An Anatomical Study of the Hawaiian Fern 
Adenophorus sarmentosus 1 
Kenneth A. Wilson 2 and Fred R. Rickson 3 
The endemic Hawaiian fern, Adenophorus 
sarmentosus (Brack.) K. A. Wilson, occurs on 
all of the major islands, growing on moss- 
covered trees and occasionally also on mossy 
rocks. As a representative of the large but poorly 
understood fern family Grammitidaceae, A. sar- 
mentosus was chosen for anatomical studies in 
order to contribute some information on the 
family which may be of value in later systematic 
studies of the group. Anatomical or morpho- 
logical studies of the grammitids are rare. A 
series of recent papers by Nozu (1958-1960) 
presents the only anatomical investigation of 
members of this family except for a few notes 
published earlier by Ogura (1938). 
The plant material used was collected at Wai- 
anae Iki on the island of Oahu in 1954 by Earl 
T. Ozaki. A voucher specimen has been de- 
posited in the herbarium of San Fernando Val- 
ley State College. The fern was killed and fixed 
in F.A.A.; sectioning was done according to 
standard paraffin techniques. Leaves were cleared 
by the sodium hydroxide technique (Foster, 
1949) and stained in tannic acid and ferric 
chloride (Wilson, 1958). 
OBSERVATIONS 
The rhizome of A. sarmentosus is erect or 
ascending, short, usually less than 1 cm in length, 
0.5-1 mm thick, and clothed in reddish-brown, 
concolorous, linear-lanceolate scales (Fig. 1, 8). 
The roots are wiry, dark brown, and few- 
branched, often bearing propagules which de- 
velop into new plants (Fig. 1, 2). This vege- 
1 This project was supported by a grant from the 
National Science Foundation and by a summer re- 
search grant to the junior author from the California 
Foundation for Biochemical Research. Manuscript re- 
ceived October 19, 1964. 
2 Department of Biology, San Fernando Valley State 
College, Northridge, California. 
3 Present address : Department of Botany, University 
of California, Berkeley, California. 
tative means of propagation is known not only 
in A. sarmentosus, but also in the closely re- 
lated A. haalilioanus , and should be looked for 
in the rare A. pinnatifidns. Similar reproductive 
behavior has been reported recently in Aspie- 
nium plenum of Florida (Wagner, 1963). 
The petioles are short, less than 2 cm long, 
crowded on the rhizome, and bearing simple or 
branched deciduous, reddish-brown hairs. The 
blades are pinnatifid, elliptic-lanceolate, 8-15 cm 
long, 1-2.5 cm wide, and narrowing gradually 
at both ends, often becoming prolonged into a 
long caudate apex (Fig. 1, 3). The venation is 
pinnate, with free simple (rarely branched) 
veins with clavate or punctiform ends which do 
not extend to the margins of the blade (Figs. 
1, 3 and 4). 
The outline of the stem is almost a perfect 
circle in cross-section. The vascular cylinder is 
protostelic in the young stages and becomes 
solenostelic in older portions of the rhizome. 
During the transition from the protostele, a 
parenchymatous pith develops (Fig. 2, 1), 
within which a central phloem strand differen- 
tiates in slightly later stages (Figs. 2, 2 and 3). 
In the older portions of the stem the inner 
phloem of the solenostele is cylindrical and sur- 
rounds a central pith (Figs. 2, 13-17). The single 
leaf traces which arise from the main stele and 
lead to the leaves are surrounded by the scleren- 
chyma of the cortex which extends into the 
petiole itself. Each leaf trace is generally asso- 
ciated with two root traces which arise either 
below the juncture of the leaf trace with the 
stelar gap (Figs. 2, 2-3 ) or somewhat above 
this level (Figs. 2, 7, 29, 30). One instance was 
observed in which a leaf gap was associated with 
only a single root trace which arose directly 
opposite the gap rather than perpendicular to 
the plane of the gap (Fig. 2, 21). Not all 
roots, however, arise in association with leaf 
traces. Pairs of root traces were observed de- 
parting from the main stele in regions between 
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