The genus Eugenia (Myrtaceae) in southern Africa: Morphology and taxonomic value of pollen
1985; Elsevier BV; Volume: 51; Issue: 5 Linguagem: Inglês
10.1016/s0254-6299(16)31645-3
ISSN1727-9321
Autores Tópico(s)Botany, Ecology, and Taxonomy Studies
ResumoThe taxonomic significance of pollen morphology was assessed in 14 southern African species of Eugenia L Up to now African species of Eugenia were considered to be androdioecious and therefore pollen from both male and hermaphrodite plants was compared. All the investigated species produce pronounced dimorphic pollen. Pollen from male flowers is typically myrtaceous and resembles that of consistently hermaphroditic species of Eugenia in other parts of the world. Grains are free, radially symmetrical, isopolar, oblate to peroblate, (17)20-25(30) lim in equatorial diameter, triangular, goniotreme and tricolporate. Pollen from hermaphrodite flowers deviates considerably from the typical myrtaceous pattern. Grains are free, radially symmetrical, apolar or heteropolar, spheroidal, (22)28-35(40) μm in diameter and atreme or colpate. The lack of ora (endopores) suggests that these grains are most probably inviable (or almost so), thus rendering the flowers functionally female. All the investigated species therefore appear to be functionally dioecious. It was impossible to differentiate between species on the basis of palynological features. Neither did pollen morphology reflect a recently proposed subdivision of Eugenia in southern Africa. S. Afr. J. Bot. 1985, 51: 371–378 Die taksonomiese waarde van stuifmeelmorfologie is by 14 Suider-Afrikaanse Eugenia L.-spesies ondersoek. Tot nog toe is Eugenia in Afrika as androdiesies beskou en daarom is stuifmeel van beide manlike en tweeslagtige plante vergelyk. Uitgesproke dimorfiese stuifmeel word deur al die ondersoekte spesies geproduseer. Stuifmeel van manlike blomme is tipies Myrtaceae-agtig en stem met stuifmeel van die deurgaans tweeslagtige Eugenia-spesies in ander dele van die wereld ooreen. Korrels is vry, radiaalsimmetries, isopoler, oblaat tot peroblaat, (17)20-25(30) μm in ekwatoriale deursnee, driehoekig, goniotreem en trikolporaat. Stuifmeel van tweeslagtige blomme wyk opvallend van die tipiese Myrtaceae-patroon af. Korrels is vry, radiaalsimmetries, apoler of heteropoler, sferoTdaal, (22)28-35(40) μm in deursnee en atreem of kolpaat. Weens die afwesigheid van ora (endoporiee) word vermoed dat die korrels heel moontlik steriel (of so te se steriel) is. Dit impliseer dat die blomme funksioneel vroulik is. Dit wil gevolglik voorkom asof die ondersoekte spesies funksioneel tweehuisig is. Dit is onmoontlik om op grond van palinologiese kenmerke tussen die spesies te onderskei. Die onlangs voorgestelde onderverdeling van Eugenia in Suider-Afrika word ook nie deur die stuifmeelmorfologie weerspieel nie. S.-Afr. Tydskr. Plantk. 1985, 51: 371–378
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