ON THE VARIATIONS OF THE EVENING PRIMROSE 361 



style being 20 to 37 millim., that of the filament 16 to 22 millim. 

 In the smaller flowers (petals 20 to 30 millim.) the pistil is usually 

 either as long as or shorter than the stamens, but there are ex- 

 ceptions (Nos. 21, 24, 25, 32, 36) ; the range of variation is 4 to 

 20 millim. for the style, 10 to 15 millim. for the filament. The 

 tube is also generally shorter in proportion in the larger flowers 

 than in the smaller ones, just as in the typical CE. biennis, but 

 there is nothing absolute in this character." 



Taking the flowers alone, there is a complete and continuous 

 passage between CE. biennis and CE. Lamarckiana, and the series 

 before me shows the impossibility of distinguishing the two forms 

 on the relative length of the pistil and stamens, as has been pro- 

 posed by De Vries. 



I may add that I have compared some of the above flowers with 

 the examples of CE. biennis and CE. Lamarckiana received from 

 Prof. De Vries, without being able to detect any difference beyond 

 a greater length of the tube in the latter. 



The ripe seed-capsules vary greatly in size, form, and colora- 

 tion.! In the large-flowered specimens (Nos. 2, 6, and 8) they 

 measure 25 to 32 millim. in length, and 7 or 8 millim. in diameter, 

 and (as in CE. rubrineruis of De Vries) they are handsomely striped 

 with red. In No. 1 the fruit is narrower and shows no red. In 

 No. 35 the ripe capsule measures 31 by 6 millim., and is striped 

 with reddish. The largest capsules (42 by 7 millim.) are found in 

 No. 38, and they are striped with reddish. The shortest capsules 

 (23 by 7 millim.) are found in No. 19 ; there is no red on them. 

 But here again I have found these different types connected by 

 all possible gradations. 



Strongly puckered or crumpled leaves (as in CE. oblonga of 

 De Vries) often occur (Nos. 8, 24, 35), irrespective of the appear- 

 ance of the flowers. No form can be defined by the presence or 

 absence of crimson or pink in the stalks or the midribs of the 

 leaves, which is independent of its presence or absence in the 

 seed-capsules, and varies irrespective of the size of the flowers. 

 Some plants are remarkable for the long and narrow shape of the 



<E. Lamarckiana from the Botanic Garden of Amsterdam, for which I am indebted 

 to Prof. De Vries : — 



A. B. C. D. 



84 24 19 35 



29 18 16 29 



* Something similar obtains in the heterodistyled Primula elatior, as my 

 lamented friend L. Errera has shown (Rec. Inst. Bot. Bruxelles, vi. 1905, p. 225) 

 that the expanded part of the corolla is generally a little larger and the tube 

 shorter in the same proportion, in the macrostyled specimens ; this excess in 

 the diameter of the corolla is coupled with a slight increase in ihe intensity of 

 the coloration. As pointed out by Darwin (Different Forms of Flower $ 9 p. 49), 

 several heterostyled species when cultivated are apt to become homostyled; but 

 amongst the varieties of Auriculas distributed by florists, the long-styled form 

 is rare, as it is not valued, which seems to show that the fact observed by 

 Errera is not of general application in the genus Primula. 



t In the South Kensington specimens of CE. biennis, their length varies 

 between 24 and 31 millim., and their greatest diameter between 6 and 7 millim. ; 

 they are never striped with red. 



