24 



SEEDLINGS. 



lSECTION 5. 



two cotjledous eveu in a Piue-embryo, but these divided or split up con. 

 genitally so as to imitate a greater number. But as leaves are often m 

 whorls on ordinary stems, liiey may be so at tbe very beginning. 



40. Monocotyledonous (meaning with 

 single cotyledon) is tlie nume of the one-coty- 

 ledoned sort of embryo. This goes along 

 with peculiarities in stem, leaves, and flowers ; 

 which all together associate such i)lants into 

 a great class, called Monocotyledonous 

 Plants, or, for shortness, Monocotyls. It 

 means merely tiiat the leaves are alternate 

 from the very first. 



41. In Iris (Fig. 58, 59) the embryo in 

 the seed is a small cylinder at one end of the 

 mass of the albumen, with no apparent dis- 

 tinction of parts. The end which almost 

 touches the seed-coat is caulicle ; the other 

 end belongs to the solitary cotyledon. In 



germination the whole lengthens (but mainly the 

 cotyledon) only enough to push the proximate 

 end fairly out of the seed : from this end the root 

 is formed; and from a little higher the plumule 

 later emerges. It would appear, therefore, that 

 the cotyledon answers to a minute leaf rolled up, 

 and that a chink through which the plunmle 

 grows out is a part of the inrolled edges. The 

 embryo of Indian Corn shows these parts on a 

 larger scale and in a more open state (Fig. 66- 

 68). There, in the seed, the cotyledon remains, 

 imbibing nourishment from the softened albu- 

 men, and transmitting it to the growing root y, 59 

 below and new-forming leaves above. 



42. The general plan is the same in the Onion (Fig. 60-65), but with 

 a striking difference. The embryo is long, and coiled in the albumen of the 

 seed. To ordinary examination it shows no distinction of parts. But 

 germination plainly shows that all except the lower end of it is cotyledon. 

 For after it has lengthened into a long thread, the chink from which the 



Fio. 56. Section of a Pine-seed, showing its polycotyledonons embryo in the 

 centre of the albumen; moderately magnified. 57. Seedling of same, showing the 

 freshly expanded six cotyledons in a whorl, and the phminle ju.st appearing. 



Fig. 58. Section of a seed of the Iris, or Flower^le-Luce, enlarged, showing its 

 small embryo in the albumen, near the bottom. 59. A germinating seedling of the 

 same, its plumule developed into the first four leaves (alternate), the first one 

 nidimentary; the cotyledon remains in the seed. 



Fio. 60. Section of an Onion-seed, showing the slender and coiled embryo in the 

 albvimen : moueratelv magnified. 61. Seed of same in early germination. 



