When the division is carried into the second degree, and the pinnae of a compound leaf are themselves pinnately compound, a bipinnate leaf is formed.
20) a sensitiveness is located in the pulvinus which upon irritation induces a depression of the whole bipinnate leaf, a similar property exists in the pulvini at the base of the leaflets which fold upwards.
In these plants the laminae or blades of the leaves are pinnate or bipinnate and are produced at the FIG.
- Leaf of an Acacia (Acacia heterophylla), showing a flattened leaf-like petiole p, called a phyllode, with straight venation, and a bipinnate lamina.
The Bunter sandstones of the Vosges have afforded several species of Lower Triassic plants; these include the Equisetaceous genus Schizoneura - a member also of the Glossopteris flora - bipinnate fern fronds referred to the genus Anomopteris, another fern, described originally as Neuropteris grandifolia, which agrees very closely with a southern hemisphere type (Neuropteridium validum, 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.
Bipinnate sterile fronds of Todites have in some instances been described under the designation Pecopteris whitbiensis.
Nebbense, Asplenites Roes- serti,&c.,have been given to bipinnate fronds of a type frequently met with in different genera and families of recent Ferns, e.g.
This type is distinguished by its large bipinnate fronds bearing long and narrow pinnae with close-set pinnules, characterized by the anastomosing secondary veins.
Dorsetshire and in the Inferior Oolite beds of Yorkshire, as well as in Rhaetic strata in Persia and elsewhere; it is characterized by its bipinnate fronds, and may be compared with the recent Australian genus Bowenia - peculiar among living Cycads in having bipinnate fronds.
6), recorded from several European localities, as well as from North America, Japan, China, Australia, India and Persia, affords an instance of a common type of bipinnate frond similar to Todites Williamsoni, which has been included in the Polypodiaceae; but such meagre evidence of the soral characters as we possess also points to a comparison with the recent fern Todea barbara.