April, 1922. 



SCIENTIFIC AGRICULTURE. 



261 



found very suitable." 



The stigma should now be carefully ex- 

 amined witli a lens to see if all pollen 

 has been cleared away; then any drops 

 of water adhering to any part of the flow- 

 er sliould be removed by the use of small 

 strips of thin blotting paper. It was also 

 found that the frayed edge of such paper 

 is very useful for brushing away anthers 

 or pollen grains which may not have been 

 removed by the Avater spray. Wlien a care- 

 ful inspection of the stigma shows that 

 it is quite clear and that all anthers and 

 pollen grains have been removed, cross- 

 pollination may be performed. 



At this time, the stigma is still held in 

 position by the piece of Timothy .stem 

 and is standing quite free from the stand- 

 ard (See fig. IIIc.) so that little difficulty 

 is experienced in pollinating the stigma. 

 The pollen may be collected on the flat- 

 tened end of a quill or a wooden toothpick 

 and transferred directly to the prepared 

 stigma of the female parent. The tootli- 

 pick is preferred to a camel hair brush as 

 it is more convenient to manipulate and 

 can much more ea.sily be cleaned or sterili- 

 zed for future use. 



A careful examination of the stigma 

 should noAv be made to make certain that 

 an abundance of healthy pollen is resting 

 on the stigma (care should be taken to 

 distinguish between pollen grains and 

 empty anther sacs). If found satisfactory, 

 the piece of Timothy stem may be re- 

 moved. In doing this, see that it is re- 

 moved at right angles to the sexual column 

 and in such a way as not to displace the 

 stigma or the adhering pollen. The re- 

 moval of this piece of Timothy stem al- 

 lows the process of tripping to continue 

 until it is completed. The pollen-covered 

 stigma then presses forward and comes in 

 close contact with the standard ; thus, tiie 

 pollen grains are entrapped and become 

 firmly attached to the face of the stigma : 

 thus completing tlie operation. 



After pollination, the flower is marked 

 by tying a piece of thread loosely around 

 the pedicel. In addition, a small tag is 

 attached to the base of the stem of the 

 flower cluster. On the tag is recorded 

 the parents used in making the cross, and 

 the date. The particulars as to male and 

 female parents, condition of weather, date, 

 and other essential information is record- 



ed on fiehl I'ei-oi-d slieets with special head- 

 ings for this purpose. The flower should 

 noAv be inclosed in a suitable manner so as 

 to protect it from the visits of insects and 

 to lessen- the risk of introducing ])ollen 

 from any outside source. 



After testing paper bags which did not 

 prove to be very suital)le as they were 

 easily broken or displaced during wind 

 storms, cages sufficiently large to inclose 

 a AvJiole plant Avere used. (Fig. IV.) 



Fig. IV. Method of protecting individual 

 plants. Clover species in foreground: Al- 

 falfa in background. 



These cages were made of ordinary Avire 

 netting — tAvo inch mesh — and covered 

 Avith cheese cloth : in size, tliey were about 

 tAvo and a half to three feet high and 

 about eighteen inches in diameter and 

 held in position over the plant by means 

 of Avooden stakes. It Avas found, hoAv- 

 ever, that the cheese cloth being somewhat 

 close in texture, it AA^as necessary to re- 

 move the cage directly after fertilization 

 had taken place : otherAvise the plant suf- 

 fered from being too closely confined. 

 In later experiments, mosquito muslin and 

 tarlatan Avere substituted for cheese cloth 

 Avith beneficial results. This method of 

 protecting, emasculating, and pollinating, 

 was practiced on a large number of floAv- 



