Thursday, February 8, 2018

[Botany • 2017] Alphonsea glandulosa • A New Species (Annonaceae) from Yunnan, China

Alphonsea glandulosa  Y.H. Tan & B. Xue

in Xue, Shao, Saunders & Tan, 2017. 


Alphonsea glandulosa sp. nov. is described from Yunnan Province in south-west China. It is easily distinguished from all previously described Alphonsea species by the possession of glandular tissue at the base of the adaxial surface of the inner petals. Nectar was observed throughout the flowering period, including the pistillate phase and subsequent staminate phase. Small curculionid beetles were observed as floral visitors and are inferred to be effective pollinators since they carry pollen grains. A phylogenetic analysis was conducted to confirm the placement of this new species within Alphonsea and the evolution of the inner petal glands and specialized pollinator reward tissues throughout the family.

Fig 2. Flower and fruit morphology of Alphonsea glandulosa.
A, Branch, showing leaf-opposed inflorescence position, and lanceolate leaves. B, Abaxial view of the inflorescence, showing 5–6 carpels per flower. C, Adaxial view of the inflorescence, showing pubescent pedicels with one densely pubescent medial bract (arrowed). D, Fruit with subglobose monocarps. E, Single monocarp, dissected to show seed arrangement.
—Photos: Yun-hong Tan.

Alphonsea glandulosa is unusual in the genus, however, in having multiple flowers (often 5 to 9) in each inflorescence. Although most Alphonsea species have inflorescences with only 1–4 flowers, there are two species, A. philastreana (Pierre) Finet & Gagnep. and A. ventricosa (Roxb.) Hook. f. & Thomson, which have more than four flowers per inflorescence.

Alphonsea glandulosa Y.H. Tan & B. Xue, sp. nov.

Diagnosis: Alphonsea glandulosa is unique amongst Alphonsea species in having a nectar gland at the base of the adaxial surface of each inner petal. It is most similar to A. philastreana (Pierre) Finet & Gagnep., but differs in having a greater number of secondary veins on each side of the leaf, greyish to yellowish pubescent flower buds, longer pedicels, a greater number of carpels per flower, a smaller number of ovules per carpel, and globose to shallowly bilobed stigmas.

Etymology: The specific epithet reflects the presence of nectar glands at the base of the adaxial surface of each inner petal.

Bine Xue, Yun-Yun Shao, Richard M. K. Saunders and Yun-Hong Tan. 2017. Alphonsea glandulosa (Annonaceae), A New Species from Yunnan, China. PLoS ONE. 12(2); e0170107. DOI: 10.1371/journal.pone.0170107

A New Species of Alphonsea Found in Xishuangbanna

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