=265. Position of disseminule.= The position on the plant of the organ to be disseminated, i. e., its exposure to the distributing agent, plays a considerable part in determining the degree of mobility. In the majority of plants, the position of the inflorescence itself results in maximum exposure, but in a large number of forms special modifications have been developed for placing the spores or seeds in a more favorable position. In both cases, there are often present also devices for bringing about the abscission of the seed or fruit. It is, moreover, self-evident that the height of the inflorescence above ground or above the surrounding vegetation is likewise of considerable importance in increasing the trajectory. It is yet too early to make a complete classification of contrivances for placing disseminules in the most favorable exposure, but the following will serve as a basis for future arrangements. 1. In all operculate _Discomycetes_, and especially in the _Ascobolaceae_, where the asci project above the hymenium, the spores are raised above the surface by tensions within the apothecium. This might be regarded as dissemination by expulsion, if it were not for the fact that the spores fall back into the cup, unless carried away by the wind. 2. In _Gasteromycetes_ and in certain _Hepaticae_, the spores are not only elevated slightly above the sporophore by the expanding capillitium or by the mass of elaters, but they are also held apart in such a way that the wind blows them out much more readily. 3. In _Bryophyta_, the sporophore regularly dehisces by a slit, or is provided with a peristome. Both structures are for the purpose of sifting the spores out into the wind; by reason of their hygroscopicity, they also insure that the spores will not be shaken out in wet weather. 4. In a few grasses, such as _Stipa_ and _Aristida_, the twisting and intertwining of the awns lift the floret out of the glumes, and at the same time constitute a contrivance readily blown away by the wind or carried by attachment. 5. In certain _Compositae_, the involucral scales are reflexed at maturity, and at the same time the disk becomes more or less convex, serving to loosen the achenes. This result is also secured in certain species by the drying and spreading of the pappus hairs. 6. The scapose _Liguliflorae_, _Taraxacum_, _Agoseris_, etc., are characterized by the elongation of the scape after anthesis, with the result that the head is raised to a considerable height by the time the achenes are mature. 7. Carpotropic movements, though primarily for another purpose, often serve to bring seeds and fruits into a better position for dissemination.