CHROMOSOME NUMBERS OF SOME EAST AFRICAN GRASSES

Chromosome numbers of 133 collections of grasses belonging to 51 genera and 105 species are reported here for material from East Africa. These include first counts for 5 genera and 51 species. The basic chromsome number of x = 6 has been found in Sporobolus; x = 10 in Loudetia and x = 13 in Pentaschistis have been confirmed. It is pointed out that chromosomes of Eragrostis vary considerably in size. The genera Harpachne, Commelinidium, Acritochaete, Pseudechinolaena and Exotheca, which are cytologically examined for the first time, have chromosomes with the socalled “panicoid” features, viz., chromosomes with small size and x = 9 or 10.     

CHROMOSOME NUMBERS OF TROPICAL AMERICAN GRASSES

Chromosome counts are reported for 81 collections of tropical grasses from Suriname, Brazil and the Dominican Republic, these representing 29 genera and 65 species. The records for Bulbulus, Guadua, Homolepis and Piresia are the first for these genera, as are the counts for the 36 following species: Arundinella confinis, Axonopus marginaius, Axonopus sp. nov., Bulbulus nervatus, Digitaria fuscescens, D. neesiana, Echinolaena inflexa, Elyonurus adustus, Eragrostis glomerata, E. maypurensis, E. polytricha, Guadua capitata, Homolepis isocalycia, Ichnanthus nemoralis, I. pollens, I. panicoides, I. proeurrens, I. reclivis, Lasiacis ligulata, Manisuris loricata, Mesosetum loliiforme, Olyra cordifolia, O. micrantha, O. obliquifolia, O. taquara, Panicum echinulatum, P. trachystachyum, P. versicolor, Paspalum dispar, P. erianthum, P. melanospermum, P. peclinatum, P. rupestre, Piresia goeldii, Sacciolepis pungens and Sporobolus cubensis. The counts of 2n = 80 for Paspalum secans and 2n = 20 for Axonopus affinis differ from the single previous record for each of these species.     

CHROMOSOME NUMBERS IN WESTERN GRASSES

Chromosome numbers are reported for 221 collections from eleven western states. These records represent 85 species included in 48 genera. Counts for the following species are here presented for the first time: Melica spectabilis, Blepharidachne kingii, Eragrostis obtusijlora, Hilaria rigida, Redfieldia flexuosa, and Sporobolus interruptus. The record for Redfieldia is also the first for that genus. In addition, numbers which differ from those in the literature are recorded for ten species, in three cases two different numbers for the same taxon. Cytological evidence is also presented indicating that Hilaria jamesii and H. rigida have hybridized and that the F₁ has backcrossed to both parents.     

SOME CHROMOSOME NUMBERS OF DRAPARNALDIA

The variability exhibited by Draparnaldia both in nature and in the laboratory makes it difficult to identify the species. The natural variability of Draparnaldia was amplified by the environmental conditions and the media used in this study. With the hope that chromosome studies would aid in taxonomic characterization by providing additional differentiating criteria, special attention was devoted to adapting techniques which could be used to determine chromosome numbers of Draparnaldia isolates. The chromosome numbers reported herein are as follows: (1) Draparnaldia glomerata, Isolate #1, isolated from Davis Falls, Montevallo, Alabama, was found to have a chromosome number of 13. (2) Draparnaldia Isolate #2, an unidentified species obtained from Anniston, Alabama, was found to have a chromosome number of 13. (3) Draparnaldia acuta, Isolate #3 from Northwood Lake, Northport, Alabama, exhibited 26 chromosomes. (4) Draparnaldia plumosa strain 423 (Indiana Culture Collection), 418/a (Cambridge) was observed to have a chromosome number of 13.     

CHROMOSOME NUMBERS IN SOUTHWESTERN GRASSES. II

Gould , Frank W. (Texas A. & M. Coll., College Station.) Chromosome numbers in southwestern grasses. II. Amer. Jour. Bot. 47(10): 873–877. Illus. 1960.—Chromosome counts are reported for 45 species of grasses of Southwestern United States and adjacent areas of United States and Mexico. Thirty-three of these records are the first for the taxon or different from previously reported and 7 are the first for North American plants.     

