from Wiktionary, Creative Commons Attribution/Share-Alike License
- proper n. A taxonomic order within the class Marchantiopsida — the chambered liverworts.
from the GNU version of the Collaborative International Dictionary of English
- proper n. An oder of liverworts with gametophyte differentiated internally.
from The Century Dictionary and Cyclopedia
- An order of cryptogamic plants of the class Hepaticæ, characterized by athalloid, dorsiventral proembryonal generation, the antheridia and archegonia borne in groups on the surface of the thallus or on stalked receptacles, the sporogonia consisting of a spherical capsule with or without a short stalk.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. liverworts with gametophyte differentiated internally
The Marchantiales are a series of thalloid forms, in which the structure of the thallus is specialized to enable them to live in more exposed situations.
In the Marchantiales the chief supply is obtained from the soil by the rhizoids, and its loss in transpiration is regulated and controlled.
In most species of _Riccia_ the air-chambers are only narrow passages, but in the other Marchantiales they are more extended.
Marchantiales, can be recognized, but more often a prolonged dry season is survived in some resting state.
The Marchantiales form an obviously natural evolutionary group, and the same is probably true of the Jungermanniales, although in neither case can the partial lines of progression within the main groups be said to be quite clear.
The lower members of the Jungermanniales are also thalloid, but the thallus never has the complicated structure characteristic of the Marchantiales, and progress is in the direction of the differentiation of the plant into stem and leaf.
Such a form as _Sphaerocarpus_, which has features in common with the lower Marchantiales, enables us to form an idea of the divergence of the two groups from a common ancestry.
P. 703, Marchantiales: "Marchantia polymorpha and Lunularia": 'Marchantia, polymorpha' in original p. 707, Fig. 14: "Andreaea petrophila": 'pelrophila' in original
The Marchantiales are divided into a number of groups which represent distinct lines of advance from forms like the