Evidence for apomixis in Amelanchier laevis (Rosaceae)

A description of apomoxis in Amelanchier leavis in Maine. 'Interspecific hybridization, polyploidy and poorly defined species boundaries characterize Amelanchier in northeastern North America. Similar phenomena are found in conjection with apomixis in other genera of the Pomoideae. Apomixis has been suspected in Amelanchier, but not demonstrated. Investigating the possibility of apomixis in natural populations of Amelanchier laevis in Maine, we have studied conventionally sectioned and stained ovules as well as unsectioned ovules cleared in Herr's 4.5 fluid using Nomarski differential interference contrast microscopy. The ovule is anatropous, bitegmic and crassinucellar, with one to several archesporial cells. In observations of numerous ovules, no tetrads of megaspores were observed. Polygonum-type megagametophytes develop from presumably mitotic divisions of archesporial cells.' /STUDY LOCATIONS:/ /MOUNT DESERT ISLAND/