10 



MORPHOLOGY 



20. Caulicle or Radicle, and Cotyledons. The name of radicle 



was early applied to tin- uxis of tin- embryo below the cotyledons, 

 on the supposition that it was the actual beginning of the root. 

 But its structure and mode of growth show it is not root (iM. 

 11. 7*), but a body of the exact nature of Mem. from the 

 naked end of which the root is developed. Wherefore ('iuiln.lt' 

 (Lat. canllcitluK, diminutive of mulis. stem) is 

 tin- appropriate name : and it would he gen- 

 erally adopted, wen' it not that the older term 

 is so incorporated into the language of sys- 

 tematic 1 iot any (in which fixity and uniformity 

 are of the utmost importance) that it is not 

 easily displaced. It may be continued in 

 descriptive botany on this account, but in 

 morphology it is apt to mislead ; and the name 

 of caulicle, suggestive of the true nature of 

 the organ, is preferable. 1 The more fanciful 

 name of Cotyledons was very early applied to 

 what are now recognized as answering to the 

 leaves of the embryo : it has the negative merit 

 of suggesting no misleading analogy. '- 



21. Development of the Dicotyledonous Em- 

 bryo, /. e. the two-leaved embryo. This, in 

 the Red Maple (Figs. 5-8), usually germinates 

 in summer, shortly after the fruits of the season 

 have matured and fallen to the ground. It 

 differs from that of Sugar Maple in the crump- 

 ling instead of coiling of the cotyledons in lin- 

 seed. Referring the whole physiology of ger- 

 mination to that part of the work which treats 

 Of Vegetable Physiology . the development of 

 the embryo into the seedling may hen- be described, taking that of 

 a .Maple fora convenient type or pattern, with which other forms 



1 Linnaeus called it Hoodlum, a nanu- which, bein"; etymological] v mean- 

 ingless in this connection, is not misleading. The French lioiani.-ts named it 

 Tii/ill'-, diminutive of ti<i< , stem: lint some (like Mirbel) applied the term to 

 the dc\ eloping axis above the cotyledons; others, to the early axis both 

 above and below them. The name /!<K//'<->I/<I originated with ( iaertner. 



- The name t '////, t/<i, which was adopted by I,inna-us, is a (ireek word 

 for a cup-shaped hollow or cavity, also for a plant with thickish and saiuvr- 

 shapcd leaves. It was primarily applied to the thickened " lobes " of the 

 embryo, the foliaccous nature of which was not recouni/ed. 



FIG. 5. One of tin- twin winded fruits of Red Miiplo (Acer rubrnm'l. with body 

 ilivii led, to show the see.1. )>. Seed extrnrled ami divided, to show the embryo within. 

 7. Embryo parti* 1 vuil'oldiMl. 8. Embryo in early sta^e of 