CHROMOSOME NUMBERS OF THE EAST AFRICAN GIANT SENECIOS AND GIANT LOBELIAS AND THEIR EVOLUTIONARY SIGNIFICANCE

The gametophytic chromosome number for the giant senecios (Asteraceae, Senecioneae, Dendrosenecio) is n = 50, and for the giant lobelias (Lobeliaceae, Lobelia subgenus Tupa section Rhynchopetalum) it is n = 14. Previous sporophytic counts are generally verified, but earlier reports for the giant senecios of 2n = 20 and ca. 80, the bases for claims of intraspecific polyploidy, are unsubstantiated. The 14 new counts for the giant senecios and the ten new counts for the giant lobelias are the first gametophytic records for these plants and include the first reports for six and four taxa, respectively, for the two groups. Only five of the 11 species of giant senecio and three of the 21 species of giant lobelia from eastern Africa remain uncounted. Although both groups are polyploid, the former presumably decaploid and the latter more certainly tetraploid, their adaptive radiations involved no further change in chromosome number. The cytological uniformity within each group, while providing circumstantial evidence of monophyly and simplifying interpretations of cladistic analyses, provides neither positive nor negative support for a possible role of polyploidy in evolving the giant-rosette growth-form.     

CHROMOSOME NUMBERS IN SOUTH AMERICAN COMPOSITAE

Original chromosome counts are reported from 91 populations and 73 taxa distributed among 46 genera. Most of these were obtained from meiotic material and are first reports. Some of the more interesting counts are from genera with amphitropical distributions such as Gaillardia and Helenium. When appropriate, systematic implications of the data are discussed.     

CHROMOSOME NUMBERS OF SOME SACCHARUM SPECIES HYBRIDS AND THEIR CELL SUSPENSION CULTURES

Chromosome numbers of five Saccharum species hybrids and their cell suspension cultures were determined. The chromosome number was stable in four parental clones (2n = 122, 114, 114, and 112), but was variable in another (2n = 108-128). The cell suspension cultures have been maintained in a yeast extract-enriched nutrient medium for more than 6 years. These cultures were variable in chromosome number for all clones, with a partial aneuploid series at the haploid and/or polyploid level. Each clone had different chromosomal population modes after 6 years of culture. The loss of chromosomes over a period of time would have an effect on the genetic makeup of a cell population. This has implications in the use and interpretation of data from pathological, cytogenetical, biochemical, and physiological studies using cell cultures and is probably a partial explanation for the loss of totipotency in 6-year-old sugarcane tissue and suspension cultures.     

FORAGING PATTERNS OF SOME SOUTH AFRICAN FLYCATCHERS

Fraser, W. 1983. Foraging patterns of some South African flycatchers. Ostrich 54:150-155.

The foraging behaviour of eight species of flycatchers found in South Africa was studied. Four feeding techniques were recognized: hawking, hawking-gleaning, gleaning and pouncing. The Chinspot Batis Batis molitor, Pririt Batis Batis pririt, Paradise Flycatcher Terpsiphone viridis and the Leadcoloured Flycatcher Myioparus plumbeus use hawking-gleaning as their main feeding technique and forage predominantly within the canopy of the vegetation. The Fiscal Flycatcher Sigelus silens, Black Flycatcher Melaenornis pammelaina and Marico Flycatcher Melaenornis mariquensis use pouncing as their main feeding technique and forage outside the canopy. The Spotted Flycatcher Muscicapa striata uses hawking as its main feeding technique and also forages outside the vegetation. While foraging the canopy-feeders are active and continually on the move through the vegetation in their search for prey whereas those foraging outside the vegetation are far less active and employ still-hunting, waiting for their prey to appear.     

非洲和中国直立人某些颅骨特征的比较--中国与非洲人类头骨特征对比之一

针对学术界有关非洲与亚洲直立人关系的争论,本文对一些用来支持非洲早期直立人从直立人中分离出来而归入匠人的主要形态学证据进行了检验,用于研究的标本包括迄今在东非发现的年代最早的直立人KNM－ER 3733、KNM－ER 3883和KNM－WT15000头骨化石,这些石是被提倡非洲与亚洲的直立人分离两个种的学者归入匠人的主要标本,对这些非注早期直立人与中国直立人18项头骨特征对比显示：一些被认为是局限于亚洲直立人的独有特征在上述非洲直立人头骨都有出现,存在于非洲直立人与中国直立人之间的颅骨特征上的差别主要体现在特征的表现程度与方式的不同,作者认为根据本文对比的颅骨特征,非洲直立人与中国直立人在颅骨形态上非常相似,他们之间的形态差异反映了直立人具有较宽的形态变范围,认为亚洲直立人具有特化的衍生性状的观点在本文不能得到支持。     

青藏高原东北部植物染色体数目和多倍性研究

对青藏高原东北高山冰缘地区和相邻低海拔地区５９种多年生草本被子植物进行了染色体计数。其中,４５个种的染色体记数为首次报道,并确定其倍性。对分布于高山冰缘地区和冰缘以下不同海拔地区植物染色体的多倍性进行分析研究。     

