1 | Rays partly very wide (over 10 cells) and very high; stems without included phloem. |
1' | Rays narrow, inconspicuous; stems generally with included phloem, either as isolated islands or as concentric bands, in some species without included phloem. |
2 | Woody cylinder stron ly indented by the thick bark (cross section); wide rays hardly contrastmg in colour with the ground tissue. |
2' | Woody cylinder not indented by the thin or moderately thick bark of even width; rays conspicuous by contrasting colour. |
3 | Wide rays without unlignified cells. |
3' | Wide rays with 1-4 rows of unlignified cells at the margin of the growth rings. |
4 | Silica bodies abundant in ray cells; stems with a red exsudate. |
4' | Silica absent, crystals often abundant in ray cells; stems without red exsudate. |
5 | Vessels moderately numerous, from 15-40(100) per sq. mm, radial multiples always present. |
5' | Vessels rather few, less than 15 per sq. mm, radial multiples rare. |
6 | Septate fibres conspicuous, numerous, in one cell wide concentric bands. |
6' | Septate fibres present but generally scattered among the fibre-tracheids, often rare and difficult to observe. |
7 | Crystals numerous, mainly in the unlignified ray cells and in sheathing ray cells. |
7' | Crystals not very numerous, in random distribution. |
8 | Included phloem absent. |
8' | Included phloem present. |
9 | Included phloem present as scattered strands; usually low trees. |
9' | Included phloem in different arrangement; lianas or shrubs. |
10 | Strands of included phloem arranged in concentric rings; lianas. |
10' | Included phloem in narrow concentric bands, with or without radial or oblique connective tissue. |
11 | Included phloem in concentric bands, without interconnections. |
11' | Included phloem rings interconnected radially or obliquely. |