Seed, attached to a branch of the rachis bearing two vegetative leaflets.
With regard to birds and land shells the relation is much closer to the Comoros species, and the latter, of which I have collected seven species besides Rachis aldabrae, may serve to point out more than the birds the land connexion of Aldabra with the neighbouring countries."
The ripe ears of the last hang so as to become almost parallel with the stem; they are narrower and longer than in (b), owing to the grains being placed farther apart on the rachis; it includes the Chevalier variety, one of the best for malting purposes.
All the flowers of each triplet of spikelets on both sides of the rachis are fertile and produce ripe fruits; hence the ear produces six longitudinal rows of grain.
All the flowers of each triplet are fertile as in (ii.), but the rows are not arranged regularly at equal distances round the rachis.
Not unlike the runner, though growing in a very different way, are the bud-plants formed on the fronds of several kinds of ferns belonging to the genera Asplenium, Woodwardia, Polystichum, Lastrea, Adiantum, Cystopteris, &c. In some of these (Adiantum caudatusn, Polystichum lepidocaulon) the rachis of the frond is lengthened out much like the string of the strawberry runner, and bears a plant at its apex.
In others (Polystichum angulare proliferum) the stipes below and the rachis amongst the pinnae develop buds, which are often numerous and crowded.
Spikelets one-flowered, rarely two-flowered as in Zea, falling from the pedicel entire or with certain joints of the rachis at maturity.
Rachis generally jointed and breaking up when mature.
Spikelets falling singly from the unjointed rachis of the spike or the ultimate branches of the panicle.
(3 Spikelets crowded in two close rows, forming a one-sided spike or raceme with a continuous (not jointed) rachis.
3); in Encephalartos, Dioon, &c., both rachis and segments are straight; in Zamia the rachis is bent or slightly coiled, bearing straight pinnae.
The distal ends of these girdles give off several branches, which traverse the petiole and rachis as numerous collateral bundles.
B, Section of the rachis bearing a single pinna.
8), the colony looks like a feather having a stem divisible into an upper moiety or rachis, bearing lateral central leaflets (pinnae), and a lower peduncle, which is sterile and imbedded in sand or mud.
The prorachidial and metarachidial aspects of the rachis are sterile, but the sides or pararachides bear numerous daughter zooids of two kinds - (I) fully-formed autozooids, (2) small stunted siphonozooids.
I, Rachis, or central stalk of ear, spikelets removed.
The primary axis of the inflorescence is sometimes called the rachis; its branches, whether terminal or lateral, which form the stalks supporting flowers or clusters of flowers, are peduncles, and if small branches are given off by it, they are called pedicels.
In describing a branching inflorescence, it is common to speak of the rachis as the primary floral axis, its branches as the secondary floral axes, their divisions as the tertiary floral axes, and so on; thus avoiding any confusion that might arise from the use of the terms rachis, peduncle and pedicel.
- Spike of Vervain (Verbena officinalis), showing sessile flowers on a common rachis.
- Amentum or catkin of Hazel (CorylusAvellana), consisting of an axis or rachis covered with bracts in the form of scales, each of which covers a male flower, the stamens of which are seen projecting beyond the scale.
It is, however, probable that a considerable group of true Ferns, allied to Marattiaceae, existed in Palaeozoic times, side by side with simpler forms. In one respect the fronds of many Palaeozoic Ferns and Pteridosperms were peculiar, namely, in the presence on their rachis, and at the base of their pinnae, of anomalous leaflets, often totally different in form and venation from the ordinary pinnules.
These curious appendages (Aphlebiae), at first regarded as parasitic growths, have been compared with the feathery outgrowths which occur on the rachis in the Cyatheaceous genus Hemitelia, and with the 'anomalous pinnules found in certain species of Gleichenia, at the points of bifurcation of the frond.
The sporangia were large pyriform sacs, shortly stalked, and borne in tufts on the branches of the fertile rachis, which developed no lamina.
Three sporangia borne on branchlets of the rachis.
In C, p is the palisade tissue of the rachis.
It is characteristic of Zygopteris and its near allies that two rows of pinnae were borne on each side of the rachis, at least in the fertile fronds.
On the fertile rachis the sporangia were borne in tufts, much as in the preceding genus; they were still larger, reaching 2.5 mm.
The seed was stalked, and there is an exact agreement in structure between the vascular strands of the stalk and cupule of the seed, and those of the rachis and leaflets of Lyginodendron, thus confirming the evidence from the glands.
27) it appears that the seed was borne on a leaf, or part of a leaf, reduced to a branched rachis.
Two seeds, enclosed in lobed cupules Some of the Medulloseae must and borne on branches of the rachis.
In leaflets on the rachis of the same the case of Medullosa anglica we leaf.
This Jurassic species bore bipinnate fronds not unlike those of the South African, Australian, and New Zealand Fern Todea barbara, which were characterized by a stout rachis and short broad pinnules bearing numerous large sporangia covering the under surface of the lamina.
In 61% of the samples there are barley grains and no rachis and in a further 31% barley grains outnumber rachis.
The spikelets are arranged in spike-like racemes, generally in pairs consisting of a sessile and stalked spikelet at each joint of the rachis (fig.
The young leaves of Cycas consist of a straight rachis bearing numerous linear pinnae, traversed by a single midrib; the pinnae are circinately coiled like the leaf of a fern (fig.
The vernation varies in different genera; in Cycas the rachis is straight and the pinnae circinately coiled (fig.
This was the case in Urnatopteris (Kidston), with Sphenopteroid sterile foliage; the sporangia, borne on the filiform pinnules of the fertile rachis, appear to have dehisced by an apical pore (fig.
In Stauropteris, a genus showing some affinity with Zygopteris, the branched rachis of the fertile frond terminates in fine branchlets, each bearing a single, spherical sporangium, without any differentiated annulus (fig.
Numerous pairs of pinnules are attached to the rachis of each sporophyll, and the larger pinnules bear 20 to 30 synangia (sori or plurilocular sporangia) (fig.
His successors, Rachis and Aistolf, attempted to follow the same game of conquest.
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