Revisional Notes on the Morphology and Distribution of <i>Carex filipes</i> var. <i>kuzakaiensis</i> (<i>Cyperaceae</i>)

<p>Carex filipes Franch. & Sav. var. kuzakaiensis (M. Kikuchi) T. Koyama (Cyperaceae) was known as endemic to northeastern Honshu, Japan. Recently, this sedge was recorded in Tochigi Prefecture, central Honshu. Here I add, a new locality of Carex filipes var. kuzakaiensis at the foot of Mt. Keizuru, Oze, Gunma Pref., close to the reported locality in Tochigi Pref. The plants in Hinoemata, Fukushima Pref., the southernmost area of Tohoku district and Okuhida region in Gifu Pref., Central Honshu, which had been identified as C. filipes Franch. & Sav. var. arakiana (Ohwi) Ohwi were also revealed to be var. kuzakaiensis. More than 100 mature tussocks and many seedlings of C. filipes var. kuzakaiensis were found in Oze. Carex filipes var. kuzakaiensis grows on moist ground in summer green forests in the upper montane zone, whereas C. filipes var. arakiana grows in the lower montane zone and hilly-zone. Carex filipes var. kuzakaiensis grows well in disturbed grounds. Morphologically, C. filipes var. kuzakaiensis can be distinguished from var. arakiana in the shorter (< 18 mm long) terminal spike with shorter peduncle and the small (< 5 mm long including a beak) perigynia widest near middle. However, length of peduncle of the terminal spike is sometimes variable. Terminal spikes of C. filipes var. kuzakaiensis are pale green and can be distinguished from var. arakiana which has reddish purple terminal spikes. However, C. filipes var. kuzakaiensis with reddish terminal spikes were also observed in rare cases.</p>