Seed morphology of genus Aconitum L. < 산림생물연구

- Aconitum L., commonly known as aconite, Monkshood, or wolf's bane, is a genus of family Ranunculaceae and comprising about 300 species. The perennial herbaceous plant is distributed mainly in the mountainous region of the Northern Hemisphere. Most of the species are extremely poisonous and must be handle carefully. Toxins extracted from the plant were historically used to kill wolves hence the name wolf's bane.
  
  The plant bear tubers or elongate, fascicled roots. Stem is either erect or twining. Leaves are simple or compound, basal and cauline, proximal leaves are petiolate and distal leaves are sessile or nearly so and cauline leaves are alternate. Leaf blades are palmately divided into 3-7 segments, rarely undivided. Inflorescence is terminal, sometimes also axillary, 1-32(-more) racemes or panicles. Flowers are bisexual and zygomorphic. Sepals 5(2 lower pendents, 2 lateral round-reniform, and 1 upper hood), petaloid, purple, blue, or yellow in color, not persistent in fruit. Petals 2, distinct, bearing near apex a capitate to coiled spur, concealed in hood, long-clawed; nectary present on spur. Stamens numerous, filaments with base expanded, anthers ellipsoid-globose. Pistils 3(-5) simple, ovules 10-20 per pistil and style present. Fruits follicles, aggregate, sessile, oblong, beak terminal, straight, 2-3 mm
  
  Seeds of the Aconitum are triangular and pyramidal in shape and usually with small, transverse, membranous lamella. A base, at the center of which the region of the hilum is found, and three faces can be distinguished. At the three edges are more or less well developed longitudinal wings, though in some cases these may be absent. Most of the Aconitum species exhibit warty ornamentation of the integument epidermal cells except on the top of longitudinal wings (when present) and on the hilum region. The seeds of Aconitum species can be described on following morphological parameters:
  
  Longitudinal wings are the epispermic expansion from the hilum zone to the apex of the triangle or pyramid. Based on the longitudinal wings, four types of seeds can be distinguished:
  - a) Presence of three longitudinal wings of comparable size (Fig. 3, 6, 7).
  - b) Presence of three longitudinal wings, one of which is distinctly more developed than the other two (fig not available).
  - c) Presence of only one longitudinal wing (Fig. 4, 9-11).
  - d) Longitudinal wings absent (Fig. 5, 8).
  The presence of only one or even without longitudinal wing in later three groups might be the result of disappearance of such wings from the group first. A seed morphological trend has been pointed out, characterized by the reduction of longitudinal wings on the edges with a concomitant development of the ridges on the seed faces expanding into transverse membranous wings. The seeds provided with three equally developed longitudinal wings along the edge and with faces devoid of ridges, may be regarded as the simplest type.
  
  These are the transverse expansion of the episperm on the lateral faces of the seed (Fig. 4, 5, 9-11). On the basis of development of transverse wings seed can be distinguished as:
  - a) Smooth faces without transverse expansion.
  - b) Faces with rough transverse expansion.
  - c) Faces with folded transverse expansion.
  - d) Faces with lamellate transverse expansion.
  The hilum is located on the more or less concave base of pyramid. According to the shape, hilum can be distinguished as:
  - a) A wide crateriform hilum: hilum has very long sloping walls practically joined to the base (Fig. 9).
  - b) A deep crateriform hilum: hilum has shorter, more slopping walls than a type 'a' and relatively larger base surface (Fig. 10).
  - c) A funnel shaped hilum: hilum possessing long, almost vertical walls that are clearly distinct from the base surface (Fig. 11).
  Episperm cells in Aconitum are usually elongated and they may be either rectangular or rectangular chiselled at the apex (Fig. 12, 13). On the basis of ornamentation they can be smooth or with warty ornamentation, spherical or round top papilla (Fig. 12-14).