125 



VEGETABLE LIFE AND WORK. 



[SECTION 16. 



Accumhent, that is, the edges of the flat cotyledons lie against tlie radicle, 

 as in Fig. 425, 426. In another they are 



Incumbent, or with the plane of the cotyledons brought up in the opposite 

 direction, so that the back of one of them lies against 

 the radicle, as shown in Fig. 427, 428. 



391. As to the situation of the embryo with respect 



to the albumen of the seed, when this is present in any 



quantity, the embryo may be Axile, that is occupying 



tlie axis or centre, either for most of its length, as in 



Violet (Fig. 429), Burberry i^'xg. 4S), and 



Pine (Fig. 56) ; and in these it is straight. 



But it may be variously curved or coiled 



in the albumen, as in Helianthemum (il 111 11 



(Fig. 430), in a Potato-seed (Fig. 50), 



or Onion-seed (Fig. 60), and Linden 



(Fig. 414) ; or it may be coiled around 499 430 



the outside of the albumen, partly or into a circle, as in Chickweed (Fig. 



431, 432) and in Mirabilis (Fig. 52). The latter mode prevails in Cumpylo- 



jffr^?^ z^**"^!^ tropous seeds. In the cereal grains, such as Indian 



^; ^'-oM /, '"'^yj^, Corn (Fig. 67) and Rice, 430 «), and in all other 



^^^■^^ x^ c/'' Grasses, tlie embryo is straight and apjilied to the 



431 432 outside of the abundant albumen. 



392. The matured seed, with embryo ready to germinate and reproduce 



the kind, completes the cycle of the vegetable life in a phanerogamous 



plant, the account of which began with the seed and seedling 



Section XVI. VEGETABLE LIFE AND WORK. 



393. The following simple outlines of the anatomy and physiology 01 

 plants (3) are added to the preceding structural part for the better prepar- 

 ation of students in descriptive and systematic botany ; also to give to all 

 learners some general idea of the life, growth, intimate structure, and action 

 of the beings which compose so large a part of organic nature. Those who 

 would extend and verify the facts and principles here outlined will use the 

 Physiological Botany of the " Botanical Text Book," by Professor Goodale, 

 or some similar book. 



Fig. 427. Seed of a Sisj-mbrium, cut across to show llie incumbent cotyledoijs. 

 428. Eiiibrj'O of the same, detached whole. 



Fig, 429. Section of seed of Violet ; anatropous witli straight axile embryo in 

 the albumen. 430. Section of seed of Rock Rose, Helianthemum Canadense ; 

 orthotropous, with curved embryo in the albumen. 430". Section of a grain of 

 Rice, lengthwise, showing the embryo outside the albumen, which forms the 

 principal bulk. 



Fig. 431. Seed of a Chickweed, campylotropous. 432. Section of same, show 

 ing slender enibrvo coiled around the outside of the albumen of the kernel. 



