平行脉的

The results of character evolution history reconstruction shows the SC in PT and AD clade might be a homoplasy character; also, the SC in PT clade might have multiple origins. SC in Pteridaceae has some special characteristics:(1) the cell long axes usually run parallel to the lateral veins;(2) Most of Pteris and Adianum species have VSC only in lower epidermis;(3) Species have ISC also have VSC.(4) Presence of spicular cells is highly correlated with the long veinal epidermal cells. Species have type III silica deposition type usually have longer and narrower veinal epidermal cell compared with ordinary epidermal cells; Species have type IV silica deposition type also have long epidermal cells, but not significantly different from ordinary epidermal cells.

本实验中亦发现凤尾蕨科之矽异形细胞具有几项特色：(1)矽异形细胞之长轴多与叶片侧脉方向平行(2)发现多数铁线蕨属以及凤尾蕨属植物仅下表皮具有脉上矽异形细胞；(3)具有脉间矽异形细胞的种类会同时具有脉上矽异形细胞；(4)长条形的侧脉上表皮细胞与矽异形细胞具有相关性，仅具脉上矽异形细胞的分类群之脉上表皮细胞均较一般表皮细胞细长；具有脉间矽异形细胞之物种之脉上表皮细胞亦为长条形但形态与一般表皮细胞常无明显形态差异。

In particular, by introducing the force constraint between midrib and parallel venation, the dynamic simulation of leaves can be vividly performed.

针对以往研究中植物建模主要集中在对植物器官静态结构的仿真，通常会忽略树叶或花瓣的厚度问题，本文根据阔叶植物的自然属性，利用植物的茎枝和叶片结构的相似性，采用具有厚度信息的3D叶片建模方法，通过叶片平行脉位置方向的弹性约束关系来有效控制叶片的动态仿真。

Leaves petiolate; leaf blade papery to membranous, secondary veins 1 or 2 on each side of midvein, tertiary veins parallel, margin usually serrulate.

叶具叶柄叶片纸质到膜质，次脉在中脉两边各1或2，平行的第三脉，边缘通常有细锯齿的。

Fruit indehiscent, samaroid silicles, transversely oblong or ovoid, 1-seeded, thin walled, with woody and coarsely reticulate venation, angustiseptate, sessile, transversely 2-winged, 2-16-spined; wings prominent, longer or shorter than main part of fruit, with 3-20 subparallel veins extending full length; spines often unequal in length, at least some subparallel to pedicel, those on the seed-bearing fruit half longer; replum and valves margin united into a longitudinal vein; septum complete; style absent, obsolete, or conical and to 5 mm; stigma capitate, entire, long papillate.

果不裂，突出的翅，长或短于主要果，具3-20近平行脉深裂延长全长；刺通常不等长，在花梗，那些在种子取得成果半长上近平行的一些的至少；假隔膜和阀门边结合成为一纵向脉；隔膜完全；花柱无，废退，或者圆锥状和对5毫米；柱头头状，全缘，长具乳突。

Leaves parallel veined, without clear, transverse venation between main veins; filaments not forming a ring.

平行脉的叶，没有清楚，在主脉之间的横向脉序；花丝不形成一枚戒指。

They all have the typical structure of leaf of C4 plant, but out of the ordinary is that the structure of the midrib is alike the parallel veins and there is a layer of fiber cells between the phloem and the bundle-sheath of vein in the midrib and big parallel veins while the outer wall of the bulliform cells is less cuticularized.

摘 要：以7个杂交狗牙根品种的叶片进行解剖研究，结果表明，各品种均具禾本科 C4植物叶片典型结构，其独特处是：中脉结构与平行脉相似；中脉维管束、平行脉大维管束的维管束鞘内侧韧皮部外有一层纤维细胞；泡状细胞外壁很少角化。

Stipules (2-)3-5 mm; petiole 3-5 mm, sulcate adaxially; leaf blade narrowly lanceolate or narrowly elliptic, 7-15 × 1.5-3 cm, chartaceous, glabrous on both surfaces, base narrowly cuneate, margin with dense and unequal glandular teeth, apex acuminate; midvein prominent on both surfaces; secondary veins numerous,± parallel; veinlets

托叶(2-)3-5毫米；叶柄3-5毫米，正面具槽；叶片狭披针形的或狭椭圆形， 7-15 * 1.5-3 厘米，纸质的，两面无毛，基部狭楔形，边缘具紧密的和不等长的具腺的齿，先端渐尖；中脉的两面突出；次脉多数，多少平行；细脉

Leaves petiolate; leaf blade secondary veins 2-4 on each side of midvein, tertiary veins parallel, margin entire or denticulate.

叶具叶柄叶片次脉2-4在中脉两边各，平行的第三脉，边缘全缘或具小齿。

However, the complexity of data generation and operation coordination/synchronization of these parallel arithmetic units is prohibitive in most embedded systems.

但如何有效率地在这些平行操作的运算单元间进行资料传输及交换，同时提供其在每时脉所需要的运算元则是极大的挑战。

Like most monocots, orchids generally have simple leaves with parallel veins, although some Vanilloideae have a reticulate venation.

就如同大部分的单子叶植物，兰科植物通常具有有平行脉的单叶，尽管一些香荚兰亚科植物具有网状叶脉。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。