The origin and distribution of inter- and intraxylary phloem inLeptadenia

摘要: 1. In Leptadenia spartium and L. reticulata there are three phloem regions: (a) the outer normal phloem, (b) intraxylary or inner (c) interxylary which forms inclusions in wood. 2. The patches of arise from pith cells, but later stages even xylem parenchyma cells adjacent to take part their formation. In old stems a cambium is differentiated on faces these groups produces some secondary centripetally. 3. The present stem, becomes thin-walled produced centripetally by cambium. Later resumes its activity with result that become embedded xylem. 4. Owing an enlargement island fact it surrounded all sides woody xylem, often compression crushing tissues centre. 5. A weak has occasionally been observed differentiate one more than side older islands. 6. A comparison Strychnos nux-vomica shows latter islands always centrifugally due formation complementary cambial segment side, whereas same both as well side.