EVIDENCE FOR INHIBITORS OF SPORANGIUM FORMATION IN LAMINARIA DIGITATA (PHAEOPHYCEAE) DURING THE SEASON OF RAPID GROWTH

The pathway from the intercalary frond meristem to distal frond portions was blocked in experimental sporophytes of Laminaria digitata (Huds.) Lamour. in January by cutting 2 or 3 holes (15–25 mm diameter) 5 cm from the base of the frond. This procedure resulted in the formation of sori adjacent to the distal edge of the holes within 5–10 weeks. Frond portions that were cut at least 20 cm away from the stipe–frond transition readily formed sori within 5–7 weeks after isolation from the rest of the thallus. These findings suggest that the basal actively dividing and expanding part of the laminarian frond is the source of inhibitors of sporangium formation that move in a distal direction and keep the young frond free of sori during the season of rapid growth (i.e. during the first part of the year). The natural occurrence of sori during the season of slow growth (i.e. the second part of the year in the Northern Hemisphere) may be due to reduced synthesis and export of inhibitors of sporangium formation from the more or less resting basal meristem.     

MITOSIS IN SUSPENSION CULTURES OF HIGHER PLANT CELLS IN A SYNTHETIC MEDIUM

Torrey , J. G., J. Reinert , and N. Merkel . (Harvard U., Cambridge, Mass.) Mitosis in suspension cultures of higher plant cells in a synthetic medium. Amer. Jour. Bot. 49(4): 420–425. Illus. 1962.—A cytological study was made of plant tissue cultures growing in liquid synthetic medium. Mitoses in cell suspension cultures of root callus tissues of Daucus carota L., Convolvulus arvensis L. and Haplopappus gracilis (Nutt.) Gray were found to occur frequently in the first 2 weeks of culture with the highest frequency at about 7 days. No mitoses were observed after 3 weeks, although fresh weight and the number of free-floating cells in the suspension continued to increase for the entire culture period of 4–6 weeks. Mitoses were most frequent in tissue pieces, but occasional mitoses in single isolated cells in suspension were observed in each type of tissue. Normal mitoses were observed in diploid and polyploid cells of all 3 types of tissues cultures. Little evidence of nuclear or chromosomal aberrations was observed in these cultures.     

SCANNING ELECTRON MICROSCOPY OF THE UREDINIAL STAGE OF PUCCINIA CANALICULATA ON YELLOW NUTSEDGE,CYPERUS ESCULENTUS (CYPERACEAE)

The ultrastructure of the uredinial stage of the rust fungus, Puccinia canaliculata (Schw.) Lagerh., on yellow nutsedge (Cyperus esculentus L.) is described using scanning electron microscopy. This rust has been proposed as a potential biological control agent against this serious weed species. Urediniospores are ellipsoid to ovoid, and echinulate with the spines distributed over the surface except at basal portions. Spines are in circular depressions, encircled by annuli. Germination is through one of two equatorial germ pores. Germ tube growth is primarily perpendicular to the longitudinal orientation of epidermal cells. Appressoria completely cover stomata. Uredinia develop within linearly aligned intercellular cavities in substomatal regions. Uredinia become erumpent, exposing pedicellate urediniospores and smooth paraphyses scattered throughout the sori. Uredinia are nonperidiate.     

Reproductive parameters of rhinobatid and urolophid batoids taken as by‐catch in the Queensland (Australia) east coast otter‐trawl fishery

