GLOSSARY. 183 



Proembryo (going before the embryo). In Spermatophytes, 

 the chain of cells (suspensor) formed after fertilization, 

 and from the lower end of which the embryo develops 

 See Suspensor. 



Prothallium, pi. prothallia (a forerunning shoot). The small, 

 usually short-lived plant which develops from the spore 

 and bears the sex-organs. 



Protonema, pi. protonemata (that which is first sent out). In 

 mosses, the filamentous growth which is produced by the 

 spores, and from which the leafy moss-plant is developed. 



Protophyta (the first plants). A primary division of plants 

 named from the fact that they include the lowest known 

 plants. Protophyte is the English equivalent. 



Protoplasm (that which is first formed). The living matter of 

 cells. 



Pteridoid. Fern-like. 



Pteridophyta (fern-plants). A primary division of plants, 

 named from its principal group, the ferns. Pteridophyte 

 is the English equivalent. 



Pyrenoid (kernel-formed). Minute colorless bodies imbedded 

 in the chlorophyll structures of some lower plants. 



Raphides (needle-formed). Needle-like plant-crystals. 



Receptacle. That portion of an axis or pedicel (usually 

 broadened) which forms a common support for a cluster 

 of organs, either sex-organs or sporophylls. 



Reticulated (net-like). Having a net-like appearance. 



Rhachis (the backbone). The axis of a compound leaf, or 

 of a spike. 



Rhaphe (a seam). In an anatropous ovule, the ridge which 

 connects the chalaza with the hilum. 



Rhizoid (root-formed). Root-like; a name applied to the 

 root-like hairs fomnd in Bryophytes and Pteridophytes. 



Rhizotaxy. Root- arrangement. 



Root-stock. A horizontal, more or less thickened, root-like 

 stem, either on the ground or underground. 



Saprophyte (rotten plant). Organisms that obtain their food 

 from dead or decaying organisms. 



Scalariform (ladder-form). A name applied to ducts with pits 

 horizontally elongated and so placed that the intervening 

 thickening ridges appear like the rounds of a ladder. 



Scale (a flight of steps). Any thin scarious body, as a degen- 

 erated leaf, or flat trichome. 



