Anatomy of H esp ero mannia — CARLQUIST 
Fig. 3. Lower surface of mature leaf of Hesperoman- 
nia arbuscula subsp. oahuensis ( Hillebrand 1871), X 140. 
Numerous sclerified hairs may be seen above the vein 
reticulum. 
peduncle size or structure occurs. A peduncle 
of H. arborescens subsp. Bushiana , shown in 
Figure 4A, is typical in its numerous bundles 
and sclereid nests. Trichomes are persistent on 
the epidermis of peduncles in these two spe- 
cies. Hesperomannia Lydgatei , on the contrary, 
shows peduncles much smaller in diameter. 
This smaller stature is reflected anatomically 
in the fewer bundles present in the vascular 
cylinder and in the much smaller size of the 
pith (Fig. 4B). In addition, no hairs are pres- 
ent on the peduncle epidermis of H. Lydgatei , 
which is covered by a prominent cuticle. 
Involucral Bracts 
As in peduncle anatomy, the involucral 
bracts of plants belonging to H. arbuscula and 
H. arborescens are comparatively uniform in 
anatomical structure. As shown for H . ar- 
borescens subsp. Swezeyi in Figure 4C, a thick 
region of subhypodermal fibers occurs near 
the outer face of the bract in these species. 
Epidermal and hypodermal cells on this sur- 
209 
face remain thin-walled. This zone of fibers 
may be as many as 14 cells in thickness. On 
the interior face of the bract, a thinner band 
of fibers is present. The adaxial epidermis is 
most heavily sclerified, with decreasing wall 
thickness on the two or three cell layers in- 
terior to it. Between the fibers on the inner 
and outer faces of the bract, a region of thin- 
walled parenchyma is present. A single series 
of vascular bundles occurs in this region. The 
thickness of this central parenchyma band is 
greatest near the base of the bract and de- 
creases toward the apex. 
Inner involucral bracts show an altered form 
of this structure in the two species, as the 
bract of H. arborescens subsp. Bushiana in 
Figure 4D demonstrates. In such a bract, the 
region of parenchyma between the two bands 
of fibers is greatly narrowed. The bundles 
occur at points within the outer band of 
fibers, rather than in the parenchyma. The 
outer band of fibers is continuous, or nearly 
so, and encases most of the bundles. 
The involucral bracts of H. Lydgatei show 
a structure comparable only to the inner in- 
volucral bracts of the other species. Bundles 
occur only in interstices between the strands 
of fibers, which never form a continuous 
band as they do in the bract of H. arborescens 
subsp. Bushiana described above. 
Corolla 
As is typical for Compositae, a pair of 
lateral veins, which fuse beneath each sinus, 
is present in each corolla lobe in Hesperoman- 
nia flowers. In addition, median veins, such 
as shown in Figure 4F, were found to be 
present in both subspecies of H. arbuscula as 
well as in H. arborescens subsp. Swezeyi . Such 
median veins are present in one to three of 
the larger corolla lobes of a flower in these 
taxa, or are absent in some flowers. Where 
present, they extend for varied distances in 
the lower portion of the lobe. No median 
veins were found in the taxa not mentioned. 
Fibers encase the upper extent of the lateral 
veins of corolla lobes (Fig. 4F, G) in all 
