ENDOMORPHIC AND ECTOMORPHIC CHARACTERS IN PELECYPHORA AND ENCEPHALOCARPUS

Boke , Norman H. (U. Oklahoma, Norman.) Endomorphic and ectomorphic characters in Pelecyphora and Encephalocarpus. Amer. Jour. Bot. 46(3) : 197-209. Illus. 1959.—Outstanding ectomorphic characters of Pelecyphora valdeziana include its small size; pectinate, hairy spines; broad, truncate, floral buds; dehiscent, berry-like fruits; and black, tuberculate seeds. The leaves are vestigial, and although the areole meristem originates on the adaxial face of the tubercle primordium, it is soon elevated to the summit by intercalary growth. The first primordium of the single, elliptical series of spines is initiated immediately in front of the rudimentary leaf. Others form in acropetal sequence on either side of the areole meristem. The last ones form across the areole, leaving a meristem, which may be floral or vegetative, on the anterior side. Whether areoles of P. valdeziana can be considered dimorphic is doubtful. However, they approach the type of dimorphism found in Epithelantha. Pelecyphora aselliformis has acuminate floral buds; dry, papery fruits; and brown, curved, reticulate seeds. The leaves are reduced almost to extinction. The areole meristem becomes separated into spiniferous and axial portions early in ontogeny, but the 2 parts remain connected by a band of trichomes, which probably represents a vestigial groove. The axial meristem may be reproductive or vegetative. The sequence of spine initiation in P. aselliformis is unusual in that it begins at the anterior side of the spiniferous meristem and proceeds toward the posterior side. Areoles in this species are clearly dimorphic, much as in the mammillarias, but the vestigial groove is reminiscent of Coryphantha and related genera. Although adult specimens of Encephalocarpus strobiliformis bear scale-like tubercles, which are very different from the laterally compressed tubercles of P. aselliformis, their flowers, fruits, and seeds are almost identical. The two species share the same type of areole dimorphism, including the vestigial groove. Tubercles on seedlings and young branches of E. strobiliformis are prismatic rather than scale-like. Since they tend to be laterally compressed at the summit and bear elliptical areoles with many more spines than the adult, they resemble seedling tubercles of P. aselliformis. Tubercles on adult specimens likewise resemble each other in the structure of the epidermis and hypodermis. It does not seem possible that P. valdeziana can be retained in the genus Pelecyphora. If seed structure has any systematic value, the species belongs in or near the genus Thelocactus, to which it was assigned by Bravo. Pelecyphora aselliformis and Encephalocarpus strobiliformis, on the other hand, share so many important characters that they could well be considered cogeneric. Both seed structure and the rudimentary grooves on the tubercles suggest that their affinities may lie with certain coryphanthas or mammillarias rather than with Ariocarpus and Epithelantha.     

A REVISION OF ARIOCARPUS (CACTACEAE). I. THE STATUS OF THE PROPOSED GENUS ROSEOCACTUS

Anderson, Edward F. (Claremont Graduate School, Claremont, California.) A revision of Ariocarpus (Cactaceae). I. The status of the proposed genus Roseocactus. Amer. Jour. Bot. 47(7) : 582–589. Illus. 1960.—The proposed genus Roseocactus Berger is found to be a subgenus of Ariocarpus. The subgenera Ariocarpus and Roseocactus are basically similar in habitat, seedlings, presence of mucilage systems, tubercle structure, seed structure, fruiting habit, flower origin and structure, alkaloidal properties, trichomes, pollen grains, and chromosome number. They differ in flower color, presence or absence of an areolar groove, tubercle divergence, and trichome texture. A hypothesis is proposed to explain variations in the areoles. The differences in structure of mature tubercles are thought to be due to variability in the location of growth and elongation with respect to the floral and spinous areolar areas.     

How and why does the areole meristem move in Echinocereus (Cactaceae)?

Background and Aims In Cactaceae, the areole is the organ that forms the leaves, spines and buds. Apparently, the genus Echinocereus develops enclosed buds that break through the epidermis of the stem adjacent to the areole; this trait most likely represents a synapomorphy of Echinocereus. The development of the areole is investigated here in order to understand the anatomical modifications that lead to internal bud development and to supplement anatomical knowledge of plants that do not behave according to classical shoot theory.Methods The external morphology of the areole was documented and the anatomy was studied using tissue clearing, scanning electron microscopy and light microscopy for 50 species that represent the recognized clades and sections of the traditional classification of the genus, including Morangaya pensilis (Echinocereus pensilis).Key Results In Echinocereus, the areole is sealed by the periderm, and the areole meristem is moved and enclosed by the differential growth of the epidermis and surrounding cortex. The enclosed areole meristem is differentiated in a vegetative or floral bud, which develops internally and breaks through the epidermis of the stem. In Morangaya pensilis, the areole is not sealed by the periderm and the areole meristem is not enclosed.Conclusions The enclosed areole meristem and internal bud development are understood to be an adaptation to protect the meristem and the bud from low temperatures. The anatomical evidence supports the hypothesis that the enclosed bud represents one synapomorphy for Echinocereus and also supports the exclusion of Morangaya from Echinocereus.     

