Stem and branches pinnate or bipinnate, the pinnae and pinnules alternate.
Branches simple, 2 to 3 inches long; pinnulesabout 1/4 inch.
In a frond nine inches long there are about thirty primary pinnae on each side, and in one of the middle pinnae about ten oblong-ovate obtuse pinnately-incised pinnules on each side.
They are similarly oblong-lanceolate and tripinnate, the ultimate pinnules being very numerous and rather more closely crowded than in the other species just referred to.
The pinnules are from a line to two lines long, and are adnate to the secondary rachis by a more or less decurrent base.
These ultimate pinnules are innumerable, and it is in allusion to their very great number in this and the allied species that the generic name Myriopteris was proposed by Fee for the group.
In the example selected for our plate the pinnules are oblong, obtuse and crenulate, or at most, crenately-toothed.
In large fronds the teeth of the pinnules are again crenately toothed; but in small specimens the pinnules themselves are entire, or but slightly toothed.
Inferior pinnules on the lower pair of pinnæ conspicuously elongated.
Pinnules divided into minute, densely crowded segments, the herbaceous margin recurved and forming an almost continuous indusium.
Fronds broadly triangular, ternate, one to three feet high or more, the widely spreading branches twice pinnate, the lower pinnules more or less pinnátifid.
Eaton), but the latter has broader fronds with the pinnules of the sterile fronds oblong-lanceolate, somewhat acute and strongly toothed or pinnatifid.
RUBÉLLUM has the sori distinct even when mature; its pinnules stand at a wide angle from the rachis of the pinna and are strongly toothed or pinnatifid with obtuse teeth.
Lower pinnules of the lateral divisions scarcely longer than the others.
Veins extending from the base of the pinnules like the ribs of a fan.
Pinnules lanceolate, strongly decurrent so that the pinnæ are merely pinnatifid.
Single pinnules rather larger than those of the pinnæ are placed over the free spaces of the rachis, as was pointed out by Brongniart.
When disturbed, the pinnules of the arms first contract, the arms straighten themselves out, and the whole gradually and slowly closes up.
When contracted, the pinnules are pressed against the arms, and the arms themselves shut against one another, so that the whole looks like a swash made up of a few long, coarse twines.
On the other hand, a polyp on the main stem may form a second bud which, instead of forming a pinnule by uniserial budding, produces by biserial budding a branch, from which pinnules arise as from the main stem (fig.
The pinnules never branch again, since in the uniserial mode of budding a polyp never forms a second polyp-bud.
In this way are formed the familiar feathery colonies of Plumularia, in which the pinnules are all in one plane, while in the allied Antennularia the pinnules are arranged in whorls round the main biserial stem.
The tetraspores occur singly, one at the top of each of the lower joints of the pinnules of the plumes.
One of these contains the pretty Feather Stars, which are distinguished by their long and slender 'arms,' usually ten or more in number, each of which bears a number of pinnules that give it quite a feathered appearance.
The spore-clusters are arranged in pairs, and the tetraspores are thinly scattered on the pinnules of the plumes.
These arms are capable of being moved freely in any direction, as are also the little more or less rigid pinnules appended to them.
Goeppert, which he does not appear to notice, the pinnules are articulated upon the stem, and leave scars where they have fallen off.
Lesquereux and Mr. Lacoe are from the Lower Carboniferous, and evidently represent a different species with similar slender pitted stems, often partially denuded of pinnules below; but the pinnules are much broader and more distant.
The pinnules are so articulated that they break off, leaving delicate transverse scars, and the lower parts of the stems are often thus denuded of pinnæ for the length of one or more inches.
Some of the specimens show so much carbonaceous matter as to indicate that the pinnules were of considerable consistency.
The pinnules are provided with sharp teeth, and it should be noted that they have nothing very decided in the way of stalks.
The pinnae are arranged in alternation on either side of the rachis, and these are divided into pinnules with blunt points.
The upper portion of the frond is pinnatifid, and in many of the higher pinnae it is only the pinnules nearest to the rachis that are distinct.
In very large fronds the pinnules are again divided; the frond is then said to be tri-pinnate.
These pinnules may be deeply lobed, and when this is the case each lobe is called a segment.
These are divided intopinnules which, in some cases, towards their bases are again divided.
The pinnules are blunt and somewhat oblong in shape; they have serrated edges, but do not bear any spines.
It should be noted that the lowest pairs of pinnules, those next to the rachis, are often much modified; they are always small, and in some cases the upper pinnules are missing.
The sori are very freely scattered on the lobes or pinnules at the back of the frond, and these are covered with the curious hooded indusia which were noticed in the last species.
The pinnules are also more definitely stalked in the former than in the latter.
In a fair-sized example the frond is twice pinnate, the pinnae are definitely stalked, and the pinnules are roughly wedge-shaped, being somewhat toothed at the lip.
The fronds are twice pinnate, the pinnules being oblong with uncut edges.
In the case of a fertile frond the edges of the pinnules are turned back in a very striking way.
The pinnules are rather blunt, and frequently show serrated edges.
The pinnae are placed alternately on either side of the main stem, and these bear pinnules which have their margins deeply cut.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "pinnules" in a variety of sentences. We hope that you will now be able to make sentences using this word.
