REPRODUCTIVE ORGANS IN THE PRIMULACE X. 103 
mutual action, might certainly suffice to show that sterility is not 
a special endowment, but a necessary result of secondary causes, 
which have no connexion whatever with special ends in the de- 
velopment of the classifying principle. 
With my experiments in crossing P. vulgaris with P. veris I 
was most unfortunate ; all my experimental plants met with an 
accident, and thus provokingly disappointed me of the results of 
my work. But for the kindness of Mr. Darwin, who, when I 
made him aware of my misfortune, obligingly sent me the 
following table, comprising the results of his experiments on the 
crossing of these species, I should have been entirely unable to 
illustrate this important part of my subject. With the exception, 
then, of the two first unions (the few results derived from my 
own experiments), all the others in the following table have been 
afforded me by Mr. Darwin. 
Taste VI.—Cross-unions of Primroses, Cowslips, and 
Polyanthuses. 
Fa [Spo d ed 
m | » EK) lation. | 
E IS KEEN j | 
5 P 9 Sg d 
a INESCEER 
S¥eEg| 3 28 2 |S 
i353 E bele Be 
Bb5sSs| g 1838/3 18 3] 
Seo Sl 3 Sur See 
e i LS LG 
ud ae e EE 
Long-styled Cowslip by pollen of Primrose : | 
LE 8 | 3 | 33 | 11 | 50 | 550 
Heteromorphic umon- ed EEN 8s 0. 0| 0 
Long-styled Primrose by pollen of Cowslip : | | | 
Honmonorplie union s.s. ener 3| 220 | 10 | 50 | 500 
Heteromorphic ubion..,... ..... eee ene 3| 01 0: 0 
Long-styled Primrose by pollen of Polyanthus : | | | 
Homomorphic NNN EE 5| 01 ol 0 
Heteromorphic unten... +. 5, 2/53 26 | 50 |1325 
Short-styled Primrose by pollen of Cowslip : | | | 
Homomorphio mon 5, 6.6... eire 3; 0 0! 0| 
Heteromorphic union........................ se 3| 3142 | 47 | 50 2366 
Short-styled Primrose by pollen of Polyanthus : | | | 
Homcomorphié (nion ...... 5 e rers crure | 4| 2 | 32 16 | 60 | 800 
Heteromorphie union.,......<..cc0s<ssveoseosss oo I | 28 | 28 | 50 |1400 
The results of certain unions in this table are most interesting 
in their bearings on the general phenomena of sterility, and par- 
ticularly from the excellent illustrations they afford of the extra- 
ordinary complexity of the laws of hybridism. We shall best 
appreciate their bearings on these phenomena, howeyer, by the 
