GLOSSARY OF BOTANICAL TERMS 



25 



specimen is a holotype (q. v.), thus 

 being equivalent to isotype. See 

 also cotype. 





Figure 49. — Achene, or 

 fruit, of the common 

 dandelion (Leontodon 

 taraxacum) : a, Pap- 

 pus ; b, beak ; c, body 

 of the achene 



Parenchyma: Thin-walled, soft cell tis- 

 sue. One of the two primary types 

 of plant tissues, of which the other 

 is termed prosenchyma. Parenchy- 

 ma usually occurs in the form of 

 cubical or polygonal cells ; familiar 

 examples are seen in stem pith, most 

 leaves (except the veins and mid- 

 rib), fruit pulp, etc. 

 Parietal: Literally, of or pertaining to 

 a wall (paries) or wall-like part; 

 hence, wall-borne. Applied specifi- 

 cally, in botany, to 

 a placenta or ovule 

 that is attached to 

 the wall of the 

 ovary. 

 Parted: Not quite di- 

 vided. Said of sim- 

 ple leaves that are 

 incised almost to 

 the midrib or blade 

 base, and so are 

 not quite com- 

 pound. (Fig. 50.) 

 Pathology: The sci- 

 ence which treats 

 of diseased or mor- 

 bid conditions. 

 Plant pathology 

 deals with plant 

 diseases, their 

 causes, effects, and 

 treatment or cure. 

 Pectinate : Comblike ; 

 arranged or di- 

 vided like the teeth of a comb 

 (Latin, pecten). 



Figure 50. — A 

 parted leaf, as 

 in certain spe- 

 cies of oak 



Pedate: Palmately cleft or parted but 

 with the main divisions having a 

 common stalk, i. e., the primary divi- 

 sions twice or more cleft or parted. 

 Thus, the leaves of birdsfoot violet 

 {Viola pedata) and of dragonroot 

 [Ariscema dracontium) are pedate. 

 (Fig. 51.) 



Figure 51. — Pedate leaf, as in (A) 

 birdsfoot violet (Viola pedata) and 

 (B) dragonroot (Ariscema dracontium) 



Pedicel: In an inflorescence consisting 

 of more than one flower, the foot- 

 stalk or stem of an individual flower 

 or fruit. (Fig. 48, d.) 



Pedicellate: Provided with a pedicel, 

 or stalk; not sessile. Said of indi- 

 vidual flowers or florets. 



Peduncle: The stalk of a flower cluster 

 or of an inflorescence consisting of 

 but one flower. See pedicel. 



Pedunculate : Provided with a peduncle. 



Peltate: Shield shaped; a peltate leaf, 

 as in nasturtium, has the petiole at- 

 tached somewhere near the center of 

 the blade. (Fig. 52.) 



Figure 52. — Peltate leaf, as in 

 the common nasturtium 



Pendulous: Hanging down; suspended 

 from above ; pendent ; drooping. 



Pentamerous: Having the parts in fives. 



Pepo: The characteristic indehiscent 

 fruit of the gourd family (Cucurbi- 

 tacese), such as a cucumber, musk- 

 melon, pumpkin, or squash. It dif- 

 fers from a berry chiefly in having 

 a hard, more or less thickened rind 

 (pericarp). 