Reproductive variables are provided for batoids regularly taken as by‐catch in the east coast otter‐trawl fishery on the inner‐mid continental shelf off the south‐east and central coasts of Queensland, Australia. Total length at maturity (L_T50 and 95% c.i .) for the eastern shovelnose ray Aptychotrema rostrata was 639·5 mm (617·6–663·4 mm) for females and 597·3 mm (551·4–648·6 mm) for males. Litter size (n = 9) ranged from nine to 20 (mean ± s.e. = 15·1 ± 1·2). This species exhibited a positive litter size–maternal size relationship. Disc width at maturity (W_D50 and 95% c.i .) for the common stingaree Trygonoptera testacea was 162·7 mm (155·8–168·5 mm) for females and 145·9 mm (140·2–150·2 mm) for males. Gravid T. testacea (n = 6) each carried a single egg in the one functional (left) uterus. Disc width at maturity (W_D50 and 95% c.i .) for the Kapala stingaree Urolophus kapalensis was 153·7 mm (145·1–160·4 mm) for females and 155·2 mm (149·1–159·1 mm) for males. Gravid U. kapalensis (n = 16) each carried a single egg or embryo in the one functional (left) uterus. A single female yellowback stingaree Urolophus sufflavus carried an embryo in each uterus. A global review of the litter sizes of shovelnose rays (Rhinobatidae) and stingarees (Urolophidae) is provided.     

EFFECTS OF ICE ON ASCOPHYLLUM NODOSUM WITHIN THE GREAT BAY ESTUARY SYSTEM OF NEW HAMPSHIRE-MAINE12

The, effects of ice on Ascophyllum nodosum (L.) Le Jolis within the Great Bay Estuary System of New Hampshire-Maine, U.S.A. were assessed during the winter of 1980–81. Approximately 50% of the plants late fall standing crop, or an estimated 136 tonnes dry weight, was removed by ice-rafting. Pieces of Ascophyllum removed averaged 22 cm in length, 15 g in fresh weight and generally represented 2–3 years of growth. Although the winter of 1980–81 wax somewhat extreme, a similar pruning process probably occurs each year contributing to the characteristic bushy habit of attached inner estuarine plants. Ascophyllum fragments rafted in ice and deposited into salt marshes are suggested as a major source of the, ecad scorpioides (Hornemann) Hauck.     

MORPHOLOGY AND DEVELOPMENT OF AHNFELTIA PLICATA (RHODOPHYTA): PROPOSAL OF AHNFELTIALES ORD. NOV.1

Ahnfeltia plicata (Hudson) Fries, the type species of Ahnfeltia Fries, is currently assigned to the Phyllophoraceae (Gigartinales). Several morphological and biochemical characters distance A. plicata from the Phyllophoraceae but, because sexual reproduction has never been demonstrated, an alternative placement has not been possible. A. plicata now is shown to have a heteromorphic sexual life history. Erect branched gametophytes are dioecious. In male sori, spermatangia are cut off transversely from spermatangial mother cells. Female sori form numerous terminal sessile carpogonia. Following fertilization, several zygotes in each sorus fuse facultatively with undifferentiated intercalary cells of the female sorus and cut off gonimoblast initials obliquely outwards. These initials give rise to branching gonimoblast filaments that fuse with apical and intercalary female sorus cells and with each other, then grow radially outward in the compound external carposporophyte and terminate in carposporangia. Carpospores develop in culture into crustose tetrasporophytes identical to Porphyrodiscus simulans Batters. Field-collected P. simulans tetraspores grew into erect A. plicata axes. Tetrasporangia are formed by division and enlargement of crust apical cells followed by sequential enlargement and maturation of tetrasporocytes in an erosive process. Monosporangia are formed in sori on male gametophytes. Pit plugs of both gametophyte and tetrasporophyte phases consist of naked plug cores without cap layers of membranes. Gametophytes exhibit both cell fusions and secondary pit connections whereas tetrasporophytes form cell fusions but lack secondary pit connections. On the basis of the unique female and postfertilization reproductive development and in conjunction with the pit plug structure which is unique among florideophytes, the order Ahnfeltiales, containing the family Ahnfeltiaceae, is proposed.     

