48o 



EXPLANATION OF TERMS. 



Foot. Development from hypobasal por- 

 tion of proembrj'o, serving as organ of 

 attachment and suction. 



Fovea. In Isoetes : depression on upper 

 surface of leaf-sheath in which the 

 sporangium is formed. 



Foveola. In Isoetes : small depression 

 above the fovea in the leaf, from out of 

 which the ligule springs. 



Fovilla. Contents of the pollen-grain. 



Frondescence. Same as phyllody. 



Frondose. Same as thalloid. 



Fructification. In Cryptogams : any 

 sporogenous structure or collection of 

 sporogenous structures. In a limited 

 sense is the result of a sexual act but 

 in this book is used in its widest sense. 



Fruit. In Phanerogams : in limited sense, 

 is a pericarp containing seeds, i.e. an 

 ovary which has developed and become 

 changed physiologically by the effects of 

 fertihsation and which contains ripe 

 seeds : in a wider sense, is all those parts 

 whether of the flower itself or in its 

 vicinity which exhibit a striking change 

 after fertilisation and form a distinct 

 whole separate from the rest of the plant. 

 The term pseudocarp is applied to a 

 fruit consisting of other parts besides 

 the pericarp and seeds. 



Frutieose. Shrub-like. In Lichens : 

 forms are termed frutieose in which the 

 thallus is attached to the substratum at 

 one point only and by a narrow base, 

 from which it grows upwards with a 

 branching shrub-like habit. 



Fundamental spiral. Same as genetic 

 spiral. 



Fundamental tissue. Tissue not belong- 

 ing to the dermal or to the fascicular 

 system of tissues. 



Funietilua (funicule, fimicle). Stalk of 

 ovule. 



Funnel. InHeterosporousFilicineae: space 

 below the thick outer coats of the macro- 

 spore into which the apical papilla projects. 



Gamete. Sexual protoplasmic body, naked 

 or invested with a membrane, motile 

 (zoogamete or planogamete) or non- 

 motile, which on conjugation with another 

 gamete of like or unlike outward form 

 gives rise to a body termed zygote. 



Gamopetalous. Having cohering petals. 

 Same as monopetalous, sympetalous. 

 Comp. polypetalous. 



Gamopliyllous. Ha\'ing cohering leaves ; 

 said of the flower. 



Gamosepalous. Having cohering sepals. 

 Same as monosepalous, synsepalous. 

 Comp. polysepalous. 



Genetic spiral. Spiral line passing 

 through the point of insertion of all equi- 



valent lateral members on an axis, in order 

 of age from older to younger. Called 

 also generating spiral, fundamental 

 spiral. 



Germ-nucleus. Nucleus resulting from 

 coalescence of a sperm-nucleus (male 

 pronucleus) with the nucleus of an 

 oosphere or ovum (female pronucleus). 



Germ-tube. Tube of the endosporium put* 

 out in germination from a spore. 



Germinal vesicle. Oosphere (ovum) in 

 embryo-sac of ovule. 



Girdle. In Diatomaceae : overlapping 

 edges of the valves. 



Glans. Inferior achene with indurated 

 pericarp. Same as nut. 



Gleba. In Gasteromycetes: chambered hy- 

 menophorous portion in the 'fructification.' 



Globule. In Characeae : antheridium. 



Glochidium. In Heterosporous Filicineae : 

 barbed hair-like structure on the massulae, 

 serving to anchor them to a macrospore. 



Glumaceous. [a] Belonging to glumes. 

 [b) Of the consistence of glumes. 



Glume. In Gramineae : chafty leaf at 

 base of simple inflorescence or of each 

 branch of compound inflorescence. 



Gonidangium. Receptacle within which 

 gonidia are produced. 



Gonidial layer. In Lichens : layer of 

 algal cells in a heteromerous tha'lus. 



Gonidiophore. Single hypha or com- 

 pound body of hyphae on or in which 

 gonidia are formed. 



Gonidium. Same as brood-cell. In 

 Lichens : algal cell of thallus. 



Gonophore. Stalk supporting female and 

 male organs. 



Gonoplasm. In Peronosporeae: portion of 

 protoplasm of antheridium which passes 

 through fertilisation-tube and coalesces 

 with oosphere. Comp. periplasm. 



Growth-form. A vegetative structure 

 marked by some easily recognised fea- 

 ture of growth characterising individuals 

 or stages in the life cycles of types which 

 have no necessary genetic affinity. Thus 

 tree, shrub, sprout-fungus are growth- 

 forms. 



Gymnoearpous. In Fungi : forms with 

 the hymenium exposed when the spores 

 are maturing are gymnoearpous. Comp. 

 angiocarpous. 



Gymnostomous. In Musci : forms in 

 which the capsule has no peristome 

 are gymnostomous. 



Gynaeceum. Series of carpels (fema4e 

 sporophylls) in a flower. 



Gynobasic. A style adhering by its base 

 to a prolongation upwards of the torus 

 between carpels is gynobasic. 



Gynophore. Stalk supporting a female 

 organ. 



