TRANSACTIONS OF THE SECTIONS. 69 
consequence of some remarks which fell from the several gentlemen named in that 
paper, at the time the specimens were observed, my attention was drawn to the sub- 
ject: the results I here offer in the shape of a few notes to explain the drawings*. 
To such as seek for illustrations of this branch of botanical inquiry, instances will 
rapidly accumulate from a large list of plants. Some genera however seem to present 
such changes more readily than others; and again, in some species of a genus they 
will be frequent, in others rarely, if ever, occur. Morphological changes are very 
common in Trifolium repens, occasional in Tr. pratense, but in this species they sel- 
dom extend beyond the calyx, whilst in Zr. incarnatum I have never yet detected an 
instance, though I have cultivated it for ssme years. 
Mr. Babington, in his ‘ Manual,’ after the description of T’r. repens, observes, ‘ that 
in damp seasons the pod is often protruded in the form of a horn, or changed into a 
small leaf.” This isan exact description of an appearance which the flower-heads fre- 
quently present, but the formations of pod or leaf seem to be exhibitions of contrary 
tendencies; in the one the plant hastens to accomplish its end, in the other it breaks 
away and reverts to the production of leaves. 
About the end of May in this year, the flowerets consisted of a calyx of the usual 
size; the petals and stamens were rudimentary, and the plant, as if passing over two 
stages of its flower-structure, proceeded directly to the production of a pod. These 
pods contained ovule-like bodies, and were very much larger than the ordinary seed- 
pods of the plant. 
About the beginning of June the clover-heads with enlarged pods had a very dif- 
‘ferent appearance; one of the white petals was to be seen protruding beyond the 
calyx, and partly enclosing the pod; this petal was always the vexillum; the re- 
maining parts of the flower being suppressed as before. 
As the season advanced, the production of the “horn-like pod”’ was less frequent ; 
and it was then principally that the substitution of leaves for flower-organs was to be 
observed: and at the present moment (Sept. 4) it would be difficult to find a single 
instance of change. 
From this it would seem, that, according as the conditions at any particular moment 
may be favourable to vigorous growth or otherwise, the plant advances to the pro- 
duction of floral organs or reverts to leaves; and as the formation of the several parts 
of the flower follow in succession, from the calyx upwards, so the part of the flower 
exhibiting the change will be higher according as the plani’s flowering-season has 
advanced. 
The changes indicated in the drawings accompanying the paper were as follows :— 
I. Calyx.—The calyx-teeth often rise into single leaves; but when compound leaves 
are formed, the division seems to be as follows: the two large equal teeth, which are 
_ Opposite the vexillum, form one ternate leaf, and another leaf is formed from the three 

WIL. Stamens.—Whatever changes the flower may exhibit, these organs are always 
| _in a state to be recognised, and their reversion to leaves less frequent than in any 
1a other part; so that there is more difficulty in determining the number of leaves 
| which go to form this portion. As two ternate leaves form the calyx and corolla, it 
might be supposed that the stamens were constructed out of the same number. The 
_ figures represent cases of a stamen reverting to a leaf with a true stamen attached 
to its stalk on either side; the single anterior stamen, when it reverts, seems always 
| _ disposed to form more than a simple leaf, and it is therefore probable that the ten 
__ stamens (9+-1) may be formed out of four sets of ternate leaves. 
4 _ IV. From the well-known character of the pod and pistil in Leguminose, it might 
_be expected that instances of reversion to leaf would be most frequent in this part of 
the flower; and a series might easily have been produced which would have repre- 
_ sented it in every stage of passage ; some of these were given. From these it would 
appear that the pod is not formed of a whole compound leaf, as either two scales, or 
two abortive leaves, are constantly to be seen at the base of the imperfect pod on 
: _ either side; the pod is therefore usually formed out of the middle leaflet. In one 
* * The paper was accompanied by a series of drawings on an enlarged scale. 
