We will go so far as to say that it appears as though some Angiosperms arose in that way; but flowering plants show so many points utterly differing from the whole Cycadean stock that a little scepticism may not be unwholesome.
Their completely Cycadean appearance and their unique type of fructification have led many botanists to see in them the forerunners of the Angiosperms, to look on them as the key to that mystery--the origin of the flowering plants.
On Fossil Cycadean Stems from the Secondary Rocks of Britain," published in the Transactions of the Linnean Society, vol.
Thus the cycadean type does not really constitute an advance in grade of organisation in the Mesozoic, any further than that, in the period now in question, it becomes much more developed in number and variety of forms.
The Mesozoic flora of that island is of the usual conifero-cycadean type.
XVI) will speak for themselves and show how clearly Griffith had grasped the morphology of the Cycadean ovule, how faithfully he delineated the details, and how he sought in progressive development to throw light on the structure.
A papery remnant of nucellus lines the inner face of the woody shell, and, as in cycadean seeds, the apical portion is readily separated as a cap covering the summit of the endosperm.
In structure a cycadean sporangium recalls those of certain ferns (Marattiaceae, Osmundaceae and Schizaeaceae), but in the development of the spores there are certain peculiarities not met with among the Vascular Cryptogams.
Lang, "Studies in the Development and Morphology ofCycadean Sporangia, No.
The secondary wood of the shoot and root conforms in the main to the coniferous type; in the short shoots the greater breadth of the medullary rays in the more internal part of the xylem recalls the cycadean type.
Short and reticulately-pitted tracheal cells, similar to tracheids, often occur in the circummedullary region of cycadean stems.
A thorough examination of cycadean seeds has recently been made by Miss Stopes, more particularly with a view to a comparison of their vascular supply with that in Palaeozoic gymnospermous seeds (Flora, 1904).
Brongniart, who was the first to investigate in detail the anatomy of a cycadean stem, recognized an agreement, as regards the secondary wood, with Dicotyledons and Gymnosperms, rather than with Monocotyledons.
The vascular bundle entering the stem from a leaf with a single vein passes by a more or less direct course into the central cylinder of the stem, and does not assume the girdle-like form characteristic of the cycadean leaf-trace.
The vascular system of cycadean seedlings presents some features worthy of note; centripetal xylem occurs in the cotyledonary bundles associated with transfusion-tracheids.
From an evolutionary point of view, it is of interest to note the occurrence of filicinean and cycadean characters in the maidenhair tree.
During the increase in thickness of a cycadean stem successive layers of cork-tissue are formed by phellogens in the persistent bases of leaves (fig.
Before following the growth of the pollen-grain after pollination, we will briefly describe the structure of a cycadean ovule.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "cycadean" in a variety of sentences. We hope that you will now be able to make sentences using this word.
