羽状

As a result of analysis to many of the results of experiment, checked up on specimens, field investigation and combining with the theories of palaeobotany, comparative morphology, evolutional morphology of vascular plants and taxonomy, it can be concluded as following: the primitive sorts of Cycadaceae are the sorts that pinnate leafs are dichotomy; among these, the sort that pinnate leafs are tripinnate-dichotomy is most primitive, from this sort gradually evolve to bipinnate-dichotomy, to only for monopinnate-dichotomy, from this sort evolve to the sorts that pinnate leafs are simply pinna; among the sorts of simply pinna, the species that segments of megasporophyll possess much more triplicate to monodichotomy are most primitive.

经过大量的实验结果分析、查阅标本和野外调查，结合古植物学、比较形态学、演化植物学和分类学等理论进行分析，认为苏铁科原始的类型为羽叶呈二歧状分叉的种类，其中最原始的又是羽叶呈三回二歧状分叉的种类，从这个羽叶类型逐渐演化出一回二歧状分叉的羽叶类型，再演化出羽叶为单羽状的类型；而单羽状叶的类群中，又以大孢子叶侧裂片具三回、二回及一回二歧状分叉数量多的种类为最原始，而侧裂片二歧状分叉数量少的为较进化，侧裂片无二歧分叉的如拳叶苏铁类为最进化的种类。

Leaves tufted; stipes stout, up to 1.2 m long, densely covered with golden brown hairs at base; lamina up to 2 m long and 1 m wide, tripinnatifid; pinnae alternate, sparsely spaced; pinnules linear-lanceolate, to 15 cm long and 1-2.5 cm wide, short-stipitate; ultimate lobes linear, more or less falcate, shallowly serrate, dark green and shining above, light green to glaucous below.

叶簇生；叶柄粗壮，长可达1.2米，基部亦密被金黄褐色毛；叶片长可达2米，宽达1米，三回羽状分裂；羽片互生，疏离；小羽片线状披针形，长达15厘米，宽1-2.5厘米，具短柄；末回裂片线形，略呈镰状，边缘有浅锯齿，上面深绿色，有光泽，下面灰白色。

Leaves crowded near apex of the trunk, spirally arranged; stipes dark brown, with sharp spines; lamina large, oblong, tripinnate; pinnae 17-20 pairs, alternate, longest one to 60 cm long, the basal one reduced; rachis short-spiny; pinnules 18-20 pairs, sessile or nearly so, lanceolate, to 10 cm long and 2.5 cm wide, divided almost to the costa; segments more or less falcate, toothed.

叶螺旋状排列，聚生於茎端；叶柄棕色，具锐刺；叶片大，长矩圆形，三回羽状深裂；羽片17-20对，互生，最大的长达60厘米，基部一对缩短，羽轴有短刺；小羽片18-20对，无柄或近於无柄，披针形，长达10厘米，宽2.5厘米，深裂几达中脉；末回裂片多少镰状，有齿。

Leaves tufted; stipes 3-10 cm long, glabrous, narrowly winged near apex; lamina oblong-ovate to triangular, generally 10-12 cm long, bi- or tripinnate; pinnae 3-5 pairs, oblong-ovate, sessile; rachis narrowly winged; pinnules pinnately dissected, segments linear.

叶簇生；叶柄长3-10毫米，无毛，近顶端有狭翅；叶片长卵圆形至三角形，通常长10-12厘米，二回或三回羽状分裂；羽片3-5对，互生或近对生，长卵圆形，无柄，羽轴有狭翅；小羽片羽状细裂；末回裂片细长，线形。

Leaves simple; petiole 1.5--4(--7) mm; leaf blade ovate or lanceolate in outline, pinnatipartite or pinnatisect, sometimes pinnatilobed, 0.5--5 × 0.3--3 cm, leathery, both surfaces sparsely puberulous or subglabrous, base cuneate or subtruncate; lobes in 1--3(or 4) pairs, undivided and linear or subrhombic and unequally 2- or 3-lobulate, 4--15 mm, apex acute; lobules ovate, triangular, or linear; midvein abaxially slightly prominent or flat, inconspicuous.

单叶 叶柄1.5-4(-7)毫米；叶片卵形或披针形轮廓，羽状深裂或羽状全裂，有时羽状浅裂的， 0.5-5 * 0.3-3 厘米，革质，两面稀疏被微柔毛的或近无毛，基部楔形或近截形；在对，不裂和线形或1-3(或4)内裂片和不相等2或3具小裂片，4-15毫米，先端锐尖；卵形，三角形的小裂片，或线形；中脉的背面的稍突出或平，不显眼。

Leaves pinnatifid or occasionally pinnatipartite, not pinnatisect.

叶羽状半裂的或偶有羽状深裂，不羽状全裂。

Lower leaves pinnatipartite, pinnatifid, or sinuate-dentate; fruit not torulose, with only stellate trichomes; subapical horns (2.5-)4-7(-8) mm, divaricate-reflexed, strongly recurved; valves extended beyond horns into stylelike apex 1-2 mm

下部叶羽状深裂，羽状半裂，或具深波状具牙齿；不近念珠状的果，具只星状毛；近尖端角(2.5-)4-7(-8)毫米，极叉开反折，强烈下弯；在进stylelike先端1-2毫米角状突起以外裂爿延伸 2 T。

Basal leaves rosulate; petiole 1-10(-15) cm; leaf blade broadly oblanceolate, oblong or lanceolate in outline, pinnatisect, pinnatifid, or runcinate,(2-)5-20(-35)×(1-)2-8(-10) cm; lateral lobes (3 or)4-6(-8) on each side of midvein, smaller than terminal one, oblong or lanceolate, entire, dentate, or lobed. Uppermost cauline leaves with narrowly linear to filiform lobes.

基生叶莲座状；叶柄1-10(-15)厘米；宽倒披针形的叶片，长圆形或披针形轮廓，羽状全裂，羽状半裂，倒向羽裂的或，( 2-)5-20(-35)*(1-)2-8(-10)厘米；侧面裂片(3或者)4-6(-8)在中脉两边各，最上部的茎生叶具狭线形到丝状裂片。

Fruiting pedicels erect or ascending, often subappressed to rachis, densely pubescent; racemes bracteate at least basally; stems prostrate or rarely ascending; uppermost leaves 1-pinnatisect or pinnatifid; fruit terete; ovules 10-16 per ovary

果梗直立或上升，通常近贴伏于轴，密被短柔毛；具苞片的总状花序至少基部；茎匍匐或很少上升；最上部的叶1羽状全裂的或羽状半裂；果圆柱状；每子房胚珠10-16 1 S。 annua 中亚羽裂叶荠

Leaves 1–4-pinnate or ternate-pinnate; ultimate segments serrate to incised or pinnate.

留下1-4羽状的或三出羽状；末回裂片有锯齿到锐裂的或羽状。

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。