474 



EXPLANATION OF TERMS. 



usually continues to grow after their for- 

 mation are termed by Leitgeb anacrogy- 

 nous. Comp. acrogynous. 



Analogous. Having the same function. 



Anatropous. An ovule is anatropous when 

 the nucellus is straight, but its apex and 

 therefore also the micropyle is turned 

 through a half-circle towards the funicu- 

 lus, which in its upper part extends along 

 the whole length of the ovule united 

 with the integument as the raphe. Same 

 as inverted. 



Androecium. Series of stamens (andro- 

 phylls, male sporophylls) of a flower. 



Androphore. Stalk supporting an androe- 

 cium. 



Androphyll. Stamen, a male sporophyll. 



Androspore. In Oedogonieae: swarm- 

 spore giving rise to very small short-lived 

 plants (dwarf-males) destined to produce 

 spermatozoids. 



Anemophilous. Pollinated by the agency 

 of wind. Comp. zoidiophilous, hydro- 

 philous. 



Angiocarpous. In Ascomycetes and 

 Basidiomycetes : forms in which the 

 hymenium is disposed inside the tissue 

 of the sporocarp are angiocarpous. 

 Comp. gymnoearpous. 



Anisostemonous. An androecium in 

 which the stamens are not equal in 

 number to the petals and to the sepals (or 

 to the latter only in apetalous flowers) is 

 anisostemonous. Comp. isostemonous. 



Annulus. (a) In Musci : annular layer 

 of epidermal cells surrounding the line 

 of separation of the operculum from the 

 capsule and thrown off as the operculum 

 is detached, (b) In Filices : row of special 

 cells running transversely obliquely or 

 vertically in the wall of the sporangium ; 

 the cells by contraction in drying cause 

 the rupture of the capsule at right angles 

 to the axile plane of the annulus. (c) In 

 Equisetaceae: imperfectly developed foliar 

 sheath below the sporangiferous spike. 



Anodic half of leaf. The half turned in 

 the direction in which the genetic spiral 

 winds. Comp. kathodic. 



Anterior. Of a flower or other lateral 

 structure : the side turned away from the 

 parent-axis is anterior. Comp. posterior. 



Antero-posterior plane. Of a flower or 

 other lateral structure : vertical plane 

 bisecting the anterior and posterior sides 

 and if prolonged passing through the 

 centre of the parent-axis. Same as 

 median plane. 



Anthela. Cymose monopodial inflores- 

 cence in which lateral axes are formed 

 in indefinite number on each axis that 

 terminates in a flower ; the lateral shoots 

 growing vigorously overtop the primary 



axis and develope in such a manner 

 that the entire inflorescence does not 

 acquire any definite outline. 



Anther. The pollen-sacs (microsporangia) 

 borne upon the staminal leaf are collec- 

 tively termed the anther. 



Antheridium. Male sexual organ of 

 various form and position, in most cases 

 producing in its interior planogametes 

 (spermatozoids). (a) In Rhodophyceae 

 the ' antheridium ' produces motionless 

 gametes (spermatia). (b~) In some Fungi 

 the antheridium (formerly termed polli- 

 nodium) is the delimited extremity or 

 other portion of a hyphal branch, and its 

 contained protoplasm is conveyed within 

 the antheridium to the receptive organ. 



Anticlinal. Directed towards or cutting 

 at right angles the circumference of a 

 part. Comp. periclinal. 



Antipetalous. Opposite to or superposed 

 on, i. e. not alternating with a petal. 



Antipodal cells. In Angiosperms : three 

 cells at the base of the embryo-sac formed 

 by division of the primary nucleus of the 

 embryo-sac. 



Antisepalous. Opposite to or superposed 

 on, i. e. not alternating with a sepal. 



Apetalous. Having no petals. 



Apocarpous. Having two or more sepa- 

 rate carpels. Comp. syncarpous. 



Apogamy. Loss of sexual function ; when 

 sexual organs though present are function- 

 less, nevertheless the normal product 

 of the sexual act is developed from 

 the oosphere (ovum) or from the female 

 sexual organ or from its vicinity. See 

 parthenogenesis. Comp. apospory. 



Apophysis. In Musci : enlargement 

 of the seta beneath the capsule. 



Apospory. Loss of sporogenous function ; 

 when sporogenous organs though present 

 are functionless, and the normal product 

 of germination of the spore developes 

 directly from the sporogenous organ or 

 from its vicinity. Comp. apogamy. 



Apothecium. In Ascomycetes : ascocarp in 

 which the hymenium lies exposed when the 

 asci are maturing. Same as discocarp. 



Archegoniate. Having archegonia. 



Archegonium. Female sexual organ with 

 narrow upper portion (neck) pierced by 

 a canal usually enclosing one or more 

 cells (neck-canal-cells) and leading to a 

 basal dilated portion (venter) containing 

 one oosphere (ovum) and a smaller cell 

 at the entrance of the neck-canal (ventral 

 canal-cell). After fertilisation the embryo 

 is developed within the venter. 



Archesporium. In Archegoniatae: cell or 

 group of cells from which spore-mother- 

 cells are formed. 



Archicarp. Literally commencements of 