苍耳Xanthium strumarium L. 染色体数目和核型的观察

苍耳Xanthium strumarium L.(X. sibiricum Patr. ex Widder, X. iaponicum Widder)为菊科苍耳属的一年生草本,广布于欧亚大陆和北美洲;我国各地也均有分布。苍耳为常用中药,其果实入药,能发汗通窍、祛风湿,解表镇痛,用于治风湿性关节痛及鼻炎等症。     

CHROMOSOME NUMBERS IN PURE AND GROSS CULTURES OF MYXOMYCETES

Certain strains of Myxomycetes grown in pure culture in liquid media display widely varying chromosome numbers which indicate the presence of polyploid series of amoebae and plasmodia. The implications of these chromosome number variations on existing controversies concerning Myxomycete life cycles and cytology are discussed.     

CHROMOSOME NUMBERS IN CHEILANTHES AND POLYPODIUM

Six chromosome observations are reported, two being confirmations and four being new counts. Polypodium plesiosorum (from Mexico) shows 37 pairs at meiotic metaphase and thus conforms to past counts of diploid species in this genus. Cheilanthes wrightii (Arizona) has 2n = 58 and is a diploid member of the x = 29 series of that genus. Cheilanthes tomentosa (Alabama) shows 90 units at metaphase of meiosis and approximately the same number during mitosis in the crozier cells. It has 32 spores and our plant is an apogamous triploid. Both Cheilanthes siliquosa (Washington) and C. californica (California) show 30 pairs at meiotic metaphase. Counts on plants identified as C. carlotta-halliae (California) show 30 bivalents and 30 univalents at diakinesis, suggesting that they actually represent allopolyploid backcrosses of C. carlotta-halliae and one of its parents.     

苍耳X anthium strumarium L.染色体数目和核型的观察

苍耳Xanthium strumarium L. (X. sibiricum Patr. ex Widder, X. iaponicum Widder) 为菊科苍耳属的一年生草本,广布于欧亚大陆和北美洲;我国各地也均有分布。苍耳为常用中药,其果实入药,能发汗通窍、祛风湿,解表镇痛,用于治风湿性关节痛及鼻炎等症。     

广西广义山蚂蝗属部分种类的核型及染色体数目报道

本文分析了广义山蚂蝗属６种１变种的核型,并报道了９种１亚种的染色体数目。假地豆Ｄｅｓｍｏｄｉｕｍｈｅｔｅｒｏｃａｒｐｏｎ（Ｌ．）ＤＣ．,伏毛假地豆Ｄ．ｈｅｔｅｒｏｃｏｒｐｏ。（Ｌ．）ＤＣ．ｖａｒ．ｓｔｒｉｇｏｓｕｍｖａｎＭｅｅｕｗｅｎ,单叶假地豆Ｄ．ｒｕｂｒｕｍ（Ｌｏｕｒ．）ＤＣ．．金钱草Ｄ．ｓｔｙｒａｃｉｆｏｌｉｕｍ（Ｏｓｂｅｃｋ．）Ｍｅｒｒ．及假木豆Ｄｅｎｄｒｏｌｏｂｉｕｍｔｒｉａｎｇｕｌａｒｅ（Ｒｅｔｚ．）Ｓｃｈｉｎｄｌ．的核型均为Ｋ（２ｎ）＝２２＝２２ｍ,属１Ａ类型．但它们的染色体相对长度变化范围有一定的差异,假木豆的较大,假地豆的较小。舞草Ｃｏｄｏｒｉｏｃａｌｙｘｍｏｔｏｒｉｕｓ（Ｈｏｕｔｔ．）Ｏｈａｓｈｉ和圆叶舞草Ｃ．ｇｙｒｏｉｄｅｓ（Ｒｏｘｂ．ｅｘＬｉｎｋ．）Ｈａｓｓｋ．的核型为Ｋ（２ｎ）＝２２＝２２ｍ,有的细胞可见随体染色体,属１Ｂ类型．根据核型资料比较．作者发现狭义的舞草属比狭义的山蚂螟属和假木豆属较为进化。本文还报道大叶山蚂蝗ＤｅｓｍｏｄｉｕｍｌａｘｉｆｌｏｒｕｍＤＣ,波叶山蚂蝗Ｄ．ｓｅｑｕａｘＷａｌｌ．绒毛山蚂蝗Ｄ．ｖｅｌｕｔｉｎｕｍ（Ｗｉｌｌｄ．）ＤＣ,异叶山绿豆Ｄ．ｈｅｔｅｒｏｐｈ?