Term:
Septal unit spear-shaped
Septal unit spear-shaped
Definition:
A septal unit shape with septal unit head triangular and the base ob-triangular such that it appears spear-shaped as seen in a cross-section of the ovary. In this type of septal unit, all sides of the septal unit head are slanted in orientation but the basal sides are usually, but not always, shorter than the apical sides. Species that have equal sides, i.e. appearing like a diamond, are also classified as spear-shaped.
A septal unit shape with septal unit head triangular and the base ob-triangular such that it appears spear-shaped as seen in a cross-section of the ovary. In this type of septal unit, all sides of the septal unit head are slanted in orientation but the basal sides are usually, but not always, shorter than the apical sides. Species that have equal sides, i.e. appearing like a diamond, are also classified as spear-shaped.
Notes:
This type of septal unit differs from the arrowhead-shape because the base of the placenta is tapered back to the septum and is not truncate or extended somewhat from the base as it is in arrowhead-shaped septal units. For example, all species of Gustavia we have examined, except those belonging to Gustavia sect. Hexapetala (this section has arrowhead-shaped placentae), have this type of placenta.
This type of septal unit differs from the arrowhead-shape because the base of the placenta is tapered back to the septum and is not truncate or extended somewhat from the base as it is in arrowhead-shaped septal units. For example, all species of Gustavia we have examined, except those belonging to Gustavia sect. Hexapetala (this section has arrowhead-shaped placentae), have this type of placenta.