PETRIFIED PLANTS FROM THE UPPER MISSISSIPPIAN OF NORTH AMERICA. I: THE SEED RHYNCHOSPERMA GEN. N.
PETRIFIED PLANTS FROM THE UPPER MISSISSIPPIAN OF NORTH AMERICA. I: THE SEED RHYNCHOSPERMA GEN. N.
复制标题
DOI：
10.1002/j.1537-2197.1967.tb10724.x
复制
发表时间：
1967-09
影响因子：
3
通讯作者：
T. N. Taylor;D. A. Eggert
中科院分区：
文献类型：
--
作者：
T. N. Taylor;D. A. Eggert
在阿肯色州西北部的沉积物中描述了上密西西比时代的石化种子（切斯特系列）。奎尼根蛇精属的标本。Et sp. n.呈放射状对称，长度为1.2至2.2厘米，最大直径为1.0至1.3厘米。种子卵形，先端逐渐变细，具8-10被皮棱和宽圆的羽带。被膜分为两部分，包括一个可能是带有分泌管的外部软组织和一个由纵向定向的厚壁细胞构成的内层。珠心和被片是合流的，但在接近种子中层时，它们分开，珠心的自由部分形成一个圆顶状的花粉接收结构。其他特征，如脉管系统和结构保存完好的巨型蕨类植物进行了描述。将石化标本与为铸型和印痕建立的分类群进行比较，其中包括hynchogoniumand boroviczia。这些属的卵泡与卵泡的性质一直不确定，直到现在似乎在一个卵泡的身份得到解决。
Petrified seeds of Upper Mississippian age (Chester Series) are described from sediments from northwestern Arkansas. Specimens ofRhynchosperma quinniigen. et sp. n. are radially symmetrical and range in length from 1.2 to 2.2 cm and 1.0 to 1.3 cm at the greatest diameter. The seeds are ovate with a tapered apex having 8–10 integumentary ribs and a broadly rounded chalaza. The integument is two‐parted, consisting of an outer presumably soft tissue with secretory canals and an inner layer constructed of longitudinally oriented thick‐walled cells. Nucellus and integument are confluent, but they diverge near the seed midlevel with the free portion of the nucellus forming a dome‐shaped pollen‐receiving structure. Additional features such as vasculature and the structure of well‐preserved megagametophytes are described. The petrified specimens are compared with taxa instituted for casts and impressions which includeRhynchogoniumandBoroviczia.The ovulate versus cupulate nature of these genera which has remained uncertain until now appears to be settled in favor of an ovular identity.