440 Miscellaneous. 



On the Organogeny of the Irregular Corollas. By F. Barneoud. 



In the memoir which I have the honour of submitting to the Aca- 

 demy, I have described the results of further researches on the orga- 

 nogeny of the irregular corollas. I shall briefly indicate the principle 

 in this abstract. In the monocotyledons the study of the develop- 

 ment of the flower of the Cannece afforded direct proof that it is the 

 stamina only metamorphosed into petals in a more or less complete 

 manner from their first appearance, which impart to the corolla its 

 irregular aspect. The two outer ternary verticils are always deve- 

 loped one after the other, precisely as the calyx and corolla of dico- 

 tyledons. This law, which I have verified in more than ten families, 

 appears to be very general among monocotyledonous plants. In the 

 dicotyledons the adult corolla of the Acanthacece, Globularice, Gesne- 

 riacea, Bignoniacete and Goodeniacece, which is frequently far from re- 

 gular, presents itself on its first appearance in the form of a small 

 cupule with five very equal and rounded teeth at the border, but 

 this state is more or less ephemeral according to the genera and spe- 

 cies. Very soon the unequal elongation of the divisions of the co- 

 rolla, their different degrees of adhesion or their partial atrophy, 

 determine a very marked irregularity. The same applies with respect 

 to the flower of Centranthus in the Valerianae, to that of the Lobe- 

 liacete and of the Scrophulariaceee. In this last family the corolla of the 

 Calceolaria, one of the most anomalous of the vegetable kingdom, is 

 reduced at its origin to a scooped-out cupola, which is very regular 

 and furnished with four equal minute teeth ; the nascent calyx like- 

 wise presents but four divisions. 



The highly remarkable floral envelope of Begoniacea likewise ap- 

 pears at the period of its formation, as regards both male and female 

 flowers, in the form of a continuous ring, and exhibits at its cir- 

 cumference five very equal small segments ; but there are some of 

 them, especially in the male flowers, which disappear entirely or 

 which become in part atrophied, so as to give to the coloured enve- 

 lope that peculiar structure which forms its principal character. 



From the facts detailed in my two memoirs and derived from the 

 study of genera with irregular flowers from twenty-five natural fami- 

 lies, I feel justified in deducing the following consequences : — 



1. The simple theory announced by DeCandolle as early as 1813, 

 according to which the irregular flowers should be referred to regular 

 types from which they appear to have degenerated, must be admitted 

 as true, although conceived d, priori, and solely from the attentive 

 examination of some cases of peloria, or of flowers which have become 

 regular at the adult age. But if in the actual state of science, orga- 

 nogeny affords us a direct demonstration of this important principle 

 of botanical philosophy, I must add, that the symmetry of an irregular 

 flower even at its very origin does not always strictly exist ; it is fre- 



iranslation appeared in the ' Annals of Natural History,' vol. xi. 1843. The 

 memoir chiefly details the mode in which the leaf is fastened into a spiral 

 coil by the larva. The author was unaware to what species or genus it 

 belonged. 



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