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PACIFIC SCIENCE, Vol. IX, July, 1955 
the axial cell second below the fertile one also 
produces involucral branches (Fig. id). These 
all have the structure of axial filaments, 
though one commonly surpasses the rest. 
Post-fertilization stages follow a course 
typical for the Ptiloteae. The trichogyne is 
separated from the carpogonium by a septum 
and then collapses. The auxiliary cell is pro- 
duced from the adaxial side of the fertile 
pericentral cell, of which a small portion re- 
mains as a "basal cell," to use Oltmanns’ 
terminology (Fig. id). In these stages a cell 
is intercalated between the carpogonium and 
the third cell of the auxiliary branch. This 
suggests that it is here that carpogonium and 
auxiliary cell fuse by mediation of a con- 
necting cell produced by the former (Fig. 
Id, 2a). From the auxiliary cell three or four 
gonimoblast initials are produced, at least the 
first two developing into gonimolobes (Fig. 
2c). The basal cell of each gonimolobe cuts 
off carpospores but remains distinct as a long 
stalk cell, like a paler handle to the cluster of 
heavily pigmented spores. Such stalk cells are 
characteristic of the Crouanieae, the Carpo- 
blepharideae and at least Plumaria elegans 
among the Ptiloteae, but are not found among 
the presumably derived Ceramieae. 
At the same time that growth of the apex 
is arrested, a rhizoid grows down from each 
side of the axial cell above the fertile one, 
and another from the proximal cell of the 
long branch attached to the fertile axial cell 
(Fig. 2a). These rhizoids may become two- 
or even four-celled, and extend around the 
base of the cystocarp like the ribs of a skele- 
ton (Fig. lc, 2a). Feldmann-Mazoyer (1940) 
illustrated such rhizoids in Seirospora Giraudyi 
of the Callithamnieae. They seem a constant 
feature of the rhizoidally corticated Calli- 
thamnieae (and, oddly enough, of the uncor- 
ticated Compsoth amnion) but of Dasyptilon 
alone among the Ptiloteae, which are other- 
wise parenchymatously corticated. In Dasy- 
ptilon the fertile axial cell becomes almost 
continuous with the gonimoblast, by a broad- 
ening of the pit-connections of the basal cell, 
and may die after the release of the carpo- 
spores, thus detaching the distal, uncorticated 
part of the shoot. Feldmann-Mazoyer sug- 
gests that, in Seirospora Giraudyi , the rhizoids 
may serve to anchor the detached apex as a 
new shoot. At any rate thay cannot be of more 
fundamental phylogenetic significance than 
the occurrence of rhizoidal cortication. 
AFFINITIES OF DASYPTILON 
The taxonomic position of Dasyptilon as a 
member of the Ptiloteae has never been ques- 
tioned, but it has a number of features in 
which it is more referable to the Crouanieae, 
the tribe including the most generalized forms 
among the Ceramiaceae. In its distichous 
fronds, obliquely-dividing apical cell, rela- 
tively slight rhizoidal, non-parenchymatous 
cortication, and finally in the sessile lateral 
position of the tetrasporangia, it could be 
related to distichous species of Antithamnion 
among the Crouanieae. And these are the 
features on which Feldmann-Mazoyer dis- 
tinguishes it from the other Ptiloteae. In 
sexual reproduction it shows features rela- 
tively generalized among the Ceramiaceae and 
shared by the Crouanieae, producing carpo- 
gonial branches on the pericentral cells of a 
modified shoot which retains the potentiality 
of vegetative development and resumption of 
the vegetative form in the absence of fertiliza- 
tion or, presumably, if detached after dis- 
integration of the cystocarp. 
Kylin (1930) separates the Ceramiaceae into 
two subfamilies*, those with each procarp on 
a determinate axis, such as Spermoth amnion 
and Ptilota; and those with procarps borne 
along an indeterminate axis. Dasyptilon with 
several procarps on a facultatively determinate 
axis thus links the two groups. However, the 
distinctive vegetative features of the Ptiloteae 
are found in the regular alternation of long 
and short branches on the axis, and the dis- 
tinctive reproductive feature of the fertile 
pericentral cell producing carpogonial branch 
before sterile cell. Inasmuch as its features of 
specialization are those of the Ptiloteae, it 
