316 ORSEUVATIONS ON PROTANDRY AND I'ROTOGYNY. 



of tlie stamens before the pistils, in the other case the development of 

 the pistil before the stamens, are so convenient and expressive that I 

 have adopted tliem in this paper ; the term by which he expresses that 

 the two organs are matured simultaneously, " Non-dichogamy," does 

 not seem to me so happy, and I propose to substitute for it Synacmy, 

 — the phenomena of Prolandry and Frotocjyny forming together thait of 

 Heteracmy. 



The following observations must be understood as referring simply 

 to the fact of the relative times at which the reproductive organs arrive 

 at maturity, as shown by the discharge of tlie pollen from the anthers 

 and the appearance of the viscous or papillose surface on the stigma, 

 or other evidence of readiness for the reception of pollen ; they have 

 not been further confirmed by the dissection of the st_vle and detection 

 of pollen-tubes, which would have occupied more time than I had at 

 my disposal. The plants observed are all British, growing in their 

 native habitats, nearly all common plants, or at all events easily at- 

 tainable, and the parts so conspicuous as to render observation of 

 the phenomena described accessible to any one with a microscope of 

 comparatively low power, in many cases with the naked eye. The 

 classification and specific names used are those of Dr. Hooker's 

 * Student's Flora.' The time of observation was between August 1st 

 and September 2nd. Several important Orders and classes, as TJni- 

 beUifer(P, Composites, ApetalcE, and Graminea, have been entirely passed 



I should premise that my observations do not confirm the inference 

 that may be drawn from the remarks of previous observers, tbat, in 

 heteracmic plants, the diff'erence in the time of maturity of the two 

 organs is so great as to render self-fertilization impossible. This I 

 find to be seldom the case ; generally, in heteracmic plants, the period of 

 maturity of one organ to a certain extent overlaps that of the other, so 

 that self-fertilization is not so much rendered impossible as cross-fertili- 

 zation is facilitated. In synacmic plants, on the other hand, the period 

 of maturity of one organ may frequently exceed in length that of the 

 other, so as to render cross-fertilization easy. Hence no absolute line 

 can be drawn between the plants indicated in the three subjoined 

 lists ; further observations may, in a few cases, cause the transference 

 of a species from one to another. 



