[43] [Chapter V], and Organization of Tissues in [Chapter XXXVIII].
[44] Some of the different terms used to express the kinds of compound leaves are as follows:
Unifoliate (for a single leaflet, as in orange and lemon where the compound leaf is greatly reduced and consists of one pinna attached to the petiole by a joint). Bifoliate for one with two leaflets; trifoliate for one with three leaflets, as in the clover; plurifoliate for many leaflets. Odd pinnate for a pinnate leaf with one or more pairs of leaflets and one odd leaflet at the end.
So leaves are palmately bifoliate, etc., pinnately bifoliate, etc. Decompound leaves are those where they are more than twice compound, as ternately decompound in the common meadow rue (Thalictrum).
Perfoliate leaves are seen in the bellwort (Uvularia), connate perfoliate, as in some of the honeysuckles where the bases of opposite leaves are joined together around the stem. Equitant leaves are found in the iris, where the leaves fit over one another at the base like a saddle.
[45] The most remarkable case is that of the “telegraph” plant (Desmodium gyrans). Aside from the day and night positions which the leaves assume, there is a pair of small lateral leaflets to each leaf which constantly execute a jerky motion, and swing around in a circle like the second hand of a watch.
[46] Seedlings are usually very sensitive to light and are good objects to study.
[47] For a fuller discussion of this subject by the author see Chapters XLVI-LVII of his “College Text-book of Botany” (Henry Holt & Co.).
[48] οῖκος = house, and λόγος = discourse.
[49] Term used by Schimper.