In leaflets on the rachis of the same the case of Medullosa anglica we leaf.
Spikelets one-flowered, rarely two-flowered as in Zea, falling from the pedicel entire or with certain joints of the rachis at maturity.
The distal ends of these girdles give off several branches, which traverse the petiole and rachis as numerous collateral bundles.
The vernation varies in different genera; in Cycas the rachis is straight and the pinnae circinately coiled (fig.
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.
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 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.
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.
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.
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.