a 



line of evidence nicelv cor- ^- ,,■ ,.„ , „ 



rig. 4. I istillati' l!o\ver,mag- 



roborating our original nifieii (after .\ees); G., 

 . . glumes,ll somewhat spread 



supposition of a teosinte- apart; Sy., ha.se of style. 



like ancestor for maize. 



The further question as to how the compact maize- 

 ear could have been developed from a cluster of 

 branches, is one upon which we are at a loss for 

 facts. Whether the tendency for the branches to 



