Ovule Development Inornithogalum Caudatum(liliaceae) With a Review of Selected Papers on Angiosperm Reproduction

SUMMARY Ornithogalumovules are bitegmic: the inner is initiated first, but both attain maturity at the same time. Both integuments are derived from the epidermal layer of the nucellus and are covered by a cuticle. Inner integument cells define the micropyle and those which line it are secretory. An outer integument is present only on the distal (non‐funicular) side of the ovule. Its proximal portion apparently is fused congenitally with the funiculus. A funiculus attaches the ovule (and seed) to placental tissue. Proliferation of cells at the base of the funiculus contributes to development of the obturator. Funicular curvature causes the ovules to assume an anatropous orientation. A procambial strand branches from a ventral vein of the carpels and differentiates acropetally in the funiculus. At ovule maturity, vascular tissue terminates in the chalaza a few cells removed from the hypostase. Terminal cells of the vascular bundle consist only of tracheary elements with annular thickenings.