. Contributions from the Hull Botanical Laboratory. Plants. 394 BOTANICAL GAZETTE [NOVEMBER sowing of the spores and the appearance above ground of the first tiny leaf of the sporeling. We have seen one sporeling with a fertile spike bearing a few sporangia while still attached to the pro thallium, but it is probable that ten or twelve years usually elapse between the germination of the spore and the development of a plant up to the spore-bearing stage. During the past twenty years we have made so many unsuccessful attempts to germinate Botrychium that we did not even try to test our theory by
. Contributions from the Hull Botanical Laboratory. Plants. 394 BOTANICAL GAZETTE [NOVEMBER sowing of the spores and the appearance above ground of the first tiny leaf of the sporeling. We have seen one sporeling with a fertile spike bearing a few sporangia while still attached to the pro thallium, but it is probable that ten or twelve years usually elapse between the germination of the spore and the development of a plant up to the spore-bearing stage. During the past twenty years we have made so many unsuccessful attempts to germinate Botrychium that we did not even try to test our theory by this method, but collected some circumstantial evidence which supports our conclusion that B. dissedum is a mutant from B. obliquum. Before presenting the evidence it is worth while to call attention to the distinguishing characters of the two forms. B. obliquum and its varieties have oblique leaflets with margins ranging from nearly entire to quite sharply serrate, sometimes doubly serrate, while B. dissedum has a leaflet, still oblique in topography, but so dissected that the specific name is very appropriate (figs. 3-5). This difference in leaves is recognizable even in the sporeling (figs. 6 and 7). The leaves of sporelings are simpler in out- line than those of larger plants, but the general character of the margins is char- acteristic from the first, so that there is no danger of confusing the forms. In B. obliquum and its varieties there is considerable variation in the shape of the leaflet and in the character of the margin; but, so far as the margin is concerned, the differences are confined to a greater or lesser degree of serration. The deepest serration of B. obliquum would not be mistaken for the deeply cut margins of B. dissedum. In B. dissedum there is also some variation in the margins, but the dissected character is always evident, the differ- ences being in the extent of the dissection (fig. 8). We are familiar, of course, with the great variations in the lea
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectplants, bookyear1895
