. College botany; structure, physiology and economics of plants. Botany. 292 COLLEGE BOTANY and produce new gametophytes. Tke complete life history is illustrated in Fig. 141. The genus Biccia also belongs to the Marchantiales and con- tains a number of species, some of which are terrestrial and others aquatic. They are smaller than M. polymorpha and the antheridia and archegonia remain embedded in cavities of the thallus. They are the simplest of the Hepaticoe. The Jungermanniales contains a larger number of species than either of the other two groups. They grow under conditions ranging from
. College botany; structure, physiology and economics of plants. Botany. 292 COLLEGE BOTANY and produce new gametophytes. Tke complete life history is illustrated in Fig. 141. The genus Biccia also belongs to the Marchantiales and con- tains a number of species, some of which are terrestrial and others aquatic. They are smaller than M. polymorpha and the antheridia and archegonia remain embedded in cavities of the thallus. They are the simplest of the Hepaticoe. The Jungermanniales contains a larger number of species than either of the other two groups. They grow under conditions ranging from the extremely wet to the extremely dry. They are most abundant in the tropics and gTow most commonly on the ground, on tree trunks and on leaves. They are divided into two groups, the thal- lose forms, which resemble the Mar- chantiales, and the foUose forms, which resemble the mosses, but there is a gradual gradation between the two groups. However, the distinc- tive characters of the Jungermanni- Marchantia polymorpiia bearing two aleS IS tO be fouud in the archeTOnia archegoma] branches; (o) also a ^ single antheridial branch from a and the SPOrO'phyte. male plant. , ^ 7 The Anthocerotales is a small, temperate zone group, which is thought by many workers to represent the ancestral forms of the Pteridophytes. We cannot discuss this order in a limited work of this kind. It will be noted that in the Ilepatioa? the gametophyte is much larger than the sporophyte and that there are no true roots, stems or leaves. There is a differentiation of the cell structure but no collenchyma, sclerenchyma, fibrous, tracheary, sieve or laticiferous tissues. < The Musci or mosses are also a very old group of plants which are more highly differentiated than the Hepaticw. They ai-e widely distributed and were much more abundant during the carboniferous age of the earth's history than at the present 140.—(a) female plant. Please note that these images are extracted from scanned page i
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