Characteristics of the phloem and the cortex

Both species have sieve-tube groups, often arranged in short radial rows (Figs. 66 and 67). Ray dilatations are distinct (Figs. 66 and 67). Phellem is absent (Fig. 66).

secondary ray

Fig. 60. Semi-ring-porous xylem with radial multiples. Ray cells at ring boundaries are unlignified. Axial parenchyma is para-tracheal. Stem basis of a 40 cm-high cham-aephyte, limestone rock, mountain zone, Piemont, Italy. Helleborus foetidus, transverse section.

Left Fig. 57. Semi-ring-porous xylem with distinct rings and very large rays. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, France. Helleborus viridis, transverse section.

Right Fig. 58. Semi-ring-porous xylem with distinct rings. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, Piemont, Italy. Helleborus foeti-dus, transverse section.

Right Fig. 58. Semi-ring-porous xylem with distinct rings. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, Piemont, Italy. Helleborus foeti-dus, transverse section.

Fig. 61. Vessels with simple perforations and round inter-vessel pits. Fibers contain nuclei. Stem basis of a 40 cm-high cham-aephyte, limestone rock, mountain zone, Piemont, Italy. Helleborus foetidus, radial

Fig. 59. Semi-ring-porous xylem with radial multiples. Axial parenchyma is paratracheal. See Fig. 57. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, France. Helleborus viridis, transverse section.

Fig. 60. Semi-ring-porous xylem with radial multiples. Ray cells at ring boundaries are unlignified. Axial parenchyma is para-tracheal. Stem basis of a 40 cm-high cham-aephyte, limestone rock, mountain zone, Piemont, Italy. Helleborus foetidus, transverse section.

Fig. 61. Vessels with simple perforations and round inter-vessel pits. Fibers contain nuclei. Stem basis of a 40 cm-high cham-aephyte, limestone rock, mountain zone, Piemont, Italy. Helleborus foetidus, radial simple pits simple pits

Left Fig. 62. Vessels with very fine helical thickenings. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, Piemont, Italy. Helleborus foetidus, radial section.

Right Fig. 63. Fibers with small and tra-cheids with large pits in the latewood. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, France. Helle-borus viridis, radial section.

Left Fig. 64. Confluent large ray. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, France. Helleborus viridis, tangential section.

Right Fig. 65. Upright ray cells. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, France. Helleborus viridis, radial section.

Left Fig. 66. Phloem with small groups of sieve tubes and ray dilatations. A phel-lem is absent. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, France. Helleborus viridis, transverse section.

Right Fig. 67. Phloem with small groups of sieve tubes and ray dilatations. A phel-lem is absent. Stem basis of a 40 cm-high chamaephyte, limestone rock, mountain zone, Piemont, Italy. Helleborus foetidus, transverse section.

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