128 



VEGETABLE LIFE AND WORK. [silCTION IG. 



Accumlfnt, that is, the edges of tlie Hat cot^leduus lie agaiust llie radicle, 

 as ill Fig 425, 420. In auotlier they are 



lacumbenl, or with the j)Iaue ot the cotyledons brought up iu the opposite 

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

 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 



428 the axis or centre, either for most of its lengtli, as in 



Violet (Fig. 429), Barberry (Fig. 4S), and 



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



But it nuiy be variously curved or coiled 



iu the albumen, as in Heliauthemum 



(Fig. 430), in a Potato-seed (Fig. 50), ^I'll^ (|(Q)J 

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



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



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

 431, 4;i2j and in Mirabilis (Fig. 52). The latter mode prevails in Campylo- 

 tropous seeds. In the cereal grains, such as Indian 

 1*1 Corn (Fig. 67) and Rice, 4o0"), and in all other 

 _^^' Grasses, the embryo is straight and applied to the 

 431 432 outside of the abundant albumen. 



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

 the kind, coinpletes 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 of 

 plants (3) are added to tbe 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, intunate structure, and action 

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

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

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

 or some similar hook. 



Fig. 427. Seed of a Si.symlinum, cut across to sliow the incumbent cotyledons. 

 428. Embr5'o of the same, detarlieil whole. 



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

 the albumen. 4.30. Section of seed of Rock Rose, Helianthemuin 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. Soeil of ;i Chickweed, campylntinjions. •J32. .Section of same, show- 

 ing slender embryo coiled around the outside ot the albumen of the kernel. 



