Greg K Brown

University of Wyoming | UW · Department of Botany

The performance of the deep learning-based image segmentation is highly dependent on two major factors as follows: 1) The organization and structure of the architecture used to train the model and 2) The quality of input data used to train the model. The input image quality and the variety of training samples are highly influencing the features der...

Training deep learning-based image segmentation networks require large number of samples of adequate quality. However, obtaining large number of samples is not possible in certain domains. Recent approaches use augmentation and transfer learning techniques to overcome small sample size. Augmentation techniques are known to introduce noise to the da...

Dense Residual U-Net (DRU-Net) is a neural network used for image segmentation. It is based on the U-Net architecture and isa combination of modified ResNet as the encoder and modified DenseNet as the decoder blocks. DRU-Net captures both the local and contextual information. Previous studies on DRU-Net have not tested the influence of the spectral...

Unmanned aerial vehicles (UAVs) usually capture large amounts of images. The images need not be of good quality and need not contain the data that are required. Processing and selecting valuable data from these images take time. To overcome this difficulty, deep convolutional neural network algorithms can be assigned for processing huge image data....

Unmanned aerial vehicles (UAVs) are useful for acquiring images of epiphytes as they grow on other trees and in areas that are not easily accessible. Manually identifying epiphytes in these images is both time-consuming and prone to errors. Convolutional neural networks (CNNs) are the building blocks for almost all state-of-the-art image classifica...

The deep learning (DL) models require timely updates to continue their reliability and robustness in prediction, classification, and segmentation tasks. When the deep learning models are tested with a limited test set, the model will not reveal the drawbacks. Every deep learning baseline model needs timely updates by incorporating more data, change...

Unmanned Aerial Vehicle (UAV) missions often collect large volumes of imagery data. However, not all images will have useful information, or be of sufficient quality. Manually sorting these images and selecting useful data are both time consuming and prone to interpreter bias. Deep neural network algorithms are capable of processing large image dat...

This study states all the challenges involved during flying a drone in wooded environment. This will really help in projects involves UAV in agriculture, forestry etc.

Using UAV to image target on top of tree canopies

A taxonomic revision of Bromeliaceae subfam. Tillandsioideae is presented based on a multi-locus DNA sequence phylogeny (viz., plastid DNA loci rpoB-trnC-petN, trnK-matK-trnK, and ycf1, and the nuclear DNA gene PHYC) and new or re-evaluated morphology (e.g., leaf, inflorescence, sepal, petal, ovary, stigma, stamen, pollen, ovule, and seed morpholog...

A phylogenetic study testing the monophyly of the geographically disjunct genus Ronnbergia (Bromeliaceae, Bromelioideae) is presented. The phylogenetic analyses were based on taxon sampling that included all but one species of Ronnbergia, and representative lineages across the subfamily Bromelioideae. Three chloroplast DNA sequence markers (matK, p...

Abstract— Of the eight subfamilies currently recognized in Bromeliaceae, Bromelioideae is perhaps the most poorly understood. Generic circumscriptions are unclear, and an exceptionally diverse morphology coupled with an unusually low rate of sequence divergence within Bromeliaceae has made it difficult to resolve phylogenetic relationships within t...

Background/Question/Methods Green roofs have been noted for their ability to lower energy costs, mitigate storm water runoff and reduce the urban heat island effect. However, the very nature of a green roof suggests an environment subject to intense sun exposure, limited moisture availability and desiccating winds; an environment not conducive fo...

Till. Cover photographs. Front: The spectacular Puya raimondii adorns the high mountains 6f the Peruvian and BolivianAndes. Claudia Hornung-Leoni and Victoria Sosa explore the many uses of this largest of all bromeliads. Photograph by Claudia Hornung-Leoni. Back: A blend of science and show. In this issue, Walter Till discusses the finer points of...

PREMISE: Bromeliaceae form a large, ecologically diverse family of angiosperms native to the New World. We use a bromeliad phylogeny based on eight plastid regions to analyze relationships within the family, test a new, eight-subfamily classification, infer the chronology of bromeliad evolution and invasion of different regions, and provide the bas...

From 1990 to 2006, 2,875 new angiosperm species were described in Brazil, including 280 newBromeliaceae species. This publication rate is considered to be a useful indicator of floristic richness andalso reveals the huge gaps in our knowledge of species that make up Brazilian biomes and the importanceof taxonomy as a basic tool to assess biodiversi...

Considerable taxonomic confusion exists among species of Aechmea subgenus Macrochordion (Bromeliaceae), which comprises the A. bromeliifolia complex. Cluster and principal components analyses were performed in order to identify how many taxa exist in this complex and how they can be distinguished morphologically. Data for 16 morphological character...

A cladistic analysis of Lymania was conducted using morphology and sequences from three chloroplast DNA regions: the matK coding region and the psbA-trnH and trnL-trnF intergenic spacers. The monophyly of the genus and the phylogenetic relationships among related genera were examined. Of the nine Lymania species, eight are endemic to southern Bahia...

