4. Parachute, petasospores. The highly developed members of this group, _Taraxacum_, _Lactuca_, and other _Liguliflorae_ are connected through Senecio and _Eriophorum_ with the preceding. These represent the highest development of mobility attained by special modification. 5. Chaffy-pappose, carphospores. In this group are placed those achenes with a more or less scaly or chaffy pappus with slight mobility, as in _Rudbeckia_, _Brauneria_, _Helianthus_, etc. 6. Plumed, lophospores. In the fruits of this class, the style is the part usually modified into a long plumose organ, possessing a high degree of mobility, as in _Pulsatilla_, _Sieversia_, and _Clematis_. 7. Awned, ascospores. These are almost exclusively grasses, in which the awns serve for distribution by wind, water, or animals, and even, according to Kerner, by hygroscopic creeping movements. The mobility in many cases is great. 8. Spiny, centrospores. This group contains a few representatives which possess a moderate degree of mobility by attachment, as in _Tribulus_ and _Cenchrus_. 9. Hooked, oncospores. The members of this group are extremely numerous, and the degree of mobility as a rule is very high. All exhibit in common the development of hooks or barbs, by which they are disseminated in consequence of attachment, though the number, size, and disposition of the hooks vary exceedingly. 10. Viscid, gloeospores. In these, the inflorescence is more or less covered with a viscid substance, as in species of _Silene_, or the fruit is beset with glandular hairs, as in _Cerastium_, _Salvia_, etc. 11. Fleshy, sarcospores. These are intended for dissemination by deglutition, largely by birds; the effectiveness of the modification depends in a large degree upon the resistance of the seed envelope to digestion. The mobility varies greatly, but the area over which migration may be effected is large. 12. Nut-fruited, creatospores. This group includes those plants with nut fruits which are carried away and secreted by animals for food. 13. Flagellate, mastigospores. These are plants with ciliate or flagellate propagative cells, i. e., zoogonidia, as in _Protococcus_, _Ulothrix_, _Oedogonium_, _Ectocarpus_, etc., or with plant bodies similarly motile, _Bacteriaceae_ and _Volvocaceae_.