Temperature influences Kyllinga brevifolia and K-squamulata growth

Kyllinga species are becoming more common throughout the southeastern Unite d States. Two species, Kyllinga brevifolia and Kyllinga squamulata, in part icular are prevalent weeds in turfgrass. To better understand these weeds, growth chamber studies determined the growth of K. brevifolia, K. squamulat a, and Cynodon dactylon X Cynodon transvaalensis as influenced by three tem perature regimes (33/24, 25/17, 13/11 C day/night, respectively). Temperatu re influenced almost all aspects of Kyllinga species growth. Plant height o f both Kyllinga species increased nearly twofold after 8 wk at high tempera tures. Plants were mowed each week to 2.5 cm; both species produced more th an twice as many clippings by 8 wk at high (33/24 C) temperatures than at l ow (19/11 C) temperatures. Destructive analysis at 8 wk revealed that K. br evifolia sheet and root weight increased with decreasing temperature, where as K. squamulata shoot and root weights were not affected by temperature. S hoot weight percentage for both Kyllinga species increased from 59% in medi um temperatures to 69% in high temperatures. K. brevifolia shoot weight per centage decreased to 53% in low temperatures, whereas K. squamulata shoot w eight percentage increased to 72%. K. brevifolia inflorescences formed at 2 , 3, and 5 wk in high, medium, and low temperatures, respectively whereas K . squamulata flowered immediately in all temperatures. C. dactylon X C. tra nsvaalensis and Kyllinga species growth were similar within each temperatur e regime throughout the 8-wk study.