pinnule's Usage Examples:

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.

Section of pinnule and synangium.

MAIDENHAIR, in botany, the common name for a fern, Adiantum Capillus-Veneris, characterized by the spreading hairlike branches of the frond, the ultimate pinnules of which are z to 1 in.

Or a polyp on the main stem, after having budded a second time to form a pinnule, may give rise to a third bud, which starts a new biserial FIG.

- Hydrothecae sessile, biserial on the main stem, uniserial on the lateral branches or pinnules, which give the colony its characteristic feathery form; with nematophores.

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.

Polyp 7 has proof sense, 1 o c oduced as its first bud, 8; as its second bud, a7, motion and nutriwhich starts a uniserial pinnule; and as a third t i on, until its bud I', which starts a biserial branch (I I'-VI') medusoid nature that repeats the structure of the main stem and and organization gives off pinnules.

F, foundersecond bud, which usually polyp; I, 2, 3, succession of polyps forms a side branch or pinnule budded from the founder.

5); the segments, which are broadly ovate or rhomboidal, have several forked spreading veins, and resemble the large pinnules of some species of Adiantum.

Solitary polyps are unknown in this sub-order; the colony may be creeping or arborescent in form; if the latter, the budding of the polyps, as already stated, is of the sympodial type, and either biserial, forming stems capable of further branching, or uniserial, forming pinnules not capable of further branching.

Arms fork once to thrice, and bear pinnules on each or on every other brachial.

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.

Food brought to the mouth by a subvective system of ciliated grooves, radiating from the mouth either between the plates of the theca (endothecal), or over the theca (epithecal), or along processes from the theca (exothecal: arms, pinnules, 'c.