云南鸡脚连(小檗科)的变异式样

小檗属鸡脚连(Berberis paraspecta Ahrendt)自1961 年发表以来,已有分类学文献对该种的描述一直模糊不清。通过在云南省玉龙县玉龙雪山野外调查与居群取样,结合模式标本核查,对鸡脚连重要分类学性状特征进行了补充和订正。鸡脚连果实1~5 个簇生,平均为(2.23±1.18)个;幼果或子房内胚珠1~3 个,平均为(2.07±0.29)个;成熟果实紫黑色,无粉霜,种子1~3 个,平均为(1.77±0.44)个。研究结果表明,有关文献关于鸡脚连果实单生,且仅含1 粒种子等关键的特征描述,在鸡脚连野生居群及模式标本上都不存在, 同时分析了鸡脚连果实、种子及胚珠数目、叶片及叶刺等分类学性状特征的变异系数,并补充了活植物及模式标本的图片资料。     

Fruit features in relation to the ecology and distribution of

Fruit features of 17 Acaena species in New Zealand were investigated to determine the relations between reproductive allocation patterns, mode of dispersal and species ecology. Three basic morphological types, corresponding to major sections within the genus, are represented: spineless fruits (Sect. Pteracaena—one species), spined fruits lacking barbs (Sect. Microphyllae—6 species), and spined fruits with barbs (Sect. Ancistrum—10 species). The presence of terminal barbs on spines enhances fruit adhesion to animals, and is associated with the development of longer scapes, globular many-fruited capitula, and smaller single-seeded fruits. Barb-spined species generally have the broadest geographical range and habitat distribution within New Zealand, and are the only species of Acaena to occur in forests or on offshore islands. These species are generally strongly stoloniferous. Acaena species with barbless spines and/or no spines are often regional endemics confined to open and/or localised habitats, are rhizomatous, and may be dispersed by water, ingestion or wind. There is a tight correlation between intrageneric classification and species ecology and fruit features which requires testing via independent phylogenetic analysis based on molecular genetic characters. Although avian dispersers have declined since human settlement, introduced mammals may be performing a similar function for barbed Acaena species.     

AREOLE DIMORPHISM IN CORYPHANTHA

Boke , Norman H. (U. Oklahoma, Norman.) Areole dimorphism in Coryphantha. Amer. Jour. Bot. 48(7): 593–603. Illus. 1961.—Coryphantha clava and C. erecta have both grooved and grooveless tubercles. The latter occur on young plants and emergent branches and may occur mixed with grooved tubercles on adult shoots, especially in C. erecta. Grooved tubercles have monomorphic areoles and are the only ones which bear flowers. The dimorphic areoles on grooveless tubercles develop exactly as in the mammillarias. In both species capitate glands occur in the axils of most tubercles and may occur at any position along an areole groove. The glands are initiated by the areole meristem in the same manner as spines, with which they are homologous. Close relationship between the 2 species is substantiated by both ectomorphic and endomorphic characters. The possession of both monomorphic and dimorphic areoles may mean that these cacti are evolving toward the complete areole dimorphism manifested by the mammillarias.     

中国柿树科植物一新记录种——长柱柿(英文)

报道中国柿科(Ebenaceae)柿属植物一新记录种——长柱柿(Diospyros brandisiana Kurz),并描述了该新记录种的形态特征和生境分布。该种为该属中国分布的唯一具老茎生花的种类。凭证标本存放于中国科学院昆明植物研究所标本馆(KUN)。     

STRUCTURE,DEVELOPMENT, AND TAXONOMY IN THE GENUS LOPHOPHORA

Structural and developmental data indicate that Lophophora (Cactaceae) should be retained as a genus, which appears to be most closely related to Thelocactus (sensu lato). Within Lophophora morphological differences suggest that two species should be recognized. In the extensive northern population (Texas along the Río Grande to San Luis Potosí in Mexico) the tubercles are usually arranged as distinct ribs or elevated podaria, whereas in the restricted southern population (limited to the Mexican State of Querétaro) podaria and ribs are poorly developed or lacking and there are also differences in pollen structure. We believe that these two populations should be recognized as distinct species, L. williamsii and L. diffusa, respectively. We further believe that the latter represents the ancestral type.     

