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BOTANY AND PHARMACOGNOSY. 



a nucellus (megasporangium), being that portion next within the 

 integument ; and embedded within the nucellus a portion known 

 as the megaspore or embryo-sac. 



Fig. so. Development of gametophyte and embryo in one of the Coniferas. e, 

 embryo-sac (megaspore); a, archegonium; h, neck of archegonium; i, integument; p^ 

 pollen tube; n, nucellus; f, wing of seed; g, fibrovascular tissue; kz, canal cells of arche- 

 gonium; ka, beginning of embryo; k, nuclei; ws, tip of root; wh, root-cap; c, cotyledons; 

 V, point of growth of stem; s, suspensor. 



I, early stages of embryo-sac (e); II, young archegonium (a) after development of 

 neck cells (h), cell lumen (1); III, section of ovule with portion of attached seminiferous 

 scale(f) showing entrance of pollen tube; IV, embryo-sac with two developed archegonia; 

 V, archegonium after fertilization there being four nuclei at the lower part only two of which 

 are seen; VI, further development of embryo; VII, VIII, IX, X, showing development 

 of large tortuous suspensor, to which is attached the young embryo (ka); XI, XII, mature 

 embryo. — ^After Strasburger. 



