GLOSSARY. 181 



Palet (chaff). In grasses, the inner bract of the flower. 



Palisade cells. The elongated parenchyma cells of a leaf, which 

 stand at right angles to its surface, and are often con- 

 fined to the upper part. 



Palmate (pertaining to the hand.) Radiating like the fingers; 

 said of the veins or divisions of some leaves. 



Panicle (a tuft). A loose and irregularly branching flower- 

 cluster, as in many grasses. 



Pappus (down). The modified calyx of the Composites. 



Paraphysis, pi. paraphyses (accompanying organs). Sterile 

 bodies, usually hairs, which are found mingled with the 

 reproductive organs of various Cryptogams. 



Parasite. An organism that obtains its food from other living 

 organisms. 



Parenchyma (that which pours in beside). Ordinary or typical 

 cellular tissue, i.e., of thin- walled, nearly isodiametric cells. 



Parthenogenesis (virgin generation). The formation, without 

 fertilization, of a spore which is functionally the same as 

 a sexual spore. In general it means that the female 

 gamete becomes a spore directly. 



Pedicel (a little foot). The stalk upon which an organ is 

 borne. 



Peduncle (a little foot). The flower-stalk. 



Pentacyclic (five cycles). Applied to flowers whose four kinds 

 of floral organs are in five cycles. 



Perianth (around the flower). The floral envelopes, or leaves 

 of a flower, taken collectively; and an analogous envelope 

 of the sporogonium of certain liverworts. 



Periblem (a cloak). A name given to that part of the meri- 

 stem at the growing point of the plant-axis, which lies 

 just beneath the epidermis and develops into the cortex. 



Pericambium (surrounding growing tissue). In roots, the 

 external layer of the fibro-vascular cvlinder. 



Perichaetium, pi. perichatia (surrounding hairs or leaves). In 

 Bryophytes, the leaves or leaf-like parts which envelop the 

 clusters of sex-organs, forming in some cases the so-called 

 flower. 



Perigynous (around the ovary). Applied to those flowers 

 whose parts arise from around the wall of the ovary. 



Peristome (around the mouth). In mosses, usually bristle- 

 like or tooth-like structures surrounding the orifice of the 

 capsule. 



