Revision of some Polypetalous Genera and Orders: Fremontia

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FREMONTIA [1], Torr. Sepala plana, omnino petaloidea, patentissima. Andrœcium regulare: columna æqualiter 5-fida: antheræ oblongo-lineares, utrinque emarginatæ, connectivo tenui haud producto adnatæ, loculis reniforme-incurvatis mox anfractuosis. Seem haud appendiculatum. Cotyledones marginibus leviter homotrope incurvis. — Contrary to the original description and figure, (which also represented an anomalous four-celled ovary, the like of which has not again been met with,) the stamens alternate with the sepals. So they in the Hand-tree flower, according to Adrien de Jussieu, who communicated a long and faithful description to the Flore des Serres (vii. 7-9) in 1851, probably his last botanical writing. Dr. Masters, in Gard. Chronicle, 1869, and in Seemann's Journal of Botany (vii. 298), with fresh flowers of Fremontia in hand, gives then position of the stamens correctly. When his insists, partly on this account, that the showy perianth of Fremontia is a corolla, he forgets that in Sterculiaceae and probably all the Malval cohort the stamens, whenever isomerous, stand before the petals or the place for them, i.e. alternate with the sepals: so that this evidence tells the other way. As for the caducous bractlets, which Dr. Masters takes for a reduced calyx, the five which he found is a most unusual number. We find only three, answering to the larger and less deciduous ones of the Hand-tree, and to the bractlets of most Sterculiaceæ.

Bentham, adopting a suggestion of Torrey, included these two genera [2] in this tribe or suborder Bombaceæ of Malvaceæ, describing the stamens as united in pairs with unilocular anthers, which was a forced hypothesis; also the calyx-segments as "leviter imbricatis." which was no slight diminution of the fact. But in the addenda et corrigenda to the first volume of the Genera Plantarum (two years earlier than Dr. Master's note), he changes this view, and transfers his subtribe Fremontieæ [3] to Sterculiaceæ as a new tribe.

It seems to me better frankly to recognise the peculiarities of these two genera, of which the leading one is the strongly quincuncial calyx, and not to force them into an order, not into a cohort, of which a valvate calyx is an essential and substantially an unvaried character. As a small order, it takes a comfortable position between the Guttiferal and Malval cohorts in the Genera Plantarum, connecting the two, and with no technical character alien to the former. [4]

[1] The alternate generic name of Fremontodendron is now the accepted form, but Fremontia continues in use as a vernacular name.
[2] Cheiranthodendron and Fremontodendron
[3] Consequent on the recognition of Fremontodendron as the correct generic name, the tribe becomes Fremontodendreae.
[4] More recent work has demonstrated conclusively that these genera belong to Malvaceae sensu APG, and to the Malvatheca clade therein. It has derived floral characters, with oppositifoliate, apetalous, flowers, with a quincuncial calyx, and the number of stamens reduced to 5, which makes classification on morphological grounds difficult.

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