GROWTH RESPONSES FROM WHOLE FRUIT AND FRUIT HALVES OF LEMON CULTURED IN VITRO

A comparative growth study was conducted on juice vesicles cultured in the form of various fruit explant types (equatorially bissected fruit halves, longitudinally bissected fruit halves, one-eighth sections of fruit, one-quarter sections of fruit, whole carpel segments, 2 or 3 mm thick equatorial slices of fruit, and 1 cm² fruit endocarp pieces) from 15 mm diam Citrus limon (L.) Burm. f. cv. Eureka lemons. Juice vesicles within equatorial fruit halves produced the least amount of callus. Furthermore, these juice vesicles grew similarly to juice vesicles occurring in the tree grown fruit. A study of cultured equatorial fruit halves using 10–45 mm diam lemons was then conducted. Fruit half cultures containing juice vesicles could be readily established from 15–45 mm diam lemons. Vesicles from 10 mm diam fruit halves, however, invariably produced callus. Vesicles cultured within fruit halves produced proportionately less callus as their fruit diam increased. Juice vesicles cultured in 15–30 mm diam fruits lost their original green color and turned opaque as they matured (i.e., after 3–6 months in culture). A method is also presented, whereby whole lemon fruits can be established and maintained in vitro. Lemons, 35–45 mm in diam, were the best explant sources for establishing whole fruit cultures. Juice vesicles in whole fruit cultures may remain viable for up to 8 months in culture.     

Phenology of Dryopteris affinis ssp. affinis and Polystichum aculeatum: modeling relationships to the climatic variables in a Mediterranean area

The phenology of leaves and stages from immature sori to spore release were studied in natural populations of two perennial herbaceous ferns, Dryopteris affinis ssp. affinis and Polystichum aculeatum, for 2 years in Italy. The Generalized Additive Model for Location, Scale and Shape (GAMLSS) was used to predict a particular phenological event from the climatic variables. Both fern species are evergreen with leaf lifespan of 13–14 months in D. affinis ssp. affinis and 15–24 months in P. aculeatum. Their leaf production is seasonal with most flushed in spring. In D. affinis ssp. affinis the decaying of old leaves is sudden whereas in P. aculeatum it is gradual, and in both types the decaying is accelerated just as the new leaves emerge. Temperature is the best predictor for the development of sori and spore release. The end of spore release and leaf emergence are positively affected by temperature and negatively affected by rainfall and snow cover for P. aculeatum. An almost similar response to climatic factors of emergent and senescent leaves and their phenology supportsthe hypothesis that old leaves serve as nutrient storage organs for new leaf growth. Comparison the phenological patterns between the 2 years indicated that the time lapses between each phenological event were the same within seasons for D. affinis ssp. affinis but show some differences for P. aculeatum. We also hypothesize that endogenous factors may play an important role in the phenology of P. aculeatum.     

The epidemiology of tomato brown root rot

In the absence of nematodes, three different symptoms of disease, parts of the brown root rot complex (BRR), occurred on tomato roots surviving in soils infested with GSF (= grey sterile fungus) and Colletotrichum atramentarium (Berk. & Br.) Taubenh. In heavily infested soils brown lesions occurred throughout cropping, appearing within a week of planting. Corkiness and black dot, caused by GSF and C. atramentarium respectively, rarely occurred until the third month after planting but towards the end of the season the incidence of black dot sometimes suddenly increased greatly. Observations of crops growing in plots treated with different soil partial sterilants suggested that GSF was more damaging than C. atramentarium. Yield was not related to the incidence of black dot but was inversely proportional to the occurrences of brown lesions and corkiness. The relation with brown lesions was significant within 8 weeks of planting, when most brown lesions gave cultures of GSF, but later more of these lesions gave cultures of C. atramentarium than of GSF. Pathogenicity tests with pure cultures of GSF and C. atramentarium were done on agar media and by artificially infesting partially sterilized soils. Roots of undamaged seedlings on agar media developed 10 mm. brown lesions within 2 weeks of inoculating 10-day-old tomatoes with most GSF cultures isolated from: (1) rotted roots of Lycopersicon esculentum, Solanum capsicastrum, Capsicum annuum var. longum and C. frutescens; (2) browned zones of Lycopersicon hirsutum roots; and (3) apparently healthy roots of Cucumis sativus. After inoculation with C. atramentarium, small (c. 2 mm.) pink lesions developed, whereas none formed using Pyrenochaeta spp. In soil tests the greater root damage done by GSF, including root loss, was reflected in decreased aerial growth and smaller fruit yields; C. atramentarium affected neither. In the second year of soil infestation GSF decreased yields during 6 weeks of picking from 1.96 kg. in the uninoculated controls to 1.02 kg./plant. The pattern of damage done by GSF changed as plants aged. In soil, brown lesions occurred within a few days of planting but corkiness did not appear for 2–3 months, when stem lesions and leaf yellowing often developed simultaneously. A 50% root loss after 21 weeks did not affect fruit yields whereas a 40% loss within 11 weeks of planting was reflected by a 45% yield decrease.     

