Numerical Taxonomic Study in Annual Cyperaceous Weeds

Three species of Cyperaceous weeds, Cyperus iria (12 strains), C.　microiria(12 strains) and C. amuricus (6 strains), were collected from different sites of Okayama, Tottori and Tokyo prefectures, and various morphological characters, biomass and seed production were observed on the plants which were cultivated at Kurashiki. The analysis of variance showed a significant difference among the strains in each character. However, the species overlapped with each other in most morphological characters. Prinipal component analysis on the 21 characters showed that 83% of the total variation could be explained by the first three components: the first component (37%) was regarded as factors concerning spikelet and seed production; the second component (28%) was regarded as factors concerned the size of vegetative parts; the third component (18%) was largely affected by seed weight and floret density. Scatter diagram on the first and third principal components showed that the 30 strains of three species divided into three groups, and strains in each group correspond to the three species without exception. Based on the second and third principal components, strains of C. microiria were further divided into three sub-groups according to size of vegetative parts. Using the cluster analysis, 30 strains of these species were divided into four large clusters; the first was composed of C. amuricus strains, the second was of three strains of C. microiria, the third included the remaining strains of C. microiria, and the last cluster was composed of C. iria strains. It may be concluded that C. microiria is composed of two or three ecotypes which are different in morphological and reproductive traits.

カヤツリグサ科の3種の雑草カヤツリグサ（C.microiria Steud.）12系統、コゴメガヤツリ（Cyperus iria L.）12系統およびチャガヤツリ（C.amuricus Maxim.）6系統を岡山県、鳥取県および東京都なら採集して倉敷で栽培し、形態的特性、バイオマスおよび種子生産性など21形質を調査した。各形質を分散分析したところ系統間差はいずれも有意であったが、種間の値は多くの形質で重複し、単一形質による種の判別は困難であった。21形質間の相関行列を主成分分析したところ、上位3主成分の累積寄与率は83％と大きく、第1主成分（37％）は小穂の形態と種子生産性、第2主成分（28％）は生長量、第3主成分（18％）は種子重と小穂密度とそれぞれ関係が深いとみられた。第1主成分と第3主成分によって供試30系統は3群に分けられ、各群はそれぞれの種と一致した。さらに、第2主成分と第3主成分によってカヤツリグサ種内の系統は主として生長量の異なる3群に分類できた。クラスター分析によって供試30系統は4つの大きな群に分けられた。一番目の群には、C.amuricusの全系統、二番目の群にはC.microiriaの3系統、三番目の群にはC.microiriaの残りの系統、および最後のクラスターにはC.iriaの全系統が含まれた。従って、C.microiriaha形態的および生態的形質において異なる2ないし3の生態型から成ると考えられた。このように数量分類学あるいは多変量解析はカヤツリグサ科の雑草の種間ならびに種内の分類に極めて有効な解析法であることが示された。