A new species of Euryrhynchus Miers, with a discussion of the systematic position of the Euryrhynchidae Holthuis (Crustacea, Decapoda)

A new species of the South American freshwater genus Euryrhynchus, E. tomasi sp. nov., is described on the basis of two specimens from French Guyana. The new species differs from all its congeners by the presence of two disto-lateral spines on the merus of the second pereiopod, combined with the absence of any carpal spines. The recent elevation of the euryrhynchids to family status is supported, whilst a discussion is presented of their systematic position and affinities, emphasising the remote systematic affinity with the Typhlocarididae, previously assumed to be closely related. An appraisal of the systematically important characters in the Euryrhynchidae highlights the need for a re-appraisal of the caridean superfamily Palaemonoidea.     

Studies on the leaf anatomy of Euphorbia: II. Venation patterns*

Leaf venation patterns of 150 species of Euphorbia are presented and their value as a diagnostic feature in the genus assessed. Based on the gross venation patterns, the species have been grouped into uni-, bi-, tri-veined and special categories. The majority of the species studied belonged to the tri-veined category, in which ornamentation of the veins and the course of traces in the lamina proved useful additional characters. Features such as the size of the areoles, the number of vein endings, and their further ramifications and composition in each areole varied in the same leaf or in different leaves of a given species. Furthermore, no direct correlation could be established between the areole size and the numbers of vein endings and tips per areole. Forty species possess a parenchymatous vein sheath. Globular chloroplasts showed up conspicuously in the sheath cells of a few species. Dilated tracheidal elements, localized on the venules or at the tips of vein endings, are characteristic of the xerophytic species. In some instances, correlation was apparent between plants grouped according to their venation patterns and their habit.     

Taxonomic significance of spine morphology in the echinoid genera Diadema and Echinothrix

Abstract. The spine morphology of all established species of Diadema and Echinothrix, including 2 color morphs of E. calamaris, were examined externally and internally via transverse sectioning to identify diagnostic species features and to assess the morphological relationship between species. Forty‐nine different morphological characters were measured and analysed using ordination by multi‐dimensional scaling (MDS) and cluster analysis. Specimens of Diadema paucispinum and D. setosum had very distinct spine structures. In D. paucispinum, the spines were more robust than those of other species of Diadema. This was evident in the spine's internal structure, with large, closely packed solid wedges, a small axial cavity, and rings of trabeculae throughout the spine's length. The spines in D. setosum were distinctive because of their length in relation to test size and the reduced flaring of their verticillations. The spines of other members of this genus were very similar to each other. Without careful sectioning, the spines from specimens of D. antillarum, D. ascensionis, D. mexicanum and D. savignyi were difficult to differentiate. The internal structures of spines for each species did, however, possess a combination of features that differentiated the species. Such features included the shape, orientation, and number of solid wedges, the presence or absence of spokes and rings of trabeculae between the solid wedges, and the presence or absence of tissue within the axial cavity. Individuals of Diadema palmeri also had spines morphologically similar to other species, however, the red pigmentation of these spines (in life and when preserved) made them easily distinguishable. The spine structures of the 2 species of Echinothrix were starkly different, while the white and brown color morphs of E. calamaris had morphologically distinctive ambulacral and interambulacral spines. The blunt, open‐tipped interambulacral spines, with reticular tissue present in the axial cavity of the white color morph, were easily distinguished from the pointed, closed‐tipped spines, with a hollow axial cavity found in the brown color morph. Such differences indicate that the brown color morph is either a subspecies or a separate species. Taken together the data show that each species has significant morphological differences in the structure of the spines. It is evident from our data that spine morphology is a useful tool to differentiate these commonly confused species.     

COMPARATIVE ANATOMY AND SYSTEMATICS OF WOODY SAXIFRAGACEAE: TETRACARPAEA

Vegetative and reproductive anatomy and morphology are described for the first time for Tetracarpaea tasmannica Hook., a small shrub endemic to Tasmania. Tetracarpaea, a monotypic genus, has many characteristics of other woody Saxifragaceae, such as wood with solitary pores, scalariform perforation plates, sparse axial xylem parenchyma, tracheids, spiral thickenings in tracheary elements, and perforated ray cells. The tracheary elements of Tetracarpaea are much smaller than those characteristic of the Escallonioideae, a feature probably related to its montane forest habitat. Other features of Tetracarpaea inconsistent with most Escallonioideae include dark-staining deposits in the ray cells; a unilacunar, one-trace nodal pattern; lack of unicellular foliar trichomes; simple craspedodromous venation; areole development that is lacking or incomplete; straight and tapered veinlets; abaxial fibers associated with the foliar vascular bundles; and lack of bundle sheaths. The genus is further characterized by complete, hypogynous, tetramerous flowers. The essentially apocarpous gynoecium has multiovulate carpels, each supplied by three veins that reach the stigma. Ovules are anatropous, bitegmic, and crassinucellate. Lateral sepal bundles are derived either from the sepal midrib or from the petal-plane bundles; stamens are supplied by independent traces or by bundles originating from compound traces in both sepal- and petal-planes. The follicular fruits possess a sclerenchymatous endocarp and contain winged seeds that have a membranous testa, a ridged surface, and a cellular endosperm. Reproductive morphological and anatomical features are more consistent with features of the Saxifragoideae than with the Escallonioideae or the Cunoniaceae, although the essentially apocarpous gynoecium with multiovulate carpels is not found in these groups. Vegetative and reproductive characteristics indicate that Tetracarpaea is more closely related to Saxifragaceae than to Cunoniaceae. It is possible this isolated genus should have separate familial status.     