Reproductive structures of Dictyopteris undulata (Dictyotales, Phaeophyceae) from Japan

sporophytes, and both male and female gametophytes of Dictyopteris undulata Holmes were collected from the Pacific coast and the Japan Sea coast of Japan. Female gametophytes are reported for the first time in the present study. All reproductive structures are aggregated in sori that form on both sides of the midrib in the upper and the middle parts of a blade. Tetraspor-angia are spherical and project from the cortical layer with a 2–4-celled stalk at the base. They are sometimes divided tetrahedrally to form four spores, but often remain undivided. Oogoniat sori also project from the cortical layer. Each oogonium is ovoid, sometimes borne on a single stalk cell at the base. Antheridial sori appear swollen above the cortex and each antheridium has a basal stalk cell. Fertile female gametophytes and te-trasporophytes are difficult to distinguish from each other in surface view because tetrasporangial and oogonial sori are similar in size and undivided tetrasporangia resemble oogonia. Oogonia are not so closely packed in small groups, unlike in Dictyota species, and they can be distinguished by the cell sizes (i.e. tetrasporangia are bigger in diameter than oogonia).     

Injection–Infiltration of Attached Grapefruit with Xanthomonas citri subsp. citri to Evaluate Seasonal Population Dynamics in Citrus Canker Lesions

To study population dynamics of Xanthomonas citri subsp. citri (Xcc) in citrus canker lesions on fruit, a needle‐free injector was used for infiltration of bacterial inoculum into fruit in situ on mature ‘Ruby Red’ grapefruit (Citrus paradisi Macf.) trees in Florida. Inoculations of Xcc at 10⁵ colony‐forming units (cfu) per ml were conducted in 2012 and 2013 on attached fruit varying from 15 mm to 90 mm in diameter. Inoculations were repeated every 2–3 weeks until the fruit were no longer injectable. On fruit less than 40 mm in size, erumpent lesions formed within 2 weeks of inoculation and expanded 1–9 mm in diameter from 30 to 120 days postinoculation (dpi). Xcc populations in lesions were 6–8 log cfu per lesion at 30 dpi and maintained this population up to 90 dpi. By 120 dpi, Xcc populations declined 1–3 log units as rainfall and temperature decreased in September–October. Xcc populations declined to ~3 log cfu per lesion after 120 dpi in November 2012 and 2013, whereas the population resurged to 5 log cfu per lesion after 180 dpi in January–February 2014.     

A NEW SPECIES OF DICTYOSTELIUM FROM HAWAII

A new species of Dictyostelium, isolated from a decaying ear of corn in Hawaii, is described. Because of the numerous irregularities in its developmental morphology and general appearance, it is being named D. irregularis. Aggregation is by amoebal streaming, and the aggregation mass commonly segments into several pseudoplasmodia, each of which produces a sorocarp in situ or after migration. During migration stalk material is laid down behind the pseudoplasmodium. The mature sorocarps, which do not exceed 1 mm in height, have very irregular stalks and globular-to-elongate sori with elliptical spores that measure 3.5-7 × 4.8-9.8μ. Cyst formation was not observed. The new species is of particular interest from the standpoint of its probable primitive position in the genus.     

