. Dansk botanisk arkiv. Plants; Plants -- Denmark. F. Børgesen: List of species. 449 The chromatophore is a parietal plate with a large lateral pyrenoid, protruding far into the lumen of the cell. The sporangia occur at the base of the branches; in the spe- cimens found one, two, or, more rarely, three upon each branch, The sporangia are pedicellate or more rarely the uppermost sessile. The sporangia are oval in shape; they have a thick wall especially at their upper end. They are about 21 fi long and 13 // broad. From this plant Acr. flexuosum Vickers chiefly differs in its thinner filaments
. Dansk botanisk arkiv. Plants; Plants -- Denmark. F. Børgesen: List of species. 449 The chromatophore is a parietal plate with a large lateral pyrenoid, protruding far into the lumen of the cell. The sporangia occur at the base of the branches; in the spe- cimens found one, two, or, more rarely, three upon each branch, The sporangia are pedicellate or more rarely the uppermost sessile. The sporangia are oval in shape; they have a thick wall especially at their upper end. They are about 21 fi long and 13 // broad. From this plant Acr. flexuosum Vickers chiefly differs in its thinner filaments and by the presence of ramuli, upon which the sporangia are placed. Our plant ought also to be compared with Acr. Dmiesii (Dillw.) Nagl. showing in its short, thick-walled cells and whole ramification great hkeness to this species. But it differs in an essential way especially by the lack of the repeatedly ramified branchlets. The plant was gathered in shallow water at the end of Fe- bruary. St. Croix: Salt River. 17. Acrochætium unipes Borgs. 18. — opetigenum Borgs. 19. Acrochætium robustum Borgs. When I described this plant I had not come across young specimens. In fig. 418 the basal parts of two young plants are figured; in these the basal discs are not yet developed. From these figures it seems quite clear, that the germinat- ing spore during its growth produces downwards the process which pene- trates into the tissue of the host. The process has an acute base and thick walls. It is not separated from the original germinating spore by any wall. The process is the only endophytic part of the plant; the ori- ginal spore and the small disc gradual- Fig. 418. Acrochætium robustum 1 , , , , ., • 1 i- Borgs. Bases of two young plants, ly developed round it are epiphytic. (About 250:1). Dansk Botanisk Arkiv, Bd. 3. Nf. 1 (1920). 29. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and ap
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