Could poor seed dispersal contribute to predation by introduced rodents in a Hawaiian dry forest?

Dry forests are among the most diverse, yet threatened, communities in Hawai’i. Dry forests throughout the archipelago suffer from a lack of natural regeneration of trees. Two factors that may limit tree recruitment include poor seed dispersal and seed predation by rodents. Poor or limited dispersal of fleshy-fruited species results in seeds and fruits falling directly under parents. Dispersed and non-dispersed seeds may differ in their vulnerability to predation. We tested effects of seed location (under/away from parent trees) and pulp (presence/absence) on predation of four native species that suffer from limited dispersal and one readily-dispersed alien species in Kanaio Natural Area Reserve, Maui. Three natives (Diospyros sandwicensis, Pleomele auwahiensis, Santalum ellipticum), had significantly more seeds removed under parent trees than in exposed sites away from trees. For the one alien (Bocconia frutescens) and two native trees (D. sandwicensis, P. auwahiensis) that were evaluated, significantly more intact fruits were removed than were cleaned seeds. Presence of teeth marks and gnawed seed husk fragments indicate introduced rodents are destroying many of the seeds they remove. These results suggest that seed predation is disproportionately concentrated among poorly-dispersed seeds and may contribute to recruitment failure.     

Beans with bugs: Covert carnivory and infested seed selection by the red-nosed cuxiú monkey

Members of the Neotropical primate genus Chiropotes eat large volumes of immature seeds. However, such items are often low in available proteins, and digestion of seeds is further inhibited by tannins. This suggests that overall plant-derived protein intake is relatively low. We examined the presence of insect larvae in partially eaten fruits, compared with intact fruit on trees, and examined fecal pellets for the presence of larvae. We found that red-nosed cuxiú (Chiropotes albinasus) individuals may supplement their limited seed-derived protein intake by ingesting seed-inhabiting insects. Comparison of fruits partially eaten for their seeds with those sampled directly from trees showed that fruits with insect-containing seeds were positively selected in 20 of the 41 C. albinasus diet items tested, suggesting that fruits with infested seeds are actively selected by foraging animals. We found no differences in accessibility to seeds, that is, no differences in husk penetrability between fruits with infested and uninfested seeds excluding the likelihood that insect-infestation results in easier access to the seeds in such fruits. Additionally, none of the C. albinasus fecal samples showed any evidence of living pupae or larvae, indicating that infesting larvae are digested. Our findings raise the possibility that these seed-predating primates might provide net benefits to the plant species they feed on, since they feed from many species of plants and their actions may reduce the populations of seed-infesting insects.     

Two new species of Ulota (Orthotrichaceae,Bryopsida) with multicellular spores,from the Hengduan Mountains,Southwestern China

Abstract

Two new species, Ulota yunnanensis and Ulota gigantospora, are described from Yunnan and Sichuan Provinces, China. Both have multicellular spores, a relatively uncommon character in the genus. Differences between the species include growth form and habit, leaf areolation, capsule shape, peristome structure and ornamentation, operculum shape and colour, as well as vaginula and calyptra hairiness. These characters and those discriminating the new species from other ones with similar spore type are discussed and illustrated.     

Spines protect plants against browsing by small climbing mammals

The presence of spines on woody plants has been shown to limit the loss of foliage to large mammalian browsers by restricting both bite size and biting rate. We tested the hypothesis that plant spines are also an effective defense against browsing by small mammals, such as rodents, that climb within the canopy of shrubs to harvest fruits, seeds, and foliage. Tame southern plains woodrats (Neotoma micropus) were allowed to harvest raisins impaled on the branches of blackbrush shrubs (Acacia rigidula Benth.) in five categories of spinescence: naturally spineless, moderately spiny, or very spiny branches, and moderately spiny and very spiny branches with the spines removed. Plant spinescence significantly reduced the woodrats foraging efficiency (P = 0.0001). Although plant spines are generally thought to be an evolved defense against browsing by ungulate herbivores, they may also reduce browsing by small mammals. Received: 15 May 1997 / Accepted: 29 August 1997