Endocarps of menispermaceous plants in Taiwan
Yang and Chen Bot Stud
Endocarps of?menispermaceous plants in?Taiwan
Sheng?Zehn Yang 0
Po?Hao Chen 0
0 National Pingtung University of Science and Technology , No. 1, Shuefu Rd., Neipu, Pingtung 912 , Taiwan
Background: The fruits of the family Menispermaceae are drupes, and because the drupe endocarps are morphologically diverse, they are generally used to classify members of this family. There is a lack of detailed knowledge of Menispermaceae endocarps in Taiwan. Therefore, in this study, the endocarps of seven genera and 14 species were dissected, and their morphological characters were photographed and described. Furthermore, a key for the 14 species based on the endocarps features, as well as a key of the studied genera, is proposed. Results: The endocarp types comprise a straight shape in Tinospora dentata Diels and a horseshoe shape in the other 13 species. In general, the genus Cyclea bears two dorsal crests with 16 small spines, although there are about 25 spines in Cyclea insularis (Makino) Hatusima. The genus Cocculus has a dorsal convex endocarp with a subannular. In Taiwan, the endocarp of Sinomenium acutum (Thunb.) Rehder & E. H. Wilson has up to 26 transverse ridges, without spines on the crest and might be categorized under the genus Menispermum. Transverse endocarp ridges are found in Stephania cephalantha Hayata and Stephania tetrandra S. Moore, whereas transverse endocarp strips are found in Stephania japonica (Thunb.) Miers, Stephania longa Lour. and Stephania merrillii Diels. Conclusion: We believe that the descriptions and photographs of the endocarp traits of T. dentata, which is endemic to Taiwan, will provide more evidence for further studies on extant and fossil species.
Condyle; Classification; Dioecious climbing plants; Mesocarp; Moonseed family
Background
The Menispermaceae is a diverse family of mostly dioecious
climbing plants, consisting of a few tree species, but mostly
shrubs, and herbs. There are 72 genera and 520 species in
this family
(Jacques et? al. 2011; Wang et? al. 2012)
, and the
most speciose genera include Cissampelos L. (20?30 spp.),
Cyclea Arn. ex Wight (30 spp.), Stephania Lour. (30?60
spp.), and Tinospora Miers (25?35 spp.) (Wefferling et? al.
2013). Most members of this family are distributed
throughout the tropics, although some are found in temperate
regions. Their endocarps appear often in fossil records, and
they indicate the presence of a wet forest ecosystem
(Herrera et?al. 2011)
. About 116 species in this family were
surveyed for their endocarp traits by
Jacques (2009)
.
Menispermaceae leaves are typically simple, with a
palmatinerved venation, although a few genera have a pinnate
venation. Their leaves are subpeltate, with a few taxa?s leaves
being strongly peltate, with pulvinate petioles at both ends.
Menispermaceae inflorescences and infructescences are
mostly determinate; axillary, or borne on defoliate branches
or old wood, rarely terminal; solitary or fasciculate; occur
most often in racemes, cymes, or thyrses, sometimes in
panicles or cymose heads, rarely reduced to solitary flowers
(Wefferling et?al. 2013)
. Flowers are unisexual,
inconspicuous, trimerous, and actinomorphic; a few genera have
pistillate, zygomorphic flowers; carpels are free, usually range
between three and six in number, whereas the zygomorphic
genera only have a single carpel; stamens are mainly free,
but some genera form a synandrium
(Ortiz et? al. 2007)
.
Fruits are produced aggregates of 3 or 6, single-seeded, and
sometimes stipitate drupes. They usually consist of a fleshy
or fibrous mesocarp, and a bony, woody, coriaceous,
chartaceous or papyraceous endocarp.
The dorsal portion of the fruit in this family is mostly
convex. Otherwise, it grows in a gibbous manner that
curves the fruit into a horseshoe or crescent-shape, with
the style scar becoming basal or sub-basal, appearing in
mature fruit close to the pedicel. Otherwise, if the fruit
is not curved, the style scar may be apical. Many
endocarp characters vary within the family, such as endocarp
type, limb length, condyle shape, convex or concave
dorsal face, chambers, vascular trace, aperture, and
perforation. Because this family is mainly defined by the curved
seed found in many of the genera, it is also known as the
moonseed family.
Menispermaceae endocarps vary widely in their
ornamentation, which provides important taxonomic
characters for distinguishing between and within the
genera. Six genera and 13 taxa (including one variety) of
this family have been identified in the Flora of Taiwan
(Huang and Huang 1996)
, but exhaustive information on
Menispermaceae endocarps is still lacking. This lack of
data is addressed in this study, using their diverse
endocarp ornamentation, by (1) carefully revising the various
endocarp descriptors and providing detailed
photographs of the discussed features, (2) developing a key
based on endocarp morphological characters to identify
the Menispermaceae genera (...truncated)