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EXPLANATION OF TERMS. 



Hypsophyllary leaf. Same as hyp- 

 sophyll. 



Indefinite, (a) Of inflorescence : same as 

 racemose monopodial. (b} Of stamens : 

 more than twenty in androecium. Comp. 

 definite. 



Indehiscent. Not opening at one or more 

 fixed points to allow contents to escape. 

 Comp. dehiscent. 



Indusium. Outgrowth of a leaf covering 

 or surrounding one or more sporangia. 



Inferior ovary. Ovary from the summit of 

 which the floral leaves spring is termed 

 inferior. Comp. superior ovary. 



Inflorescence, (a) Mode of branching of 

 floral axis, (b} Branched floral axis. 



Innovation. In Muscineae : new shoot 

 which becomes independent by dying off 

 behind of parent shoot. 



Integument of ovule. Envelope to the 

 nucellus. 



Interfascicular cambium. Portion of a 

 cambial ring between the primary vas- 

 cular bundles. 



Interposition. In flower: development 

 of new members in a whorl between those 

 already formed. 



Intine. Innermost coat (endosporium) 

 of a pollen grain. Comp. exine. 



Intrapetiolar. Inclosed by the expanded 

 base of a petiole. 



Introrse. Anther with loculi turned to- 

 wards the centre of the flower is introrse. 

 Comp. extrorse. 



Involucel. Rosette of leaves surrounding 

 an ultimate branching of a compound 

 involucrate inflorescence. 



Involucrate. Having an involucre. 



Involucre, (a) In Anthoceroteae : tissue 

 of the thallus grown up around and over- 

 arching the embryo and subsequently 

 pierced by the elongating sporogonium. 

 (b} In Phanerogams : rosette of leaves 

 surrounding the base of an inflorescence. 



Irregular. Of flower: (a) a flower not 

 divisible into similar halves in any plane 

 is termed irregular. Same as asym- 

 metrical, (b} A flower divisible into 

 similar halves in only one plane is termed 

 irregular. Same as zygomorphous. By 

 English and French writers the term is 

 used to signify inequality in form and 

 size in members of the calyx or of the 

 corolla or of both. Comp. regular. 



Isogamous. Conjugation in which the 

 two coalescing gametes are of similar 

 form is isogamous. Comp. oogamous. 



Isostemouous. An androecium in which 

 the stamens are equal in number to the 

 petals and to the sepals (or to the latter 

 only in apetalous flowers) is isostemonous. 

 Comp. anisostemonous. 



Kathodic half of leaf. The half turned 

 away from the direction in which the 

 genetic spiral winds. Comp. anodic. 



Labellum. In Orchideae : enlarged and 

 irregularly shaped posterior member of 

 inner perianth whorl become anterior 

 by torsion of ovary through half-circle. 



Labium. In Isoetes : lip-like lower mar- 

 gin of foveola on the leaf. 



Lamella. In Hymenomycetes : vertical 

 plate on the under surface of the pileus 

 upon which the hymenium is extended. 



Lamina. Blade of leaf. 



Lateral plane. Of a flower or other lateral 

 structure : vertical plane at right angles 

 to the antero-posterior plane. 



Leaf-trace. Whole of common bundles in 

 a stem belonging to any one leaf, which 

 represent within the stem the anatomi- 

 cally demonstrable trace of the leaf. 



Legume. Monocarpellary unilocular cap- 

 sular fruit opening in dehiscence along 

 two lines. 



Leptosporangiate. Having sporangia 

 formed from a single cell. 



Lid-cells of archegonium. Terminal cells 

 of neck closing for a time canal of neck. 

 Same as stigmatic cells. 



Ligule. Appendage on anterior surface of 

 a leaf at point where lamina joins petiole 

 or sheath. See corona. 



Limb of petal. Lamina. 



Loculicidal. Dehiscence of a fruit along 

 median dorsal line of carpel is loculicidal. 



Lodicule. In Gramineae : small delicate 

 expansive scale inserted anteriorly on 

 torus outside base of stamens. 



Lomentum. Legume become plurilocular 

 by formation of spurious dissepiments. 



Macropodous. An embryo with enlarged 

 hypocotyl forming the greater part of its 

 mass is macropodous. 



Macrosporangium. Sporangium contain- 

 ing macrospores. Comp. microsporan- 

 gium. 



Macrospore. Large asexually produced 

 spore compared with others belonging to 

 same species. Comp. microspore. 



Macrozoospore. Large zoospore com- 

 pared with others belonging to same 

 species. Comp. microzoospore. 



Marginal ovule. Ovule borne on margin 

 of a carpel. 



Massula. (a) In Heterosporous Filicineae : 

 portion of hardened frothy mucilage 

 enclosing group of microspores. (b} In 

 Phanerogams : group of cohering pollen- 

 grains produced by one primary mother- 

 cell. 



Median plane. Of flower or other 

 lateral structure : same as antero- 

 posterior plane. 



