=329. Sporocarp.=—After the egg is fertilized the cells of the threads near the egg grow up around it and form a firm covering one cell in thickness. This envelope becomes brown and hard, and serves to protect the egg. This is the “fruit” of the coleochæte, and is sometimes called a sporocarp (spore-fruit). The development of the cell mass and the zoospores from the egg has been described above. Some of the species of coleochæte consist of branched threads, while others form circular cushions several layers in thickness. These forms together with the form of our plant C. scutata make an interesting series of transitional forms from filamentous structures to an expanded plant body formed of a mass of cells. =330. COMPARATIVE TABLE FOR SPIROGYRA, VAUCHERIA, ŒDOGONIUM, COLEOCHÆTE.= -----------+-------------------------------------------------------- | GAMETOPHYTE. (Bears the sexual organs and gonidia.) -----------+-----------+---------+------------+--------------------- |Vegetative | Growth. |Multipli- | Sexual Reproduction. | Phase. | | cation.+--------------------- | | | | Sexual Organs. -----------+-----------+---------+------------+--------------------- Spirogyra. |Simple |All |By breaking | Undifferentiated. |threads of |cells |up of | Any cell of thread. |cylindrical|divide |threads. | Conjugate by tube. |cells. |and | | | |grow. | | -----------+-----------+---------+------------+--------------------- |Branched |Limited |By | Differentiated. |threads, |to ends |multiciliate|Antheridia|Oogonium, Vaucheria. |continuous.|of |zoogonidia, |slender |large | |threads |and other |cells on |on special | |and |cells, from |special |rounded | |branches.|terminal |branches. |cell, | | |portions. | |branch, | | | | opens | | | | |and emits | | | | |bit of | | | | |protoplasm. -----------+-----------+---------+------------+----------+---------- |Simple |Limited |By oval | Differentiated. |threads of |to |zoogonidia, |Antheridia|Oogonium, Œdogonium. |cylindrical|certain |with crown |disk- |changed |cells. |portions |of cilia. | shaped, |vegetative | | of |Any cell |several |cell, opens | |thread. |may form a |from one |and emits | | |single |vegetative|bit of