THALLOPHYTES OR THALLOGENS. 7 
But these cells are all more or less alike, so that no true distine- 
tion can be drawn between the often very different looking parts 
we meet with in such 
plants as a sea-weed or Fig. 3. Fie. 4. 
a mushroom. Such a 
combination of similar 
cells, whatever the 
precise form may be, 
which presents no dif- 
ferentiation of leaf, 
stem, and root, is called 
a thallus or thallone, 
and every thallus-pro- 
ducing plant is there- 
fore termed a Thal- 
lophyte or Thallogen. 
Under the head of 
Thallophytes we com- Fig. 3. A species of Mou'd (Mucor), with branched 
: : mycelium (hyphal tissue or hyphe) below, from 
prise all those simpler which two stalks are seen to arise, each of which 
forms of plants which is terminated by asac (sporangium or ascus), from 
are commonly known which a number of minute bodies (spores) are 
Al Li 4 ae escaping.—Fiig. 4. Another Mould (Penicillium 
as Se, ichens, all glaucum), with branched mycelium (hyphal tis- 
Fungi. sue), and a stalk bearing several rows of cells, 
which are the germinating spores (conidia). 
Bre. 5. 
; Fig. 6. The common Mushroom (Aga7icus 
Fig. 5. Thallus or thallome of campestris). There are three receptacles 
the common Bladder Sea-weed ( fructification), arising from the mycelium, 
(Fucus vesiculosus). t, t. The my, below : one young and nearly globular, 
fructification. v, v. Bladders of and two mature. a. Pileus. 0. Lamelle, c. 
air. Annulus. 
Again, as all Thallophytes are composed of cells which 
