488 MR. M. T. MASTERS ON AXILLARY PROLIFICATION IN FLOWERS. 



In the Dimitlms (PI. LIV. fig. 1), tlie adventitious growth occurred in the form of a 

 circle of flower -stalks bearing alternate, strap-shaped, petal-like scales and one or two 

 imperfect flower-buds, which were made up externally of leafy or petal-like scales, within 

 which was a gamosepaloiTS calyx enclosing rudimentary petals, stamens, and carpels. In 

 other cases, the outer scales were like carpellary leaves destitute of ovules, their margins 

 widely separated one from the other, and their summits surmounted each by a style 

 nearly as long as the leaf itself. 



A comparison of the two forms of prolification, axillary and median, leads to some 

 interesting results, and enables me to mention a few circumstances that have occurred to 

 me since my former paper, on median prolification, was published, or that were omitted 

 or overlooked during its compilation. Axillary prolification is a much less frequent 

 malformation than the central form. If only the number of orders and genera be 

 reckoned, the truth of this statement wiU be scarcely recognized ; but if individual cases 

 could be estimated, the difference in this respect between the two would be very much 

 more obvious. This may perhaps be explained on the following grounds : — 



It is now almost universally admitted that the flower is homologous with the branch ; 

 that, up to a certain time, the branch-bud or leaf-bud and the flower-bud do not essen- 

 tially differ *. At a later stage, the difference between the two is manifested, not only 

 in the altered form of the lateral organs in the flower-bud, but in the tendency to an 

 arrest of growth in the length of the central axial portion. Now, in proHfied flowers, 

 the functions and to a considerable extent the appearance of a leaf-bud or of a branch 

 are assumed, and with them the tendency to grow in length. Median prolification, 

 therefore, in this sense, is a further step in retrograde metamorphosis than is the 

 axiUary form. To grow in length, and to produce axillary buds, are alike attributes 

 of the branch ; but the former is much more frequently called into play than the latter ; 

 for the same reason, median prolification is more common than the axillary form. 



The frequency with which " apostasis," or the separation of the floral whorls one from 

 another, to a greater degree than usual, is met with in prolified flowers has been before 

 aUuded to. 



In both forms, the adventitious growth is much more frequently a flower-bud or an 

 inflorescence than a leaf -bud or a branch. How this is to be accounted for I can only 

 conjecture. Perhaps it may be due to the position of the flowers on a portion of the 

 stem of the plant especially devoted to the formation of flower-buds to the more or less 

 complete exclusion of leaf-buds, i. e. the inflorescence. This is borne out by the com- 

 parative rarity with which prolification has been observed in flowers that are solitary in 

 the axils of the ordinary leaves of the plant. If the lists of genera be perused, it will 

 be seen that nearly aU the cases occur in genera where the inflorescence is distinctly 

 separated from the other branches of the stem. In direct proportion, then, to the 

 degree in which one region of the stem or branches of a plant is devoted to the for- 

 mation of flower-buds to the exclusion of leaf-buds, is the frequency with which those 

 flower-buds may become affected with floral prolification. 



* Linn. Prolepsis Plant. § vii. ; Goethe, op. cit. §§ 103-106. 



