330 



Tribe III. APHYLL^, or LEAFLESS 

 FLOWERLESS PLANTS. 



AcotyledonEjE, Agardh Aph. 72.(1821). — Homonemea, Fries Syst. Orb. Veg. 33. 



(1825) AcoTYLEDONES, Class I. Ad. Brongn. in Diet. Class. (1824) 



Cryptogamic/E, 3d Circle, T. F. L. Nees v. Esenbeck 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 sub- 

 stance 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 sexes, 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 Algae where water is the medium in which it is developed. The 

 nearest approach to animals is in the tribes of Algse called Arthrodiese and 

 Chaodinese, where it is perhaps impossible to decide whether some of the 

 species 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.. Algae, including Lichens 

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

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

 Lichens from Alg'ce, which, indeed, was virtually done by most of those who 

 acknowledged but two divisions, and with admitting three equally distinct 

 groups. Some, 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 Epiphytoc, 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. Lichens, Hypoxyla, Fungi, Lycopodiacese, Mucedineae, Uredineae, 

 Fucaceac, Ulvaceae, Ceramiaceae, Confervae, Chaodineae, and Arthrodieoe ; 

 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 admit only the three principal groups adopted by Agardh 

 and Hooker; and even these are distinguishable by their gcTieral habit rather 

 than by any very positive 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 sporules; 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 organised matter, of which all other plants 

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



