Verticil


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Related to Verticil: vertical definition

Verticil

 

(also whorl), a group of three or more leaves, branches, flowers, flower parts, or other plant organs arranged in a circle about the same point on the axial organ.

References in periodicals archive ?
0.5-0.75 mm wide; internodes 20 mm apart, bearing verticils with 8 to 12, widely spaced leaves all of similar length, linear-lanceolate, widely attached at the base and slightly pointed.
REMARKS: Bell (1944) included in Annularia aculeata specimens with verticils showing considerable variation in the number, size and shape of leaves.
DIAGNOSIS: Anisophyllous verticils flattened in spread out condition; 20-24 linear-lanceolate leaves, up to 85 mm long and 1.5-2 mm broad.
DESCRIPTION: Ultimate axes 2-5 mm wide, with internodes 16-45 mm apart bearing slightly overlapping verticils which are flattened in spread-out condition; anisophyllous (slightly elliptical), with the lateral leaves longer than those situated in lower and upper parts.
Annularia spinulosa also possesses slightly anisophyllous verticils with a similar number of leaves, but these are shorter (around 30 mm), lanceolate, with bluntly pointed apices; length/breadth ratio is lower.
The cylindrical strobili of Asterophyllites grandis possess bracts similar to the vegetative leaves, and sporangiophores situated at about middle distance between verticils.
Verticils with up to 16 closely placed, linear-lanceolate leaves, showing nearly parallel margins and an acute apex; lower leaves attached at approximate right angles and curved at about mid-length; higher leaves are more or less straight and attached at acute angles.
9 (small stem with verticils of long, overlapping, narrow leaves).
8 (incomplete verticils which cannot be assigned specifically, but clearly not belonging to this species).
Verticils with up to 20 filiform leaves with acute apices, adpressed in the axial plane, inserted at an acute angle (30-45[degrees]), and overlapping 2-4 internodes.
COMPARISONS: Asterophyllites longifolius is easily recognized by its long, filiform leaves that overlap several verticils.
Penultimate branch bearing verticils with the characteristic stiff, narrow, small leaves.