Nepenthaceae, a monotypic family of carnivorous pitcher plants comprising Nepenthes, is widely distributed in Southeast Asia. To determine the phytogeography of Nepenthes in Southeast Asia, and to trace the evolutionary trends of taxonomically important characteristics (i.e., peristomes) of the genus, we analyzed 57 internal transcribed spacer (ITS) nuclear ribosomal DNA (nrDNA) sequences of 56 species of Nepenthes and 1 ITS sequence each of Dionaea muscipula and Ancistrocladus robertsoniorum. To clarify the phylogenetic relationships of Nepenthes, we examined four different methods of phylogenetic tree reconstruction. The resulting tree topologies were mostly consistent with one another except for the basal polytomies. Seven monophyletic subclades could be recognized. Similarities and differences in terms of the positions of taxa between the present study and previous studies were observed. Judging from the phylogenetic trees and distribution area of each species, Borneo appears to be a secondary center of diversification for Nepenthes and species of Nepenthes may have then radiated within the Sunda Shelf of Southeast Asia. The three character states of the peristomes from the upper pitchers were relatively well correlated with the grouping of the species of Nepenthes within seven subclades and showed the limitations of the Danser (1928) system for Nepenthes.
Variation in several floral traits was examined to determine floral dimorphism in three populations of Psychotria serpens from Amami-Oshima and Okinawa islands, Japan. Two populations on Amami-Oshima exhibited long-styled and short-styled morphs that differed reciprocally from each other in stigma and anther heights, while a population on Okinawa was composed of long (L)-styled, short (S)-styled, and short homo (H)-styled morphs. In the L- and S-styled morphs, most flowers usually produced pollen grains stainable with aniline blue in lactophenol. Pollen grains from the S-styled morph were significantly larger than those from the L-styled morph, but no major difference was found between the two morphs in exine sculpturing. In the H-styled morphs, most flowers usually lacked pollen grains or did not produce stainable pollen grains. In some peculiar flowers, however, a few stamens that were exserted from the corolla tube rarely produced stainable pollen grains in the H-styled morph; the diameter of the pollen grains was in accordance with those of the S-styled morph. These observations suggest that P. serpens in the Ryukyu Islands is fundamentally distylous and sometimes includes short H-styled morphs within a population, the stamens of which are frequently abortive. Considering the nature of the peculiar flowers, the short H-styled morphs appear to be a consequence of unusual floral development.
In an effort to better understand phylogenetic relationships within Disporum (Colchicaceae), we conducted molecular analyses of 36 samples (13 species, two varieties and two forms) using the plastid sequences trnK, trnL-F, and atpB-rbcL. A strict consensus of the 72 most parsimonious trees obtained, which has an identical topology to the maximum likelihood trees, showed that a clade of D. smilacinum and D. viridescens was sister to the rest of the genus. In a clade composed of D. sessile, D. lutescens, D. nantouense, D. uniflorum, D. shimadae, and D. kawakamii, the former three species formed a subclade, while D. sessile var. sessile f. sessile from Kyushu, f. minus, var. micranthum, and D. lutescens were further grouped together. Disporum sessile var. sessile f. sessile from regions other than Kyushu, as well as D. nantouense, was excluded from this group. As D. lutescens differs greatly from D. sessile morphologically, they cannot be considered to be conspecific. Therefore, from a phylogenetic standpoint, two different species are possibly included under the name of D. sessile var. sessile f. sessile: one from Kyushu and the other from elsewhere. Disporum nantouense is possibly a variety of D. sessile. Disporum sessile var. micranthum Hatus., nom. nud. was validated.
A new wild species of banana Musa kamengensis Gogoi & Hakkinen, is described and illustrated. The species is abundant in a 250 sq. km area from Jamiri, Zero point to Kimi point along Sepa Road in West Kameng, Arunachal Pradesh, India. A key to the closely related species is provided.
Flowering individuals of a species of Gastrodia (Orchidaceae) with a closed perianth tube, a petaloid lip without appendages or calluses, and a column with a large, bifid ventral appendage were discovered in the northern part of Okinawa Island, Okinawa Prefecture, the Ryukyus. This combination of characters is known only in Gastrodia clausa, a recently described species from Taiwan. The characteristics of the Okinawan plants agree with the description of G. clausa. We therefore conclude that our plants represent the first record of G. clausa in Japan.
This paper reviews studies of the phylogeny and evolution of epiphytism in ferns, with an emphasis on Davalliaceae. The family forms the largest, generally epiphytic monophyletic clade with Polypodiaceae including grammitids. Several other lineages include epiphytes. Molecular phylogenies suggest that the davallioid-polypodioid epiphytes diverged from the secondary hemi-epiphytic Oleandraceae in angiosperm-dominated forests in the Paleogene. The evolution of epiphytism in vittarioids and lycophytic Huperzia may be derived directly from terrestrial ancestors. The stepwise evolution of epiphytes is characterized by the ecological shift of gametophytes from the ground to trees following sporophytes, while the abrupt evolution involves the simultaneous shift. Furthermore, reversals from epiphytes to secondary hemi-epiphytes or to terrestrial plants are also likely in other ferns. Precise identification of life forms in the field offers a sound basis of research on epiphyte evolution. There are several morphological traits correlated with life-form change (e.g., rhizome length and dorsiventrality; absorbing or adhering roots; peltate, stalked, dense scales), as well as physiological traits. Epiphytic gametophytes are strap-shaped, ribbon-like or filamentous, branched, gemmiferous and long-lived in, e.g., grammitids, Hymenophyllaceae and vittarioids, while, like terrestrial gametophytes, they are heart-shaped and monocarpic in, e.g., Davalliaceae and Polypodiaceae. Comparative eco-physiological research of gametophytes is needed to investigate the transitions from terrestrial to epiphytic gametophytes. Interactions between epiphytes and hosts should be clarified to understand the evolution of epiphytism. Mildly hemiparasitic epiphytes, e.g., Pyrrosia piloselloides (Polypodiaceae), probably obtain water and nutrition from their hosts and may represent a further step in the evolutionary sequence.