EXPLANATION OF TERMS. 
Membranous layer. 
branous mycelium. 
Membranous mycelium. Mycelium in 
which the hyphae form by interweaving 
a membranous layer. Same as mem- 
branous layer, myceliallayer. Comp. 
filamentous mycelium, membranous 
mycelium. 
Mentagra parasitica. Same as sycosis. 
Merispore. Segment of a sporidesm. 
Meristem. Actively dividing cell-tissue. 
Meristematic. Consisting of meristem. 
Meristogenetic. Produced bya meristem. 
Metabolism. The chemical processes 
inseparably associated with the vital 
activity of protoplasm. 
Metoecious. Forms which pass through 
separate sections of their complete de- 
velopment upon different hosts are me- 
toecious. Same as metoxenous, hete- 
roecious. Comp. autoecious, lipo- 
xenous. 
Metoxenous. Same as metoecious. 
Microcyst. In Myxomycetes: a resting 
state of the swarmcells. 
Microgonidium. Small gonidium com- 
pared with others produced by the same 
species. Comp. macrogonidium. 
Micropylar. Belonging to the micropyle. 
Microsoma. Small granule embedded 
in the hyaline plasm of protoplasm and 
constituting an essential portion of its 
substance. 
Monoecious. Having male and female 
organs on the same individual. Comp. 
dioecious. 
Monopodium. An axis of growth which 
continues to grow at the apex in the 
direction of previous growth, while lateral 
structures of like kind are produced 
beneath it in acropetal succession. Comp. 
dichotomy, sympodium. 
Multilocular spore. Same as sporidesm. 
Muscardine. Disease of the silkworm 
caused by Botrytis Bassii. 
Mutualism. Symbiosis in which two 
organisms living together mutually and 
permanently help and support one an- 
other. 
Mycelial layer. 
mycelium. 
Mycelial strand: See fibrous mycelium. 
Mycelium. Vegetative portion of thallus of 
Fungi composed of one or more hyphae. 
Mycetogenetic. Produced by Fungi. 
Mycetogenetic metamorphosis. Defor- 
mation of parts due to Fungi. 
Mycosis. A disease of animal tissues due 
to the vegetative activity of species of 
Eurotium. 
Myxamoebae. In Mycetozoa: swarm- 
cells with purely amoeboid creeping 
motion, 
[4] 
Same as mem- 
Same as membranous 

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Neck. In Pyrenomycetes: conical or 
cylindrical prolonged apex of pyrenocarp 
through which runs the canal leading to 
the ostiole. Same as tubulus. 
Nucleus. See kernel. 
Obligate. Necessary, essential. Comp. 
facultative. 
Obligate parasite. An organism to which 
a parasitic life is indispensable for the 
attainment ofits full development. Comp, 
facultative saprophyte, facultative 
parasite. 
Ontogeny. Development of an individual. 
Oogamy. Conjugation of two gametes of 
dissimilar form. Comp. isogamy. 
Oogonium. Female sexual organ usually 
a more or Jess spherical sac, without the 
differentiation into neck and venter of 
archegonium, and containing one or 
more oospheres (ova). The oospore does 
not divide to form a proembryo within 
the cavity of the oogonium on the parent 
plant. 
Oosphere (egg, ovum). Naked nucleated 
spherical or ovoid mass of protoplasm 
which, after its nucleus has coalesced 
with the sperm nucleus, developes the 
oospore. 
Oospore. Immediate product of fertilisa- 
tion in oosphere. 
Ostiole (ostiolum). In Pyrenomycetes: 
aperture in pyrenocarp through which 
discharge of spores takes place. Same 
as pore. 
Outer peridium. See peridium exter- 
num. 
Ovule. In Phanerogams: macrosporan- 
gium. 
Panicle. Twice or more branched struc- 
ture in which the base of each branching 
is elongated. 
Paniculate. Having the form of a panicle. 
Paraphyses-envelope. In Uredineae: 
same as peridium. 
Paraphysis. Sterile capilliform hyphal 
branch accompanying spore-mother- 
cellsina hymenium. Applied by Phoebus 
especially to a cystidium. 
Parasite. Organism living on or in and 
at the expense of another living organism 
(host). Comp. saprophyte. 
Parthenogenesis. Form of apogamy in 
which the oosphere (ovum) itself de- 
velopes into the normal product of 
fertilisation without a preceding sexual 
act. 
Pathogenous. Producing disease. 
Pébrine. Disease of the silkworm 
caused by Nosema Bombycis, Nag., 
a bacterioid organism. Same as gat- 
tine. 
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