New record of Sporochnus dotyi (Sporochnales,Phaeophyceae) from Kii Peninsula,Japan

The subtidal brown algal species Sporochnus dotyi Brostoff (Sporochnales, Phaeophyceae), which has been regarded as a Hawaiian endemic, is reported from Kushimoto, Kii Peninsula, Pacific coast of central Honshu, Japan, for the first time outside Hawai'i. The species grew on subtidal rocks ca. 5–20 m deep attached by a small conical holdfast. The erect thalli were 5–30 cm high, terete, robust and alternately branched in 1–2 orders. When mature, pedicellate receptacles developed on the branches, and formed elliptical sori 1 mm long with a pedicel 3–5 mm long. The apical parts of the thalli and the receptacles were terminated with a tuft of simple assimilatory filaments of up to 4 mm long and showed prominent green to yellow underwater iridescence. Reproductive filaments (paraphyses) were densely packed, simple, up to 200 μm long and bore 4–6 mostly unilateral unilocular zoidangia 20–22 μm long and 5–6 m in diameter. In the genetic analyses, the Sporochnus alga from Kushimoto had partial rbcL sequence identical to S. dotyi from Hawai'i. The cox3 phylogeny revealed that this alga formed a fully supported clade with S. dotyi. Therefore, we identified the alga from Kushimoto as S. dotyi. This finding of S. dotyi from Japan, together with the recent reports of the mesophotic macroalgae Ryuguphycus kuaweuweu (=Umbraulva kuaweuweu), Ulva iliohaha and Newhousia imbricata from various localities in the Pacific Ocean including Japan, suggest closer biogeographical connections of subtidal/mesophotic macroalgae in the Pacific than previously recognized.     

An in vitro method for establishing mycorrhizae on coniferous tree seedlings

Summary A method for in vitro synthesis of mycorrhizae on coniferous tree seedlings is described. Tree seedlings (Larix decidua Mill., Picea abies (L.) Karst, and Pinus sylvestris L.) and fungi Amanita muscaria (L. ex Fr.) Hooker, Piloderma croceum Erikss. et Hjorst., Pisolithus tinctorius (Pers.) Coker et Couch, and Suillus grevillei (Klotzsch) Singer were maintained under sterile conditions in petri dishes. Typical ectomycorrhizae were established within 2–3 weeks after inoculation and within 2 months after germination of seedlings. Eventually a high percentage of mycorrhizal root tips was obtained.     

MICROENVIRONMENTS AND MICROSCALE PRODUCTIVITY OF CYANOBACTERIAL DESERT CRUSTS1

We used microsensors to characterize physicochemical microenvironments and photosynthesis occurring immediately after water saturation in two desert soil crusts from southeastern Utah, which were formed by the cyanobacteria Microcoleus vaginatus Gomont, Nostoc spp., and Scytonema sp. The light fields within the crusts presented steep vertical gradients in magnitude and spectral composition. Near-surface light-trapping zones were formed due to the scattering nature of the sand particles, but strong light attenuation resulted in euphotic zones only ca. 1 mm deep, which were progressively enriched in longer wavelengths with depth. Rates of gross photosynthesis (3.4–9.4 mmol O₂·m^?2·h^?1) and dark respiration (0.81–3.1 mmol O^?2·m^?2·h^?1) occurring within 1 to several mm from the surface were high enough to drive the formation of marked oxygen microenvironments that ranged from oxygen supersaturation to anoxia. The photosynthetic activity also resulted in localized pH values in excess of 10, 2–3 units above the soil pH. Differences in metabolic parameters and community structure between two types of crusts were consistent with a successional pattern, which could be partially explained on the basis of the microenvironments. We discuss the significance of high metabolic rates and the formation of microenvironments for the ecology of desert crusts, as well as the advantages and limitations of microsensor-based methods for crust investigation.     

