Systematics Of Peranemaceae From China

Peranemaceae is a new family suggested by Ching Ren-Chang in 1940,but it was incorporated into the Woodsiaceae in 1954 and established formally in 1978,including 3 genus:Peranema D.Don,Diacalpe Bl.,Acrophorus Presl,about 20 specices,14 species of them are from China.Peranemaceae is the style of shade-tolerant tropical ferns,medium body, the shape of sporangium is orbicular,and born of the back or the top of the small vein, without handles or has long handles;the style of indusiums is under-cover;the style of sporangiums is wall fern;the style of spore is oval;The basic number of the chromosome is 41.The systematic position of the Peranemaceae is controversial all along.It was incorporated into the Aspidiaceae with Woodsiaceae by Copeland;Hotttum put them into the Dryopteridoidaae of the Dennstaedtiaceae;Kramer and Kato put them into the Athyrioideae of the Dryopteriaceae s.l.Pichi-Sermolii's system is consisitent with Ching Ren-Chang(1978),he consider each of them as the absolute family.Based on the current view of molecular systematics(Wang Ma-li,2008),believe that the Peranemaceae and the Woodsiaceae have the distant relationships,the Peranemaceae is close to the Dryopteriaceae s.l..The Woodsiaceae and Peranemaceae are the plants that in different evolutionary route,The systems that Ching Ren-Chang(1978) and Pichi-Sermolii(1977) considered them as the independent families are suitable.The Nothoperanema(Tagawa) Ching is a small genus of Dryopteriaceae s.l.,it have 5 species now,the squama,the shape and texture of leaves,and many extermal forms are close to the Peranemaceae,the two may have close relationships.The Lithostegia Ching is a individual specie genus,L.foeniculaceae(Hook.) Ching was considered as the member of Peranemaceae,belong to the Peranema Don or Diacalpe Bl., and it was incorporated to the Dryopteriaceae s.l.by R C Ching in 1965.Many features of Peranemaceae,Nothoperanema(Tagawa) Ching and Lithostegia Ching were described in this paper,including the leaf epidermal,tracheary elements,spore morphology,scales,in order to determine the reasonable systematic position of the Peranemaceae.1.Leaf epidermisBy comp ration with three aspects of the features of up epidermal,stomatal styles,the stomatal density.In Peranemaceae and Nothoperanema(Tagawa) Ching,the pattern of anticlinal walls of the up epidermal is mostly irregular concave convex or sinuolate,the most of cell's shape is long,the main style of stomatal is coaxillocytic or axillocytic,polocytic and copolicytic are lesser,both Peranemaceae and Nothoperanema(Tagawa) Ching have a small quantity of anomoteracytic and anomocytic.Besides these,pericytic appear in Peranemaceae, desmocytic appear in Nothoperanema(Tagawa) Ching The stomatal density of Peranemaceae is 4.1～2.2pieces/mm~2,Nothoperanema(Tagawa) Ching is 8.5～14.8 pieces/mm~2.The pattern of anticlinal walls of up epidermal of Lithostegia Ching is vertical,the shape of the cell is long,Anomoteracytic and brachyparacytic are main pattern of the styles of stomatal,the stomatal density is 4.7pieces/mm~2.The features of up epidermal of Peranemaceae are close to the Nothoperanema(Tagawa) Ching,2.Tracheary elementsTracheary elements of 10 species of Peranemaceae and 3 species of Nothoperanema (Tagawa) Ching and 1 species of Lithostegia Ching from China were examined by scanning electron microscopy(SEM).The results indicate that the end walls have the same morphological characteristics and structure as the lateral walls.The lateral walls have perforation plates.The tracheary elements could also be divided into 4 types:(1) scalariform without dimorphic width perforation;(2) scalariform with perforation pit dimorphism;(3) reticulate-scalariform plates;(4) coarse-pored perforation plates.According to the extent of remnants of pit membrane,Nothoperanema(Tagawa) Ching is close to the Peranemaceae hardly,both of them have 3 styles:some region have intact pit membrane,web like or threadlike,a little or without.The features of tracheary elements indicate that Peranemaceae and Nothoperanema(Tagawa) Ching have close connection.The Lithostegia Ching was considered as a member of Peranemaceae for a long time, according to the research,we found that it has the typical scalariform perforation plates,no associated or crossed phenomena,and some region have intact plate,no dimorphic phenomena,no weblike or threadlike remnants,these suggest that The Lithostegia Ching is in a primal evolutional position.We speculate that Peranemaceae is evaluative then the Lithostegia Ching,the most of species have the relatively evolutional styles of perforation plates,and the remnants of pit membrane is less then The Lithostegia Ching,it suggest that there is a rationality that putting Lithostegia Ching out from Peranemaceae.Different from the traditional ideas,we conclude that the tracheary elements which have perforation plates only on end walls are vessel elements,tracheids have end walls and lateral walls with the same morphological characteristics or structure,with perforation plates or not. The tracheary elements in ferns are tracheids.The feature of tracheary elements indicate that: the Peranemaceae is a member of the Dryopteridaceae group,but not a original one,which may be a evolutionary member.The Peranemaceae and the Dryopteridaceae have many similar features,but there are still a lot of differences between them.So it is reasonable to consider the Peranemaceae as an independent family.Acrophorus Presl might be more advanced,Peranema D.Don might occupy a primitive position relatively,and the systematic position of Diacalpe B1 might be between Acrophorus Presl and Peranema D.Don.3.SporeThe Peranemaceae,Nothoperanema(Tagawa) Ching and Lithostegia Ching share the same exterior morphology of spore,the spore is ellipse from polar sight and bean shape from equator sight The surface omamentation of perinea of Peranemacea have drapes or prominencies,the Nothoperanema(Tagawa) Ching have verrucous prominences too.And the size of them are close to each other,the size of Peranemaceae range from(24～32.6) um to (36.9～48.6) um,the size of Nothoperanema(Tagawa) Ching range from(18.1～32.5) um to (29.9～42.4) um.,different from the former two,the spore of Lithostegia Ching have lophate prominency,with broad wings,the size is 43.2×50.5um.4.Morphology and anatomy researchBy comparison with rhizome,insertion manners of lamina,the shapes of leaves, ornamentation of perispore and the shape of indusium of Peranemaceae and Nothoperanema (Tagawa) Ching,we find that there is a resemblity between them,and they have the intimate connection.The Lithostegia Ching is different from them hardly.According to inspection on scale of rhizome,the scale of Peranemaceae,Nothoperanema (Tagawa) Ching and Lithostegia Ching are lanceolate,with long shuttled lumina.The margin of scales of most species of Peranemaceae and Nothoperanema(Tagawa) Ching are smooth,a few of species has hair and glandular hair,the margin of scales of Lithostegia Ching has small teeth.Based on the above-mentioned,Peranemaceae and Nothoperanema(Tagawa) Ching have nearer connection,but the differences are exist,Peranemaceae and Lithostegia Ching have the distinct relationship.The Peranemaceae is a member of the Dryopteridaceae group,but not a original one,which a evolutionary member.So it is reasonable to consider it as an independent family.