Vallecula 



OF BOTANICAL TERMS. 



Vasculum 



constant form. Compare 

 Amorphous. 

 VAIL, see Veil. 



VALLECULA (pi. Vallec'ulae), a 

 groove or furrow, as those 

 between the ridges on the 

 fruit ' of Umbelliferae. Com- 

 pare Sulcus. 

 VALlECULAR CANALS', large 

 intercellular passages, alter- 

 nating with the fibrovascular 

 bundles in the stem of Equi- 

 setum. They are situated in 

 the cortex, and lie between 

 the ridges on the surface. 

 Compare Carinal Canal. 

 VALV'ATE, said of the leaves of 

 a flower in aestivation when 

 they meet at their edges and 

 do not overlap, as the sepals 

 in the rose; valvular. The 

 margins of valvate organs 

 may be rolled or folded in- 

 ward or outward. 

 VALVE, (1) one of the parts of a 

 dehiscent pericarp; (2) the lid 

 of an ascidium or pitcher; 

 (3) one of the halves of a 

 f rustule in diatoms. 

 VALVULAR, see Valvate. 

 VARIABLE, said of a species or 

 other group which embraces 

 many individuals which de- 

 part more or less from the 

 type of the group. The term 

 is applied in a similar way to 

 any organ or character which 

 fails to exhibit uniformity. 

 VARIATION, a transient variety, 

 consisting of but one or a few 

 individuals, less marked than 

 a Sport, and usually but 

 slightly differing from the 

 type of the species or variety 

 to which it belongs. It is sub- 

 ordinate in importance to a 

 Form, and less frequently pro- 

 duced by some peculiar con- 

 dition of the soil or climate. 



VAR'ICOSE, appearing abnor- 

 mally enlarged in places; — 

 applied to hairs and other 

 tubular filaments. 

 VARIEGATED, applied to leaves, 

 etc., which have two or more 

 colors upon the surface, espe- 

 cially to such as are per- 

 manently marked with white 

 or yellow. Compare Bicolor 

 and Chlorosis. 

 VARI'ETY, a group subordinate 

 to a species, founded on char- 

 acters which in cultivated 

 plants are often temporary, 

 and which in the wild state 

 are regarded as permanent, but 

 which gradually merge into 

 those of the main specific 

 form. Compare Species, 

 Race, Sport, and Variation. 

 VARIETY-HYBRID, see Cross. 

 VAR'NlSH, see Blastocolla. 

 VAR'NlSHED, see Vernicose. 

 VA'SA PROPRIA, a term applied 

 by Mohl to the portion of the 

 phloem containing the sieve- 

 tubes and other thin-walled 

 tubular cells. Now seldom 

 used. 

 VAS'CULAR, pertaining to or con- 

 taining vessels. 

 VAS CULARBUN'DLE, see Fibro- 

 vascular Bundle. 

 VAS'CULAR BUN'DLE-SHEATH, 

 a layer of cells between the 

 phloem and cortex, or sur- 

 rounding a fibrovascular bun- 

 dle, or an entire fibrovascular 

 cylinder; phloem-sheath. 

 VASCULAR CYLINDER, see 



Fibrovascular Cylinder. 

 VAS CULAR SYSTEM, see Fibro- 

 vascular System. 

 VAS'CULAR TISSUE, see Vessel. 

 VAS'CULUM, a botanist's collect- 

 ing-case. Formerly this term 

 was applied to an ascidium or 

 pitcher-shaped leaf. 



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