Isolation of 4-Hydroxy-5-methyl-3(2H)-furanone,a Flavor Component in Shoyu (Soy Sauce)

An analytical method was developed for determining the four optical isomers of a new synthetic pyrethroidal insecticide, α-cyano-3-phenoxy-benzyl 2-(4-chlorophenyl)isovalerate (Fenvalerate, S–5602). The cyano group in S–5602 molecule was converted into l-menthyloxycarbonyl group by heating S–5602 with l-menthol and hydrochloric acid. The obtained diastereoisomer derivative (l-menthyl ester deriv.) was chromatographed on a μPorasil column (4 mm i.d. × 0.3 m) using a solvent system of hexane-ethyl acetate (500+7, v/v) as a mobile phase, and the four isomers of S–5602 were separated from one another within 20 min. The compositions of S–5602 isomers were determined from their peak areas.     

Planulation,larval biology,and early growth of the deep‐sea soft corals Gersemia fruticosa and Duva florida (Octocorallia: Alcyonacea)

Abstract. Although the reproductive biology and early life‐history stages of deep‐sea corals are poorly understood, such data are crucial for their conservation and management. Here, we describe the timing of larval release, planula behavior, metamorphosis, settlement, and early juvenile growth of two species of deep‐sea soft corals from the northwest Atlantic. Live colonies of Gersemia fruticosa maintained under flow‐through laboratory conditions released 79 planulae (1.5–2.5 mm long) between April and early June 2007. Peak planulation in G. fruticosa coincided with peaks in the chlorophyll concentration and deposition rates of planktic matter. Metamorphosis and settlement occurred 3–70 d post‐release. The eight primary mesenteries typically appeared within 24 h, and primary polyps grew to a height of ～6–10 mm and a stalk diameter of ～1 mm within 2–3 months. Planulae of Duva florida (1.5–2.5 mm long) were extracted surgically from several colonies and were successfully reared in culture. Primary polyps reached a height of ～3–4 mm within 2–3 months. No budding of primary polyps was observed in either species over 11–13 months of monitoring, suggesting a very slow growth rate.     

SPOROGENESIS UNDER ULTRAVIOLET RADIATION IN LAMINARIA DIGITATA (PHAEOPHYCEAE) REVEALS PROTECTION OF PHOTOSENSITIVE MEIOSPORES WITHIN SORAL TISSUE: PHYSIOLOGICAL AND ANATOMICAL EVIDENCE1

To study the effect of different radiation conditions on sporogenesis of Laminaria digitata (Huds.) J. V. Lamour., excised disks were induced to form sporangia under PAR (P), PAR + ultraviolet‐A (UVA) (PA), and PAR + UVA + ultraviolet‐B (UVB) (PAB) conditions in the laboratory. Vitality of meiospores, released from sori induced under different radiation conditions in the laboratory and from sori of wild sporophytes acclimated to in situ solar radiation in the presence and absence of ultraviolet radiation (UVR), was measured in terms of their germination capacity. Sorus induction in disks of laboratory‐grown sporophytes was not hampered under light supplemented with UVR, and sorus area was not significantly different among P, PA, and PAB. Vitality and germination rate of meiospores released from sori induced under different radiation treatments was comparable. Likewise, screening of UVR of the natural solar radiation did not promote higher germination rates of meiospores released from wild sporophytes. Germination rates were, however, higher in meiospores released from laboratory‐induced sori compared to sori of wild sporophytes. Higher DNA damage (formation of cyclobutane pyrimidine dimers, CPDs) was observed in laboratory‐grown nonsorus compared to sorus tissue, while CPDs were nondetectable in both sorus and nonsorus tissue of wild sporophytes. To explain the apparent protection of developing meiospores and the unexpected UV resistance of soral tissue, concurrent anatomical investigations of sporogenic tissue were performed. We observed the previously unreported existence of two types of sterile paraphysis cells. One type of paraphysis cells, the most frequent type, contained several red‐fluorescing plastids. The other type, less frequently occurring, was completely filled with substances emitting blue fluorescence under violet excitation, presumably brown algal phenolic compounds (phlorotannins). Cells of this type were irregularly scattered within the sorus and did not contain red‐fluorescing plastids. Meiospore‐containing sporangia were positioned embedded between both types of paraphysis cells. In vegetative tissue, blue autofluorescence was observed only in injured parts of the blade. Results of our study suggest that the sorus structure with phlorotannins localized in the specialized paraphysis cells may be able to screen harmful UVR and protect UV‐sensitive meiospores inside the sporangia.     

