Butters: seeds and seedling of caulophyllum, 25 



season it has completely absorbed the endosperm. It then withers 

 away together with the petioles of the cotyledons, and no trace of the 

 seed is to be found at the beginning of the next season (PI. VII). 



Fed by the large amount of nutriment absorbed from the endo- 

 sperm by the haustorium, the hypocotyl rapidly elongates and gives 

 rise to the rather stout primary root (PL VI). This grows down- 

 ward in a somewhat irregular course, and by the end of the season 

 has usually a length of about 12 cm. Its diameter is i. 0-1.5 "^"i- 

 By the time the primary root is 8 cm. long, lateral roots begin to 

 grow out from it, the first appearing about i cm. below the attach- 

 ment of the cotyledons, and later others farther down. These lat- 

 eral roots have about one-half the diameter of the primary root. By 

 the end of the season several of them may attain a length of over 

 2 cm. 



In contrast to this rapid development of an efficient root system, 

 the epicotyl grows very slowly. During the first season the stem 

 axis elongates very little, and usually no foliage leaves are pro- 

 duced, but only about five scale-leaves which grow up over the tip 

 of the axis forming one of the typical winter buds of the plant. 

 Within this bud are produced the primordia of the foliage leaves of 

 the next season's growth, and in the axils of the cotyledons, and of 

 the bud scales may already be distinguished the primordia of the 

 first lateral branches of the stem. It is thus seen that the first sea- 

 son's extra-seminal growth of the seedling may be entirely hypoge- 

 an, and it seems probable that under natural conditions it is always 

 so. Of seedlings started in the hot-house during the winter a very 

 few (less than 10 per cent, of the total number) produced a small 

 foliage leaf during the latter part of the following summer. In 

 these cases the foliage leaf took the place of the first of the bud 

 scales which are usually produced, and a very small winter bud was 

 formed at its base (Fig. 2;^, PI. VI). 



Later Development of Seedling. 



The second year's extra-seminal growth (PI. VII) does not 

 differ essentially from that during the several following years. A 

 foliage leaf appears above ground in the early spring, and a few 

 weeks later it is followed by another. They persist throughout the 

 summer. Above these several scale leaves are produced which 

 form the scales of the next winter bud. The foliage leaves for 

 several seasons are usually simply trifoliolate. 



