folded together lengthwise
folded face to face
• (a.) Folded lengthwise along the midrib, the upper face being within; -- said of leaves or petals in vernation or aestivation.
Folded together along its length, with each half flat.
<botany> Folded together, with the fold-line along the long axis (for example of cotyledons in a seed). ... (05 Jan 1998) ... 
Describing a leaf or modified leaf which is folded upward along the midrib.
Con·du'pli·cate adjective [ Latin conduplicatus , past participle of conduplicare . See Duplicate .] (Botany) Folded lengthwise along the midrib, the upper face being within; -- said of leaves or petals in vernation or æstivation. 
Two parts folded together lengthwise.
Type: Term Pronunciation: kon-dū′pli-kăt Definitions: 1. Folded on itself lengthwise.
folded face to face
foled lengthwise along the middle
(of a leaf in the bud) folded lengthwise with the upper face of the blade within.