Peloria, then, is especially interesting physiologically as well as morphologically; it is also of value in a systematic point of view, as showing how closely the deviations from the ordinary form of one plant represent the ordinary condition of another; thus, the peloric Calceolarias resemble the flowers of Fabiana, and De Candolle,[242] comparing the peloric flowers of Scrophulariaceæ with those of Solanaceæ, concluded that the former natural order was only an habitual alteration from the type of the latter. Peloric flowers of Papilionaceæ in this way are indistinguishable from those of Rosaceæ. In like manner we may trace an analogy between the normal one-spurred Delphinium and the five-spurred columbine (Aquilegia), an analogy strengthened by such a case as that of the five-spurred flower of Delphinium elatum described by Godron.[243] The Corydalis, before referred to, is another illustration of the same fact, the structure being the same as in Dielytra, &c.

The ordinary irregular flowers may possibly be degenerated descendants of a more completely organized ancestor, and some of the cases of peloria may therefore be instances of reversion; some ancient Linaria may, perhaps, have had all its petals spur-shaped, and the cases of irregular peloria now found may be reversions to that original form. When both regular and irregular forms of peloria occur on the same plant, as they frequently do in Linaria, the one may be perhaps considered as a reversion to a very early condition, the other to a later state, when all the petals were irregularly formed. But before we can assert the truth of this surmise we must have better evidence as to what the original condition really was than we have at present.

The proximate cause of irregular peloria has been considered to be excess of nourishment, but evidence as to this point is very conflicting. Willdenow states that "radices peloriæ, solo sterili plantatæ, degenerant in Linariam," ('Sp. Plant.,' iii, p. 254); but this opinion is counterbalanced by that of others, while the frequent existence of both forms on the same plant, at the same time, seems to negative the supposition of any direct effect from external circumstances.

The following are the plants in which irregular peloria has been most often observed:

The literature of peloria is very extensive. The following are the principal papers, not already mentioned, which relate to the subject, arranged under the genera, placing those first which are most subject to this anomaly (see also Regular Peloria).

Linaria.—Adanson, 'Fam. Plant.,' t. i, p. 110. Jussien, 'Gen. Plant.,' p. 120. Poiret, 'Encycl. Method, Suppl.,' t. iii, Jaeger, 'Missbilld. der Gewachs.,' pp. 94, 97, and 313. Cassini, 'Op. Phytol.,' t. ii, p. 331. Ratzebourg, 'Animadv. ad pelor. spectand.,' 1825. Turpin. 'Ic. Veget.,' tab. xx, f. 16. Curtis, 'Flor. Londin.,' i, 118. Hopkirk, 'Flora Anom.,' pl. vii, figs. 1, 2, 3. Haller, 'Act. Helvet.,' 2, p. 25, t. iv. De Candolle, 'Flore Franc.,' t. iii, p. 583. Sowerby, 'Engl. Bot.,' iv, 260, ed. Syme, tab. 963. Chavannes, 'Mon. Antirrhin.' Delavaud, 'Bull. Soc. Bot. France,' 1858, p. 689; id., 1860, p. 175. Heufler, 'Linnæa,' xvii, tab. ii. Weber, 'Verhandl. des Nat. Hist. Vereins. f. d. Rh. Preuss.,' 1850, tab. i, figs. 1–8. 'Verh. Nat. Hist. Ver. Rh. Preus.,' 1849, vol. vi, p. 290, tab. xiii.—Antirrhinum, Clos, 'Mém. Acad. Toulous.,' vi, 1862. Chavannes, 'Mon. Antirrh.,' p. 62. Fresenius, 'Mus. Senkenb.,' ii, t. iv, fig. 10. 'Bot. Soc. Edinb.,' 1851, July 10.—Calceolaria, Chamisso, 'Linnæa,' t. vii, p. 206. Guillemin, 'Archiv. Bot.,' t. ii, p. 1 et 136. Schlechtendal, 'Linnæa,' xii, p. 686. Ernst Meyer, 'Linnæa,' xvi, 26, tab. iii. Morren, 'Bull. Acad. Belg.,' t. xv, n. 7, et t. xviii, p. 583. 'Gard. Chron.,' 1850, p. 389; ibid., 1866, p. 612.—Viola, Leers, 'Flor. Herborn.,' p. 145. De Candolle, 'Organ. Veget.,' t. i, p. 519, pl. xlv. Forbes, 'Proc. Linn. Soc.,' June 6, 1848, p. 382. Hildebrand, 'Bot. Zeit.,' 1862, vol. xx, tab. viii.—Orchidaceæ, His, 'Jourl. Phys.,' 65, p. 241. Wydler, 'Arch. Bot.,' t. ii, p. 310, tab. xvi. R. Brown, 'Obs. organ. Orchid.,' p. 698. A. Richard, 'Mém. soc. d'hist. nat.,' t. i, p. 212. Greville, 'Flora Edinens.,' p. 87 (Corallorhiza). Curtis, 'Flora Londinensis,' t. lxxxii. Morren, C., 'Bull. Acad. Roy. Belg.,' t. xix, part ii, p. 171. Clos, 'Mém. Acad. Sc. Toulous.,' 5 ser., vol. iii. Caspary, 'Schrift. K. Gesellsch. Königsberg,' 1860, i, 59. Masters, 'Jourl. Linn. Soc.,' vol. viii, p. 208 (Ophrys, Pogonia). Duchartre, 'Bull. Soc. Bot. Fr.,' vol. vii, 1860, p. 26, Cattleya. Cramer, 'Bildungsabweich.'—Limosella, Baillon, 'Adansonia,' i, p. 305. (Flower normally irregular, becoming regular "à force d'irregularité.")—Chelone, Chamisso, 'Linnæa,' vii, p. 206,—Clitoria, Bonavia, 'Gard. Chron.,' 1868, p. 1013. In this latter communication, published as this sheet is passing through the press, the author gives an interesting account of the transitional stages between the ordinary papilionaceous condition and the regular form which is like that of a Rosaceous plant. The peloric form is stated to be transmitted by seed.

For other references see Moq.-Tandon, 'El. Terat. Veget.,' p. 186. Hallier, 'Phytopathol.,' p. 151.

FOOTNOTES:

[232] 'Amœn. Acad.,' i, p. 55, t. iii (1744):—The following note refers to Linné's notion that these forms were due to hybridization. It is extracted from Gmelin's edition of the 'Systema Naturæ,' 1791, p. 931. "Linariæ proles hybrida, ejusdemque qualitatis et constans, radicibus infinite sese multiplicans charactere fructificationis diversissima, corolla regulari, quinque-corniculata, pentandra, ut genus proprium absolute constitueret et distinctissimum, nisi fructus frequentissime abortiret. Naturæ prodigium. Ita quidem a Linné. Verisimilor autem videtur ea opinio, quæ peloriam pro peculiari degeneratione monstrosa floris habet, in quam inclinare hoc genus (Linaria) præ aliis, similis a forma deflexio in aliis speciebus, e.g. spurio Elatine, cymbalaria, observata, ... Merk., 'Goett. gel. Anz.,' 1774, n. 121. Linck, 'Annal. Naturg.,' i, p. 32."