292 OBSERVATIONS ON PLANTS
reference to the axis of the spike, in Polygaleae, namely, the fifth segment of the calyx being posterior or superior and the fifth petal anterior or inferior, is the usual relation in families the division of whose flower is quinary. This relation is in some cases inverted ; one example of which I have formerly pointed out in Lobeliacese/ as I proposed to limit it, and a similar inversion exists in Leguminosae. But this class also deviates from the more general arrange- ment of the parts of the flower with regard to each other. That arrangement consists, as I have long since remarked,^ in the regular alternation of the divisions of the proximate organs of the complete flower. To this arrangement, in- deed, many exceptions are well known ; and M. De Can- dolle has given a table of all the possible deviations, but without stating how^ many of these have actually been ob- served.^
In Leguminosse the deviation from the assumed regular arrangement consists in the single pistillum being placed opposite to the lower or anterior segment of the calyx.
In these two characters, namely, the relation of the calyx and corolla both to the simple pistillum and to the axis of the spike or to the bractea, Leguminosae diff'er from Rosacese in wdiicli the more usual arrangements are found.
But in those Rosaceae in which the pistillum is solitary and placed within the anterior petal, its relation to the axis of the spike is the same as that of Leguminosse, in wdiich it is within the anterior division of the calyx. And in all families, wdiether dicotyledonous or monocotyledonous, this, I believe, is uniformly the position of the simple solitary pistillum with regard to the spike or bractea.
The frequent reduction of Pistilla, in plants having the other parts of the flower complete in number, must have been generally remarked. But the order in wdiich these abstractions of pistilla take place, or the relations of the re- duced series to the other parts of the flower, have, as far as I know, never yet been particularly attended to. It will probably appear singular that the observation of these
=^ Prodr. Flor. Nov. lloll. ], ^j. 558. ^ -7^^^^^., ^/^^^^^ ^^, g^ ^^^ is3.
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