| Full text | |
| Author(s): |
Graca Sajo, M.
[1]
;
Pabon-Mora, Natalia
[2]
;
Jardim, Jomar
[3]
;
Stevenson, Dennis W.
[2]
;
Rudall, Paula J.
[4]
Total Authors: 5
|
| Affiliation: | [1] IBUNESP, Dept Bot, BR-13506900 Rio Claro, SP - Brazil
[2] New York Bot Garden, Bronx, NY 10458 - USA
[3] Univ Fed Rio Grande do Norte, Dept Bot Zool & Ecol, BR-59078970 Natal, RN - Brazil
[4] Royal Bot Gardens, Richmond TW9 3AB, Surrey - England
Total Affiliations: 4
|
| Document type: | Journal article |
| Source: | AMERICAN JOURNAL OF BOTANY; v. 99, n. 4, p. 614-628, APR 2012. |
| Web of Science Citations: | 15 |
| Abstract | |
Premise of the study: The grass subfamily Anomochlooideae is phylogenetically significant as the sister group to all other grasses. Thus, comparison of their structure with that of other grasses could provide clues to the evolutionary origin of these characters. Methods: We describe the structure, embryology, and development of the flower and partial inflorescence of the monotypic Brazilian grass Anomochloa marantoidea. We compare these features with those of other early-divergent grasses such as Pharus and Streptochaeta and closely related Poales such as Ecdeiocolea. Key results: Anomochloa possesses several features that are characteristic of Poaceae, notably a scutellum, a solid style, reduced stamen number, and an ovary with a single ovule that develops into a single indehiscent fruit. Interpretation of floral patterning in Anomochloa is problematic because the ramification pattern of the florets places the bracts and axes in unusual positions relative to the primary inflorescence axis. Our study indicates that there is a single abaxial carpel in Anomochloa, probably due to a cryptic type of pseudomonomery in Anomochloa that resembles the pseudomonomery of other grasses. On the other hand, the Anomochloa flower differs from the ``typical{''} grass flower in lacking lodicules and possessing four stamens, in contrast with the tristaminate condition that characterizes many other grasses. Conclusions: Using the median part of the innermost bract as a locator, we tentatively homologize the inner bract of the Anomochloa partial inflorescence with the palea of other grasses. In this interpretation, the pattern of monosymmetry due to stamen suppression differs from that of Ecdeiocolea. (AU) | |