EXPERIMENT STATION REPORT. 453 



:short duration. The dodder root has no means of penetrating the 

 soil, and at best is only slightly and temporarily fastened to the soil. 



The stem lies coiled up in the dodder seed, and, with moisture, air 

 and heat added, the coats burst irregularly, the root tip protrudes, 

 and finally the stem, like a coiled watch-spring, is pulled out by 

 means of an upright " loop," that constantly elongates until the tip 

 is free, it having, in the meantime, absorbed the large stock of 

 endosperm that was packed around the embryo. The iodine test 

 shows that the young stem, as it is being extracted from the seed- 

 coats, is gorged with starch, the amount gradually diminishing as 

 the root end is approached. The root itself contains very little starch, 

 save in certain cells near to its tip. 



Usually, a short distance from the end of the slender stem, there is 

 a peculiar notch, that may be considered as locating a rudimentary 

 leaf. The tip is also irregular, but there are none of the well-recog- 

 nized elements of a formed bud. 



Through the root and the stem extends a central cord of fibrous 

 tissue, easily distinguished from the parenchyma of the main por- 

 tion, that surrounds it equally on all sides. It is unbranched, and 

 more of the nature of a tendril of squash than an ordinar)'- stem. 



Plate XII. shows various stages in the germination of the dodder 

 plants, all selected from seedlings that were between four and 

 ten days old. The sharp-pointed nature of the young roots, as they 

 first come from the ruptured seed-coats, is shown in the younger 

 specimens at the right and left sides, while the long, slender stem 

 above the somewhat larger root portion is shown in the more central 

 specimens. The peculiar "loop " near the small stem end is seen in 

 some of the other seedlings. Often the seed-coats are carried up at 

 this bend, and may be moved through circles described by the rotat- 

 ing stem, that very early develops the tendency to seek some object 

 of support. 



By growing the dodder seedlings upon soil covered with lamp- 

 black, it was possible to photograph these nearly white stems. That 

 they are much influenced by light was determined by growing the 

 young plants in saucers, so placed that one side only received the 

 light through a small hole in the dark chamber. 



The dodder was cultivated in the greenhouse upon several host 

 plants, the most interesting of which was that upon the buckwhe-at. 

 Seeds of a species Casciita Polygonornni Eng., found abundantly upon 

 smartweeds in the neighboring low grounds, were sown along with 

 •>the buckwheat, in pots. The above species was selected because its 