A cladistic analysis of morphological data for the genus Canistropsis is presented. With the exception of two species, C. selloana and C. correia-araujoi, results support Canistropsis as monophyletic. Canistropsis correia-araujoi is a suspected, natural bigeneric hybrid. Canistropsis selloana is transferred back into the monotypic genus Andrea. A t...

Seed morphology has been an important taxonomic character for the Bromeliaceae, with three distinct seed types, naked, winged, and plumose, corresponding to the traditionally recognized subfamilies, Bromelioideae, Pitcairnioideae, and Tillandsioideae, respectively. In Tillandsioideae, the type of plumose seed appendage is used, in conjunction with...

Members of Catopsis were examined for taxonomically useful morphological and anatomical characteristics related to leaves. External features included rosette shape, leaf size and shape, presence of epicuticular wax, abundance and character of trichomes, and ratio of trichomes to stomata. Leaf anatomical characters included arrangement of stomatal-c...

Aechmea (ca. 220 species) is the largest and most diverse genus in Bromelioideae (Bromeliaceae), and several dissimilar generic concepts and infrageneric classifications have been proposed, frequently involving other closely related Bromelioideae. A morphology-based phylogenetic analysis using parsimony was conducted with 86 taxa, including 52 Aech...

We investigated genetic variation within and between 3 populations of Gaura neomexicana ssp. coloradensis, a federally listed threatened species, using inter-simple sequence repeats. The data matrix included 24 individuals scored for 88 bands, with 3.4% missing data. Cluster analysis showed that members of the 3 populations are very similar and are...

The Bromeliaceae is characterized by a 2n chromosome number of 50, but exceptions have been reported. These include scattered polyploids and presumed aneuploid reductions in isolated species from subfamilies Tillandsioideae and Bromelioideae, and 2n = 34 or 36 for all species of Cryptanthus (Bromelioideae) thus far examined. Two hypotheses have bee...

Parsimony analysis of 31 sequences of the chloroplast locus ndhF was used to address questions of subfamilial phylogeny in Bromeliaceae. Results presented here are congruent with those from chloroplast DNA restriction site analysis in recognizing a clade containing Bromelioideae and Pitcairnioideae, and in resolving Tillandsioideae near the base of...

Nucleotide sequences of the plastid locus ndhF are used to examine phylogenetic relationships among 25 representative species of subfamily Tillandsioideae. Genetic divergence among bromeliad taxa is low for ndhF sequences, ranging from 2.1% between Catopsis wangerinii and Tillandsia tricholepis, to 0.2% between several species of Guzmania, Mezobrom...

The Bromeliaceae were surveyed for petal appendage morphology using light and scanning electron microscopy. Three general morphological types were recognized, each loosely correlating with one of the three subfamilies. Petal appendage elaboration and variation were greatest in the Bromelioideae, while subfamilies Pitcairnioideae and Tillandsioideae...

The Bromeliaceae were surveyed for petal appendage morphology using light and scanning electron microscopy. Three general morphological types were recognized, each loosely correlating with one of the three subfamilies. Petal appendage elaboration and variation were greatest in the Bromelioideae, while subfamilies Pitcaimioideae and Tillandsioideae...

Plication of stamina!filaments is an important diagnostic character for Tillandsia subgenus Anoplophytum (ca. 45 species). The monophyletic integrity of subgenus Anoplophytum has recently been questioned, and we conducted an anatomical investigation of plicate stamina! filaments to better characterize this putative synapomorphy. Developmental studi...

Plication of staminal filaments is an important diagnostic character for Tillandsia subgenus Anoplophytum (ca. 45 species). The monophyletic integrity of subgenus Anoplophytum has recently been questioned, and we conducted an anatomical investigation of plicate staminal filaments to better characterize this putative synapomorphy. Developmental stud...

The genus Glomeropitcairnia has long been poorly understood. It has been placed variously within the bromeliad subfamily Tillandsioideae along with five other recognized tillandsioid genera (Catopsis, Guzmania, Mezobromelia, Tillandsia, and Vriesea); in its own tribe of the tillandsioid subfamily; and, alternatively, has been considered to be a sub...

Eighty-three chromosome counts are reported for 72 taxa of the Bromeliaceae. Fifty-eight of these counts are the first known chromosome number reports for their respective taxa. A model of chromosomal evolution in the Bromeliaceae (n = 25) is presented. The model is parsimonious and consistent with existing data on meiotic chromosome numbers within...

Over 400 taxa in the Bromeliaceae were surveyed for stigma morphology. Five morphological categories (conduplicate-spiral, simple-erect, cupulate, convolute-blade, and coralliform) account for all known variation in bromeliad stigma morphology. The coralliform type is described and illustrated for the first time. The subfamilies Bromelioideae and P...

Scanning electron and light microscopy observations of wet-preserved flowers of Bromeliaceae subfamily Pitcaimioideae yield new information on the stigma, petal scales, and septal nectaries. Variations of the stigma types are evident among several genera. The gross structural features of the stigma do not indicate definite pollination trends, but t...

