188 DIVISION IL—COURSE OF DEVELOPMENT OF FUNGI, 
latter are placed perpendicularly to the surface of the hymenium, and terminate at 
a uniform height on this surface, being crowded together in great numbers and 
usually giving the hymenial layer its characteristic tint from the colouring of their 
walls, or contents: not infrequently, especially in the hymenia of the Lichen-fungi, 
they are united laterally and without gaps by the gelatinously thickened walls, so that 
their lumina appear to be set in a homogeneous structureless jelly. The paraphyses 
spring by their inner or lower extremities, that is, those turned away from the outer 
surface as branches from a dense hyphal tissue beneath the hymenium, the subhymenzal 
layer or hypothecium, which is then continued further downwards into the more 
or less largely developed receptaculum or stipe of the apothecium, or at least 
into an outer envelope, the exczpulum, which belongs to it, though it is not greatly 
developed. 
The paraphyses, together with the elements of the hypothecium which produce 
and bear them and the receptaculum or excipulum, belong to the envelope-apparatus 
of the apothecium. But the ascogenous hyphae take their course in the hypothecium, 
being interwoven with the ele- 
ments of the envelope; they 
grow up in the commencing 
apothecium from points of 
origin, which will be described 
more exactly in section LXIII, 
in the direction of the hymenial 
layer, and afterwards spread 
themselves out near the under 
surface of the disk with copious 
branching which follows the 
progressive growth of the whole . 
apothecium, and thrust the 
FIG. 87. Anaptychia ciliaris. Médian section through an apothecium; A hy- its 7 
inp teed ee ae cae All bests bene to thet, extremities of their branches 
which forms a rim round the excipulum at ¢; 7 medullary layer, » rind, g its ae. 1 
After Sachs. Magn, about so times. eits Algae’ of the last order successively 


in between the paraphyses to 
form the asci. In many of the species belonging to this division the ascogenous 
hyphae can scarcely be distinguished from the elements of the envelope which 
surround them by anything but the formation of asci which belongs to them only. 
In others, especially in many but not all the Lichen-fungi, in which Schwendener 
first discovered them, they are distinguished from the surrounding tissue by their greater 
thickness, by the abundance of their protoplasm, and by their membrane turning 
blue after treatment with potash. The development of the envelope-apparatus 
is always in advance of the ascus-apparatus, though the latter may have begun to be 
formed at the same time; the paraphyses are therefore always the parts which 
are first present in the hymenium. The asci make their appearance after them 
and grow vertically upwards between them in the direction of the surface, reaching 
it usually or rising above it only as the spores become ripe (see section XXII). 
Only a few asci appear at first, then their number increases through successive 
branching of the ascogenous hyphae, often to such a degree that the paraphyses 
are displaced and become indistinguishable. 
