GLOSSARY OF BOTANICAL TERMS. 



429 



Ti/rgescehce. — The distension of the cells 

 of plants with sap, producing rigidity or 

 firmness of the tissue. 



Twining-plant. — A plant that climbs by 

 twisting around a support. 



Tylosis. — A protuberance of the wall of a 

 cell through the pit in the wall of an adja- 

 cent duct. 



TyLIGINOSE. — Growing in swampy 

 places. 



Umbel. — That form of indeterminate inflor- 

 escence in which the axis is very short and 

 the pedicels radiate from it like the rays 

 of an umbrella. 



Umbellet, or Umbellule. — One of the 

 secondary umbels of a compound um- 

 bel. 



Umbellate. — Bearing umbels. 



Umbilicate. — With a depression resem- 

 bling that of the navel. 



Umbracultorm. — Shaped like an um- 

 brella. 



Uncate, or uncinate. — Bent into the form 

 of a hook. 



Undate. — (See Undulate). 



Undulate. — Wavy; having a margin that 

 flows gently in and out. Applied to leaves 

 and other flattened organs. 



Unguis. — A claw. 



Unguiculate. — Clawed. Applied to petals 

 that have stalks or claws. 



Uniaxial. — A stem or root is uniaxial when 

 it does not branch. 



Unicellular. — One-celled. Applied to 

 plants that consist of a single cell. 



Uniflorate. — One-flowered. 



Unifoliate. — One-leaved. 



Unifoliolatb. — Applied to a compound 

 leaf that has but one leaflet, as the leaves 

 of the Orange and Lemon. 



Unijugate. — Consisting of one pair. 



Unilateral. — One-sided. 



Unilocular. — Possessing one loculus. 



Unipetalous — One-petaled. 



Uniserial. — Arranged in one series. Ap- 

 plied to parts that are arranged in one 

 horizontal whorl. 



Unisexual. — Possessing but one sex. 



Urceolate. — Urn-shaped. Applied to a 

 gamophyllus calyx or corolla that is shaped 

 somewhat like an urn. 



Uredospore. — One of the spores produced 

 early in the season by the Uredineae or 

 Rusts, and which form rust-like spots on 

 grasses and other plants. 



Utricle — Literally, a little bladder. The 

 name applied to a one-seeded dry fruit 

 with a bladdery, loose pericarp, which 

 either does not dehisce or dehisces irreg- 

 ularly. 



TTACUOLE. — A sap-cavity in the proto- 

 plasm of a cell. 



Vaginate — Sheathed. 



Variolate. — With spots or markings, re- 

 minding one of the pits of small-pox. 



Valvate. — Possessing valves, or opening 

 by valves, as in the dehiscence of some 

 anthers. Also applied to that form of 

 aestivation in which the pieces of the whorl 

 barely touch each other by their edges, 

 but do not overlap. 



Vascular. — Possessing vessels or ducts. 

 The Pteridophyta are often called Vascu- 

 lar Cryptogams. 



Vasifor.m. — Having the form of a vessel. 



Vasiform Elements. — A general term in- 

 cluding tracheids and ducts. 



Vein. — One of the fibro-vascular bundles of 

 a leaf. 



Veinlet. — A small vein. 



Venation. — The veining or system of veins, 

 as that of a leaf. 



Ventral. — Pertaining to the front surface. 

 The ventral aspect of a leaf is that whic 1 

 is usually uppermost or presented to the 

 strongest light; or, in the case of a car- 

 pellary leaf, the inner or ovule-bearing 

 surface. 



Ventricose. — Swollen on one side. 



Vermicular. — Worm-shaped. 



Vernation. — The same as prefoliation. 

 The arrangement of the leaves in the bud. 



Verrucose. — Warty: covered with protu- 

 berances. 



Versatile. — Applied to the anther when in- 

 serted on the slender apex of the filament, 

 in such a manner as to turn readily as on 

 a pivot. 



Verticil. — A whorl, or circle of leaves, all 

 in the same horizontal plane. 



Verticillaster. — A term applied to the 

 pairs of opposite cymes that occur in the 

 axils of the leaves of Mints and at first 

 sight resemble whorls. 



Verticillate. — Whorled ; arranged in 

 whorls. 



Vesicle. — A diminutive air-vessel or 

 bladder. 



Vespertine. — Belonging to the evening. 

 Applied to flowers that open at nightfalL 



