Tribe III. APHYLLjE, or LEAFLESS FLOWERLESS 



PLANTS. 



Acotyledones, Agardh Aph. 72. (1821). — Homonemea, Fries. Syst. Orb. P<?g\ 33. (1825). — ■ 

 .Acotyledones, Class 1. Ad. Brongn. in Diet. Class (1824). — Cryptogamice, 3d Circle, 

 T. F. L. Nees v. Escnbeck und Ebermaier Handb. der Med. Bot. 1. 18. (1830.) 



Diagnosis. Flowerless, leafless plants, destitute of vascular tissue, with 

 no distinct axis of growth, the sporules simple and lying naked in the substance 

 of the plant. 



In this tribe we have arrived at the limits which separate the vegetable from 

 the animal kingdom. We have not only passed beyond the dominion of the 

 stamens and pistils, but we have no longer any trace, however ambiguous, of 

 more than one form of reproductive matter. It is even uncertain whether this 

 matter will reproduce its like, and whether it is not a mere representation of 

 the vital principle of vegetation capable of being called into action either as a 

 Fungus, an Alga, or a Lichen, according to the particular conditions of heat, 

 light, moisture, and medium, in which it is placed ; producing Fungi upon 

 dead or putrid organic beings ; Lichens upon living vegetables, earth, or 

 stones ; and Alga? where water is the medium in which it is developed. The 

 nearest approach to animals is in the tribes of Algae called Anthrodieae and 

 Chaoduieaa, where it is perhaps impossible to decide whether some of the spe- 

 cies are not actually animalcules. 



It is not easy to settle the limits of the orders of this part of vegetation. 

 Linnaeus and Jussieu had but two divisions, viz., Alga?, including Lichens and 

 Fungi ; and they have been followed by some modern botanists, particularly 

 Fries and Wahlenberg. Others have been satisfied with separating the Lichens 

 from Algae, which, indeed, was virtually done by most of those who acknow^ 

 ledged but two divisions, and with admitting three equally distinct groups. 

 Borne, on the contrary, have sought to multiply them, as Decandolle and others, 

 by introducing a tribe called Hypoxyla ; Dr. Greville by adopting the latter, 

 Gastromyci, Byssoideae, and Epiphytae, and proposing a new group under the 

 name of Chaetophoroideae ; and finally, M. Adolphe Brongniart, who carries 

 the number of groups in this division of Acotyledones as far as 12, viz. Li- 

 chens, Hypoxyla, Fungi, Lycopodiacere, Mucedinea;, Uredineee, Fucacere, U1-. 

 vaceae, Ceramiaceae, Confervae, Chaodineae, and Arthrodieae ; part of which 

 have originated with himself, and others with M. Bory de St. Vincent. I think, 

 however, in the present state of our knowledge, it will be more prudent to ad- 

 mit only the three principal groups adopted by Agardh and Hooker ; and even 

 these are distinguishable by their general habit rather than by any very posi- 

 tive character of structure. Thus, Lichens are aerial plants, with distinct 

 spaces upon their surface, in which their sporules are contained ; Fungi differ 

 from Lichens only in their fugacity and want of external receptacles 'of spo-. 

 rules ; while Alga; are all aquatic. 



The structure of leafless plants is among the most important subjects of 

 contemplation for those who wish to become acquainted with the exact laws 

 of vegetation. They represent the organized matter, of which all other plants 

 are composed, both in its simplest state and when it begins to enter into a 

 state of high composition. In short, it is here only that the physical properties 

 of vegetable matter can be usefully studied. 



