Distally lobed integuments in some Angiosperm ovules

In this treatise ‘De l’Ovule’ Warming (1878) remarked that although the borders of the integuments grow uniformly, very rarely a division into lobes can be observed. He mentioned Symplocarpus foetida (inner integument four-lobed), Lagarosiphon schweinfurthii (outer integument four- or five-lobed) and Juglans regia (two-lobed). Moreover he cited the report by some authors of an occasional occurrence of lobed integuments in a few more plants. More recently Leroy (1955) described bilobed single integuments in Juglans and Platycarya. Boesewinkel and Bouman (1967) demonstrated that these lobes arise as two separate primordia in Pterocarya and Juglans.