A frond that is only once-pinnate may seem at first glance twice-pinnate, as its pinnae may be so deeply lobed or pinnatifid as to require a close examination to convince us that the lobes come short of the midvein of the pinnae.
A frond is once-pinnate when the incisions extend to the midvein (Fig.
A frond is pinnatifid when cut so as to form lobes extending half-way or more to the midvein (Fig.
Under these conditions the midvein is called the rachis (a), and the divisions are called the pinnae (b).
The sori are rather large, placed nearer the midvein than the margin, and are rarely produced towards the apex of the segments.
They fork once about midway between the midvein and the margin, and sometimes, especially in fertile fronds, a second time just within the margin.
Shrubs, with odd-pinnate leaves; the leaflets marked with minute dots, usually stipellate, the midvein excurrent.
On the middle of the midvein these leaves are seen to bear small clusters of flowers; indeed this is the only place where flowers are produced.
Likewise we must refrain from a consideration of the physiologic qualities of the tendril, and confine our attention to the combination of a limb, a naked midvein and an ascidium.
A frond is pinnátifid when its lobes extend halfway or more to the rachis or midvein as in the middle lobes of the pinnátifid spleenwort (Fig.
Fruit-dots large, round, half way between the midvein and the margin.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "midvein" in a variety of sentences. We hope that you will now be able to make sentences using this word.
