174 GLOSSARY. 



Archegonium, pi. archegonia (beginning of offspring). The 



female organ of Bryophytes and Pteridophytes. 

 Archesporium (beginning of a seed). The cell or group of 



cells that initiates the spore-producing series. 

 Areola, pi. areolce (a small open space). The spaces in a reticu- 

 lated surface, as in the thallus of Marchantia. 

 Ascocarp (ascus fruit). The specialized body in which asci are 



formed. 



Ascospores (ascus seeds). The spores formed in an ascus. 

 Ascus, pi. asci (a sac or bag). The spore-sac of a large group 



of Fungi. 

 Asexual spore. A spore formed entirely independent of any 



cell union. 



Axial. Relating or belonging to the axis. 

 Axil (the armpit). The angle just above the attachment of 



a leaf to the stem. 

 Axis (the pole). The central part or longitudinal support on 



which organs or parts are arranged. 

 Bast. In general, the phloem region of a fibro- vascular bundle; 



or, specifically, the fibres of the phloem. 

 Bract (a thin plate). The more or less modified leaves of a 



flower-cluster. 

 Bryophyta (moss-plants). A primary division of plants, named 



from its principal group, the mosses. Bryophyte is the 



English equivalent. 

 Callus (hard skin). A hardened or thickened place; technically 



used of the thickening mass in a sieve-plate, usually ap- 

 pearing as a layer on each side of the plate. 

 Calyptra (a cover). In mosses, the hood which covers the 



capsule. 

 Calyx (a cup). The outer envelope of a flower, composed of 



sepals. 



Cambiform. Resembling cambium. 

 Cambium (exchange). The meristem cells of a fibro- vascular 



bundle, lying between the phloem and xylem, which 



retain the power of cli . 

 Campylotropous (turned or curved). Said of an ovule or seed 



which becomes curved in its growth so as to be inverted. 

 Capsule (a small box). A dry dehiscent seed-vessel (formed of 



more than one carpel); or a similar spore- vessel. 

 Carpel (fruit). The im-gasporophyll; hence either a simple 



pistil, or one of the parts of a compound pistil. 



