Morphological Studies on a New Species of Marchantia

Abstract

1. This study deals with an unnamed species of Marchantia growing in the Peruvian Andes. Male and female receptacles were studied and the development of the sporophyte and sex organs was traced. 2. The first division in the zygote is transverse or obliquely transverse, dividing the embryo into a distal portion which will become the capsule and a proximal region which will become foot and seta. 3. The second division is perpendicular to the first. 4. Periclinal and anticlinal divisions form a spherical mass of cells. The distal region takes a deeper strain and later forms sporogenous cells. 5. A peripheral layer of cells around the sporogenous cells forms the capsule wall; the walls of these cells later show bandlike thickenings. 6. A cap of sterile cells is present in the apical region from the time the cells of the sporogenous region first elongate until the sporophyte is mature. These cells also have thickenings. 7. At one stage the elongated sporogenous cells are binucleate, but by divisions soon result in uninucleate cells, and these give rise to rows of spore mother cells. 8. The stalk remains short until the spores are mature, and then the cells elongate and push the capsule out through the calyptra. 9. The antheridium has a typical development and also has paraphyses and a noticeably long and massive stalk. 10. The archegonium development is typical of M. polymorpha. 11. Two androgynous receptacles with both kinds of sex organs in their ordinary positions were found.