Descriptor : specialisation value

Descriptor type : categorical

definition by: V. Cheadle. The origin and certain trends of specialization of the vessel in the Monocotyledoneae. Amer. J. Bot., 30:11–17, 1943.

application in palms by: L. H. Klotz. Form of the perforation plates in the wide vessels of metaxylem in palm. J. Arnold Arbor., 59(2):105–128, 1978.

0 — tracheids only — definite vessels not observed
1 — multiple perforation plates with "pithlike" perforations that span ≤ 1 vessel-parenchyma pit on the adjacent lateral wall
2 — multiple perforation plates with "narrow" perforations that span >1 to ≤ 2 vessel-parenchyma pits
3 — multiple perforation plates with "medium size" perforations that span >2 to ≤ 5 vessel-parenchyma pits
4 — multiple perforation plates with "wide" perforations that span >5 vessel-parenchyma pits, or with ≤ 3 bars
5 — mixture of multiples perforation plates (as in #4) and simple perforation plates
6 — simple perforation plate only

[0] tracheids only — definite vessels not observed

tracheids only — definite vessels not observed

[1] multiple perforation plates with "pithlike" perforations that span ≤ 1 vessel-parenchyma pit on the adjacent lateral wall

1 — multiple perforation plates with "pithlike" perforations that span ≤ 1 vessel-parenchyma pit on the adjacent lateral wall

[2] multiple perforation plates with "narrow" perforations that span >1 to ≤ 2 vessel-parenchyma pits

2 — multiple perforation plates with "narrow" perforations that span >1 to ≤ 2 vessel-parenchyma pits

[3] multiple perforation plates with "medium size" perforations that span >2 to ≤ 5 vessel-parenchyma pits

3 — multiple perforation plates with "medium size" perforations that span >2 to ≤ 5 vessel-parenchyma pits

[4] multiple perforation plates with "wide" perforations that span >5 vessel-parenchyma pits, or with ≤ 3 bars

4 — multiple perforation plates with "wide" perforations that span >5 vessel-parenchyma pits, or with ≤ 3 bars

[5] mixture of multiples perforation plates (as in #4) and simple perforation plates

5 — mixture of multiples perforation plates (as in #4) and simple perforation plates

[6] simple perforation plate only

6 — simple perforation plate only

Hierarchy

wide metaxylem element
 |
 |_ specialisation value

Belongs to the groups