Cladistics, phenetics, and our understanding of chromosomal evolution were applied to questions of the relationships and resemblances among the three subfamilies of the monocot family Bromeliaceae. This large, distinct family (2100 species) is mostly from the new world tropics. Among 10 possibly closely related families to the monotypic order Brome...

Tillandsia L. Subg. Phytarrhiza (Visiani) Baker (Bromeliaceae) is a distinctive group of about 35 epiphytic species. These exhibit a range of habits from xeric to mesic. The evolutionary relationships of the contrasting adaptations need to be established here as well as in the subfamily as a whole. Relations between the subgenus and other tillandsi...

Tillandsia L. Subg. Phytarrhiza (Visiani) Baker (Bromeliaceae) is a distinctive group of about 35 epiphytic species. These exhibit a range of habits from xeric to mesic. The evolutionary relationships of the contrasting adaptations need to be established here as well as in the subfamily as a whole. Relations between the subgenus and other tillandsi...

An international cooperative project involving more than 16 resident botanists in tropical America was initiated in 1984 to attempt to resolve distributional, phylogenetic and classification problems in Bromeliaceae. The research project serves as a template for studies in other groups of organisms with tropical American distributions.

Lomatium tuberosum Hoover, a south-central Washington endemic, has been considered to be closely related to three other normally purple-flowered lomatiums:L. columbianum, L. cuspidatum, andL. minus. Recent morphologic studies confirm the close phenetic relationship of these four species. Chromosome counts from a purple-flowered population in the ea...

Lack of agreement has characterized delimitation of Phytolaccaceae s.l. over the past several decades. The inclusion or exclusion of Achatocarpus and Phaulothamnus, Agdestis, Stegnosperma, and Barbeuia, often referred to as anomalous genera in Phytolaccaceae s.l., has been the reason for disagreement in the classification of Phytolaccaceae. Chromos...

Three distinct types of stigma architecture, designated as “simple-erect,” “conduplicate-spiral”, and “convolute-blade” were identified for Bromeliaceae. Structure of the conduplicate-spiral and convolute-blade stigma types is highly complex and previously unreported. Stigma morphology, largely neglected in Tillandsioideae until recently, promises...

Diploid (2n = 12II), tetraploid, pentaploid, and hexaploid level chromosome numbers are reported for Platyschkuhria Rydb. (Compositae). First reports of accessory chromosomes in the genus are also presented. Known polyploidy in Platyschkuhria is thus far restricted to P. integrifolia (Gray) Rydb. var. desertorum (M. E. Jones) Ellison from south-cen...

Haplopappus sect. Gymnocoma consists of six taxa, H. humilis, H. integerrimus var. integerrimus, H. integerrimus var. punctatus comb. nov., H. pedunculosus, H. pinnatifidus, and H. schumannii comb. nov., all restricted to central Chile. Diagnostic features for sect. Gymnocoma include congested, linear to narrowly oblanceolate, pointed leaves that b...

Thirteen flavonoids and the coumarin esculetin were isolated from Haplopappus scrobiculatus, and five of the flavonoids were also found in H. sericeus. Both species yielded quercetin, quercetin 3-β-D-glucoside, isovitexin, vitexin, and vicenin-2 (6,8-di-C-glucosylapigenin). In addition, H. scrobiculatus was found to accumulate isorhamnetin, isorham...

Nine flavonoids including two new myricetin derivatives, myricetin 3′,4′-dimethyl ether and myricetin 3,3′, 4′-trimethyl ether, were obtained from Haplopappus integerrimus var. punctatus. The known compounds are quercetin 7,3′-dimethyl ether, querectin 3,3′-dimethyl ether, isorhamnetin, quercetin 3,7-dimethyl ether, quercetin 3-methyl ether, querce...

Chromosome counts are reported for 33 species from all four sections of the genus Haplopappus in South America. These include first reports for 28 species and two putative hybrids. All chromosome numbers reported herein are 2n = 5II, with the exception of H. prunelloides with 2n = 6II. Unlike the North American species, the morphological diversity...

Eight flavonoids, including the new scutellarein 6-β-D-glucoside, were isolated from the leaves of Haplopappus rengifoanus Remy in Gay (Compositae). The known compounds are apigenin, luteolin, quercetagetin 3-methyl ether, quercetagetin 3,7-dimethyl ether, isorhamnetin and its 3-β-D-galactoside, and 3-β-D-glucoside.

Flavonoids were identified by PC and HPLC from the flowers of three cholla species and their known diploid and triploid hybrids. All the individuals examined produce quercetin 3-glucoside, quercetin 3-rutinoside and kaempferol 3-glucoside, which vary quantitatively among taxa.

Pollen grains of Haplopappus and related genera in the subtribe Solidaginae from North and South America were examined by light and scanning electron microscopy. The grains are consistently tricolporate and echinate. Some genera can be distinguished by pollen size, spine length, and number of spine rows between colpi. Based on these characters, the...