THE ANDROECIUM IN PLAGIOCHASMA APPENDICULATUM L. ET L. AND P. ARTICULATUM KASHYAP

S. R. Kashyap
1919 New Phytologist  
WITH TWO FIGUUHS IN THE TEXT.] 'T^HE genus Plagiochasma was worked out, both as regards its -•-structure and development, by Leitgeb who gave a derailed account of it in his classical treatise, " Untersuchungen iiber die Lehermoose," Vol. VI, 1881. Plagiochasma appendiculaium ¥/as one of the five species which be examined. He gave a fairly fulll account of the structure of the thallus and tbe female leceptacfe in the genus but only a single paragraph is devoted to the male receptacle,
more » ... h be gives many figures of the female receptacle at various stages of development, the male receptacle is siot figured even once. More recently, Evans, in the Bulletin of the Torreya Botanical Club (Vol. XLil, 1915), has given a comprehensive account of the genus with very full descriptions of the American species. He refers to Leitgeb's and the present writer's work, and says : " The androecia vary in outline from circular to more or less crescentic or cordate, with the convex side turned towards the base of the thalius. These crescentic androecia, as Leitgeb notes, should not be confused with the dichotomous androecia occasionally found in Lunularia, wbere two growing points are involved. They represent, according to his ideas, a persistence of the two-lobed condition at tbe apex of the ordinary thallus, where the single growing point lies in the indentation hetween the lobes. Kashyap, however, aays that in both P. ippendiculatum and P. articulatum the androecium has usually two growing points, and implies that the horse-shoe shape is therefore due to a forking. Unfortunately, he adduces no conclusive evidence to support his position." According to tlie present writer's experience it is so easy to satisfy oneself regarding the two growing points in the androecium in spirit material that the failure of two such accurate observers as Leitgeb and Evans to notice them can only be due to unsatisfactory herbarium material. As the importance of this point lies even far beyond the genus Plagiochasma' itself, it was decided to clear it up by examining a large number of spirit specimens collected by tbe writer in various parts of the western Himalayas, chiefly Mussoorie.
doi:10.1111/j.1469-8137.1919.tb07301.x fatcat:qknjfe2lfve4jducdyzw7jzfta