Chang Yong-Tian, Huang Cheng-Chiu
1988, 26 (2): 111–119
This is the second paper under the same topic (cf. Bull. Bot. Res.6(2): 101-106, 1986) as materials for compiling Fl. Reip. Pop. Sin.
There are 7 species of Fagus found in China, but whether two of them, F. tientaiensis, F.
chienii, can stand steadily or not is doubtful. Lacking sufficient available materials at hand,
the matter would better be left for a further study.
F. hayatae, F. pashanica and F. tientaiensis are so closely alike among them that differences seem exist only in quantitive characters such as size of leaves, duration of indumentum and
less gap in length of the cupules and their peduncles. Considering some criteria, they may be
treated as geographical races belonging to a single species.
Diverse morphological interpretations concerning the nature of the cupule together with
its coverings by terms of spines, scales, bracts or bracteoles, lamellae etc., have been put forward
by the previous authors.
Brett (1964), Abbe (1974), Macdonal (1979) and the others have given rational interpretations but only to the cupule, and Fey & Endress (1981, 1983) have made further studies although materials they used for the observation are only three species representing three different genera. Their elaborate works on anatomical evidence from reproductive parts came at
a conclusion of critical importance which has reached a more reasonal interpretation than the
others before. “the cupular valves represent the outermost modified, sterile branches of the
cymose partial inflorescence”, while Forman’s (1966) interpretation of the organ is “The
cupule can be regarded as wholly axial orgin”. Furthermore, a similar but more detailed speculation had been given previously by Trelease(1924): “the acorn cup is constituted by the
fused secondary branches of a dichasium”.
The problem here turns to the views on the nature of their coverings around the outer wall
of the cupule, those various terms have been used for the coverings just given above. Some
authors (Forman 1966, and the others) called them “emergences”, “appendages” collectively.
Although Forman (1966 pp. 411-412) has pointed out some aspects of morphological and
anatomical resemblance between scales and leaves when he says “especially in Fagus orientalis
Lipsky, the appendages may in their nervation resemble small leaves”, he still doubt if “the
scales of Quercus and Lithocarpus have evolved from leaves”. Fey & Endress (1981, p. 179,
abb. 95.3) gave only a figure and called it “blattartige schuppen”, but no description concerning the phenomenon in the whole text.
The second example was observed by the present authors. The cupule of Fagus engleriana
Seem. bears the lower rows of “bracts” much like the leaves from which they differ only in
diminitive form and size. Not only do they possess a complex netted nerved system, but they
also contain chloroplast (greenish color even in dried status), which suggests that scales or
appendages be real leaves in origin. The various forms of so called bracts or appendages just
given above, have been highly modified from leaves through a long history of evolution.
This interpretation is also adoptable to all the other genera of the family Fagaceae.
The modification of leaves, spines, tubercles, scales and even rings might be due to theiradaptation to new or changed environments.