二歧

Leaves basally cuneate, truncate, or subhastate; styles 2, free, achenes nearly orbicular, biconvex.

叶基部楔形，截形或者近戟状的；花柱2，离生，近圆形，双凸。 109 P 。 dichotomum 二歧蓼

A cyme having two lateral flowers or branches originating from opposite points beneath a terminal flower .

二歧聚伞花序一种聚伞花序，有两个侧花或两个侧枝，其生于顶生花下面两个相对的点

Branches 3-6 mm in diam.; inflorescence a compound dichasium or polychasium

分枝3-6毫米直径；花序一复合的二歧聚伞花序或多歧聚伞花序 32

Inflorescence a simple or compound monochasium, dichasium, simple or compound raceme, or flowers solitary.

花序单或者复合的单歧聚伞花序，二歧聚伞花序，单或者复总状花序或者单生花。

Male flowers 3 in a small dichasium, calyx present; female flowers without calyx; fruit a nutlet, winged; cotyledons flat.

雄花3在一小的二歧聚伞花序，花萼宿存；没有花萼的雌花；果一小坚果，具翅；子叶平。

Inflorescence a dichasium, arising from leaf axils near branch apex, long peduncled; flowers white, ca. 6 mm in diam.; sepals 5, base connate, ovate-oblong, ca. 3 mm long; petals 5, broadly orbicular, 2.5 times as long as sepals; stamens 10, exserted, up to 2 cm long.

二歧聚伞花序生於枝的近顶端叶腋部，具长的总花梗；花白色，直径约6毫米；萼片5片，基部合生，卵状长圆形，长约3毫米；花瓣5片，阔圆形，约长於萼片1.5倍；雄蕊10枚，伸出花冠外，长达2厘米。

Compound dichasium or corymbose polychasium. Flowers 4-merous.

复合的二歧聚伞花序或伞房状的多歧聚伞花序。

Inflorescence axillary, a compound dichasium; ultimate branches acicular.

花序腋生，一复合二歧聚伞花序；末级的分枝针状。

Female inflorescence pendulous or erect, with numerous overlapping bracts; each bract subtending a small dichasium with 2 or 3 flowers; calyx with 1-6 scalelike lobes, or obsolete; petals absent; ovary inferior, 2-loculed; styles 2, free; ovules 2, or 1 by abortion, pendulous from near apex of each locule.

雌花序下垂或直立，具多数重叠操作苞片；每苞片对着一小的二歧聚伞花序具2或3花；花萼具1-6鳞片状的裂片，或废退；花瓣无；子房下位，2室；花柱2，离生；胚珠2，或以败育，从近先端那里下垂具有每一个子房室。

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。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。