1) Simple 2) Unsubdivided 1) Unsubdivided 
with its base wrapped around the stem (so that the stem appears to pass through it), e.g. of leaves and bracts.
with basal lobes united and encircling the stem, commonly referring to a leaf where the stem runs through the leaf base
• (a.) Having the basal part produced around the stem; -- said of leaves which the stem apparently passes directory through. • (a.) Surrounded by a circle of hairs, or projections of any kind.
the stem apparently piercing the leaf or surrounded by basally joined opposite leaves
Paired leaves which fuse around the stem.
A leaf that appears to be perforated by the stem.
Of a sessile leaf or bract, having its base completely wrapped around the stem. ... (09 Oct 1997) ... 
the stem apparently piercing the leaf or surrounded by basally joined opposite leaves
With the leaf base completely encircling the stem.
Per·fo'li·ate adjective [ Prefix per- + Latin folium leaf.] 1. (Botany) Having the basal part produced around the stem; -- said of leaves which the stem apparently passes directory through. 2. (Zoology) Surrounded by a circle of hairs, or projections of any...
The stem apparently passing through the part, as a leaf; united around the stem.
[adj] - of a leaf having the base united around (and apparently pierced by) the stem
adjective of a leaf having the base united around (and apparently pierced by) the stem
Paired leaves that fuse around the stem.