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IOWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
Bischoff (1835) called the Nostoc colonies antheridia but a 
few years later Nees von Esenbeck found the real antheridia 
and called the Nostoc “ Keimkornerknotchen. ” Hofmeister 9 
held that the organs were reproductive buds, basing his idea on 
their analogy with what he called “the undoubted buds of An- 
thoceros” developing in the same manner. He says, “It is well 
known that numerous reproductive buds are formed on the under 
side of the stem of Blasia. The contents of one of the inner 
cells of the tissue of the stem (which cells are only separated 
from the under side by a single cellular layer) become trans- 
formed into a cell occupying the whole cavity of the mother- 
cell. This daughter cell changes into a roundish body, composed 
of small cubical cells which contain numerous very small chlor- 
ophyll bodies of a dark bluish-green color. The cellular layer 
of the under surface of the stem which covers the reproductive 
buds becomes swollen to a hemispherical shape by the increase 
in size of the latter. 1 have not seen these reproductive buds 
develop into young plants.” 
Corda 4 figures the germination of the Nostoc cells and calls 
them new plants of Blasia. These erroneous ideas were not cor- 
rected until Leitgeb’s work was published 1874. He gave a good 
description of the structure and origin of the peculiar chambers, 
but failed to show the fully developed auricle. Coker 3 says, 
“By pressing out the Nostoc he (Leitgeb) found that the colony 
was penetrated by clear cells, which he correctly deduces to be 
branches of the Blasia thallus that have arisen from the slime- 
secreting hair that was present in the young stages. There 
grows up from the. floor of the chamber a treelike structure with 
a single trunk, and from the repeated ramifications of this tree 
the whole colony becomes interwoven with cells which doubtless 
serve to abstract nourishment from the algae. This whole rami- 
fying structure has in all probability come, as Leitgeb thought, 
from the subsequent growth of the slime-secreting cell. In 
other cases of such symbiotic relationships, as Anthoceros, there 
are, likewise, cells growing in from the host plant ; but in all 
such cases, so far as I know, these outgrowths originate, not 
from a common base, but separately and at many points. The 
striking arrangement of Blasia seems to be confined to it alone.” 
The host plant cells no doubt take nourishment from the 
colonies of algae and they may also serve as water reservoirs as 
