THE STUDY OP THE EVOLUTION OP THE FLOWEE. . 307 



Fig. 28. H. ruscifoHa. Young female inflorescence. 

 Fig. ^9. H. rusdfolia. Young female flower- 

 Fig. 30. H, ruscifolia. Mature flower, pentamerous. 



Fig. 31. H, ruscifolia. Flower with four perianth-leaves and five carpels. 

 Fig. 33. H. ruscifolia. Tetramerous ^ower. 

 Fig, 33. Corohia Cotoneaster. Young flower. 

 Fig, 34. C, Cotoneaster. Mature flower. 

 Fis:. 35. GnseUnia lucida* Youu^: male flower. 



» 



D 



Fig. 36, G. lucidan Hexamerous male flower^ side view. 



Fig. 37. G. lucrda. Hexamerous male flower, viewed from above. 



L 



Fig. 38, G. litloralis, Male flower, closed. 



Fig. 39. G. littoralis. Male flower, open. 



Fig. 40. G. lucida. Very young female flower, highly magnified. 



Fig. 41. G. luc'ida. An older stage. 



Fig. 42, G, lucida. Mature flower. 



Fiir. 43. G- lucida. Fruit, 



Fig. 44. G. littoralis. Young female flower 



Fier. 45. G. lit tor alls. Mature flower. 



to 



Fig. 46. G. littoralis. Young fruit. 

 Fig. 47. G. littoraHs. Older fruit. 



Fig. 48. JS^yssa sylvatlca. Portion of a young inflorescence- 

 Fig. 49. N. syhatica. Young flower. 

 Fig, 50. N. sfjlvatica. Young flower with petals removed to show the single stamen present in this 



specimen 



Plate 29. 



[Abbreviations :—arch. = archesporium ; ant. = antipodals ; ax. = axial row ; e. sac. = embryo-sac ; 



/. = loculus; 2/if. = integumeut; m.^micropyle ; m. 5/>. = megaspore; n. ep. = epidermis of nucellu^*: 



/?Gr. = parietal tissue.] 



Figs. 51-54. SympJioricarpus raccmosus. Development of sporogenous tissue in sterile ovules. 51, 



primary arcliesporlal cell; 52, two sporogenous cells; 53, four sporogenous cells; 54, one 

 of four raegaspores lias germinated to form an incomplete embryo-sac. x600 approx. 



Figs. 55-57. Viburnum Lantana. Development of the megaspores in the incomplete ovules. 55, 



primary archesporiul cell; 56, hinucleate sporogenous cell ; 57, quadrinucleate sporogenous 



cell. X 600 approx. 

 Figs. 58-63. V. Lantana. Further development of the sporogenous tissue in the incomplete ovules. 



58, portion of multinucleate protoplasmic sac showing e^ght of the twelve nuclei ; 59, nuclei 



approximated in pairs ; 60, segmented protoplasmic sac. x COO approx. 

 Fig. 61. Sambucus niyra. Vertical section through a young ovule, showing single 



nucellus with primary archesporial cell. X 290 approx. 

 Fig. 63. S. nigra. Section through an ovular rudiment showing the enlarged subepidermal cells- 



X 590 approx. 

 Figs. 63-64. ^. nijra. The nucleus in the enlarged cells has divided to form i^KO or four daughter 



nuclei, x 590 approx. 

 Fig. 65. Benthamia fragifera. Vertical section of a young ovule showing an early stage in the 



upgrowth of the single integument. X290 approx. 



Fig. 63. B. frngtftra. Vertical section of a young ovule, showing the nuceUus with axial rows. 



X 290 approx. 



integument 