NATURE OF THE PLANT COMMUNITY. V. VARIATION WITHIN THE TRUE PRAIRIE COMMUNITY-TYPE

Mc Millan , C. (U. Texas, Austin.) Nature of the plant community. V. Variation within the true prairie community-type. Amer. Jour. Bot. 46(6): 418–424. Illus. 1959.—Population samples of grass species were transplanted to Lincoln, Nebraska, from two grassland communities within the general distribution of the true prairie community-type. These represented extensive grassland areas near Watertown, South Dakota, and Manhattan, Kansas. True prairie relicts near Colorado Springs, Colorado and in the Black Hills of southwestern South Dakota were also studied in the transplant garden. Only in one species, Stipa spartea Trin., were the transplanted populations essentially similar in behavior. In 8 of the species, Koeleria cristata (L.) Pers., Bouteloua gracilis (H.B.K.) Lag., B. curtipendula (Michx.) Torr., Schizachyrium scoparium Nash, Andropogon gerardi Vitman, Panicum virgatum L., Sorghastrum nutans (L.) Nash, and Sporobolus heterolepis (A. Gray) A. Gray, the Manhattan populations were the latest flowering. In Elymus canadensis L., the Manhattan population was the earliest flowering. The abstraction of two communities into a true prairie type of community with other communities of similar species-populations is a convenient method for discussing distributional phenomena. However, extreme caution must be used in generalizing about characteristics other than distributional. If the 10 species in the present study were designated by letters, the Watertown and Manhattan communities could be compared ecologically as a b' c d e f g h i j and a b c' d' e' f' g' h' i' j'. The use of taxonomic relationship in vegetational studies is convenient for the reduction of sample size, but the vital aspect of studying variation within the species is in the determination of harmony between vegetation and its habitat. The relict communities are in adjustment with their habitats and represent the results of natural selection in favoring early-flowering variants within a number of different species. The key to distribution of the true prairie vegetation, widespread or relict, lies in the harmony between a habitat variable and a vegetation variable. Through natural selection, each stand of true prairie may be fundamentally different from any other stand.     

Stromanthe bahiensis sp. nov. (Marantaceae), endemic to southern Bahia State,Brazil

Stromanthe bahiensis Yoshida‐Arns, Mayo & J. M. A. Braga sp. nov. (Marantaceae) is described as an endemic to the Atlantic Forest coast of southern Bahia State in Brazil. It is similar to S. hjalmarssonii (Körn.) Petersen, which is restricted to Central America, but differs from it by the following characteristics: petiole 14–70 cm long, leaf blade oblong‐ovate to ovate‐lanceolate, fertile bracts 18–30×2–4 mm, narrowly lanceolate to ovate‐lanceolate, sepals 4–6 mm long, corolla lobes 3.0–3.5 mm long, outer staminodes 2.0–3.5×1–2 mm, pale bluish or purplish, callose staminode 2–3×1–2 mm, cucullate staminode 2–3 mm long and ovary hirsute. The new species is described and illustrated with diagnostic characters, taxonomic comments and remarks on its conservation status.