109 



PLATE XXV. Pinus Laricio. A. 1, Branch with leaves and 

 terminal bud ( x 1) ; 2, Male flower ( x 54) ; 3, Longitudinal 

 section of same ( x 38) ; 4, Detached stamen ( x 100) ; 5, 

 Longitudinal section of a staminal leaf ( x 88) ; 6, Dry pollen 

 grains ( x 300) ; 7, Optical section of a ripe pollen grain ( x 2000) ; 

 8, Germinating pollen grain ( x 2000). 



PLATE XXVI. Pinus Laricio. B. 1, Three stages in the 

 development of the female cone ( x 1) ; 2, Longitudinal section 

 of a ripe female cone ( x 40) ; 3, View of a ripe female cone 

 ( x 21) ; 4, Upper side of a fruit scale ( x 37) ; 5, Ovule 

 ( x 300) ; 6, Ripe cone ( x 4 -5) ; 7, Ripe seed ( x 8). 



PLATE XXVII. Pinus Laricio. C. 1, Half -grown cone one year 

 old ( x 2) ; 2, Longitudinal section of the same ( x 2) ; 3, Longi- 

 tudinal section of the unfertilised ovule ( x 140) ; 4, Upper part 

 of an unfertilised archegonium (x 370); 5, The same at the 

 moment of fertilisation ( x 370) ; 6, Ovum after fertilisation 

 ( x 285) ; 7-9, Development of rudimentary embryos and 

 suspensors (x 150 and 240). 



PLATE XXVIII. Elodea canadensis. 1, Flowering specimen 

 ( x 1) ; 2, Part of stern with three whorls of leaves ( x 8) ; 

 3, Female flower ( x 23) ; 4, Upper surface of leaf ( x 2200). 



PLATE XXIX. Erythrotis Beddomei (Cyanotis Kewensis.) 

 1, Flowering branch ( x 1) ; 2, Inflorescence ( x 13'5) ; 3, Stamen 

 (x 31); 4, Staminal hair ( x 300); 5, Upper end of a young 

 staminal hair ( x 7320) ; 6, A similar one further developed 

 ( x 7320) ; 7, Single mature cell of the staminal hair ( x 4400). 



PLATE XXX. Cuscuta glomerata. 1 , a, 6, Plant attached to 

 Aster bessarabicus ( x 1) ; 2, Flowering shoot ( x 5) ; 3, Trans- 

 verse section of Solidago Muhlenbergii with Cuscuta attached 

 (x 63); 4, Inflorescence of Cuscuta (x 17); 5, Section of a 

 flower in the first stage ( x 17) ; 6, Side view of a flower in the 

 second stage ( x 17) ; 7, Young fruit ( x 17). 



PLATE XXXI. Lavatera trimestris. la, Flowering branch 

 (x 1); 16, Flower commencing to open (x 2'5) ; Ic, Flower 

 bud ( x 9*5) ; 2, Staminal whorl and apex of floral axis ( x 360) ; 

 3, Anther ( x 1725) ; 4, Anther in longitudinal section ( x 1725) ; 

 5, Anther somewhat more developed ( x 1725) ; 6, Pollen 

 mother-cells ( x 1725) ; 7, Isolated pollen mother-cell ( x 1725) ; 



8, Part of another lobe with two such cells ( x 1725). 



PLATE XXXII. Lavatera trimestris. 1, 2, Isolated pollen 

 mother-cells ( x 1725) ; 3, Young anther with filament and 

 pollen grains ( x 120) ; 4, Anther somewhat younger ( x 150) ; 

 5, Stamens with pollen escaping ( x 25) ; 6, Transverse section 

 of anther ( x 1000) ; 7, Sexual apparatus of the flower in the 

 second or female stage ( x 9) ; 8, Fragment of the style ( x 350) ; 



9, Pollen grains ( x 120) ; 10, Pollen grain ( x 435). 



PLATE XXXIII. Lilium Martagon. A. 1, Plant in flower 

 ( x 1) ; 2, Diagram of the flower ( x 10) ; 3, View of the flower, 



o G798G. H 



