Ovular development and morphology in some magnoliaceae species

Floral phenology and ovular development ofLiriodendron tulipifera are described. The ovule primordia are initiated in December, followed by prominent development in March, and the ovules are mature in May. The inner integument is formed as an annular rim on the incurving ovule primordia, but the outer integument develops as a semi-annular rim interrupted on the concave side of the funicle. Later, an outgrowth, which is interpreted here as an obturator, arises on the concave side of the funicle. The funicular outgrowth arises far from the inner integument, while the outer integument is close to the inner. The outer integument and the funicular outgrowth together form an envelope complex. Later the outer integument produces two distal lobes, which disappear at maturity. Mature ovules of the threeMagnolia species examined have similar lobes. It is suggested that the hood-shaped outer integument is primitive in angiosperms.