14-2 MR. J. MIERS ON TWO GENERA OF PLANTS FROM CHILE. 



more internal leaflets bear the usual characters of petals. Were this distinction once 

 admitted, and we were to conclude the normal arrangement to be ternary, and to allow 

 the existence of an occasional binary combination, by the suppression of some of its parts, 

 all the difficulties of its variable structure could be easily explained. In the solitary 

 instance where the floral envelopes are only three (as in Konigia), we might look upon 

 it as an apetalous genus ; where they consist of six lobes, the three outer may be regarded 

 as sepals, and the others as petals ; or when nine, the six interior lobes as a double row 

 of petals. In like manner, when five in number, we may conceive the two outer lobes 

 (which in such cases are always more exterior) to be sepals, and the other three to be 

 petals; when four or eight, the same distinction may be made by dividing them into 

 binary series. This hypothesis, though only a modification of Mr. Bentham's, will obvi- 

 ously reduce the number of deviations from the normal rule. There does not indeed 

 appear any reason why the floral envelopes of the Polygonacece should not be entitled to 

 the same distinction into calyx and corolla, as is admitted, for instance, in the Polygalacece, 

 where the calyx is often comparatively large and petaloid in texture, or as in the Portu- 

 lacacece, where the same occurs, and where the number of sepals (different from that of 

 the petals) is only two, in the same manner as, according to my view, exist in Polygonum, 

 Fagopyrum, Coccoloba, Ceratogonwm, Fmex and Calligonwm, in which last-mentioned 

 genus the two exterior leaflets are larger and marcescent, showing the difference of their 

 nature from the three petals, which remain persistent about the fruit. The same decadence 

 of the sepals and persistence of the corolla occur also in the Portulacacece. In many other 

 genera of the Polygonacece with six floral segments, the outer series, which are different 

 in texture, fall away, while the petals remain, investing the achenium. This view of the 

 subject is much confirmed by the argument of Prof. Lindley*, where he offers very cogent 

 reasons for associating the Polygonacece with the Caryophyllacece and the Portulacacece, 

 with which orders they agree in the unsymmetrical inconstancy of their floral parts, in 

 their sepals being often of petaloid texture, in the insertion of their stamens upon a hypo- 

 gynous ring, quite free from the petals, in their somewhat stipitate ovarium, and in their 

 farinaceous albumen enclosing a curved embryo. The Caryophyllacece have also their 

 petioles somewhat vaginant. 



All the Eriogonece hitherto known accord with the normal rule, as they present six floral 

 segments in two series, nine stamens and three styles, but in the plant under considera- 

 tion, we have an unusual deviation from the general disposition, for here we find a quater- 

 nary arrangement, the involucre being generally 4-cleft, each flower having eight distinct, 

 very imbricated segments, eight stamens fixed upon the hypogynous support or gyno- 

 phorus, and four styles and stigmata. In accordance with the views above suggested, 

 I shall therefore consider the four outer segments as a calyx of four sepals, and the inner 

 lobes as a corolla of four petals. I will here remark, that in the same specimen I have 

 observed, though rarely, that some of the involucres contain flowers in which their parts 

 are trimerous, i. e. three sepals, three petals, six stamens, three styles and stigmata, but 

 the involucre in such case is still 4-pointed. 



* Vegetable Kingdom, p. 50. 





