Lygodium

About: Lygodium is a research topic. Over the lifetime, 89 publications have been published within this topic receiving 1408 citations. The topic is also known as: Hagnaya.

Shoot Morphology of the Climbing Fern Lygodium (Schizaeaceae): General Organography, Leaf Initiation, and Branching

Abstract: The leaves of the climbing fern Lygodium are borne on the dorsal surface of a subterranean rhizome and undergo a twining growth to form the aerial portion of the shoot. These leaves have a number of structural and functional analogies to the entire shoot of some twining flowering plants: continuous apical growth, circumnutation, a delay in leaflet expansion below the leaf apex, and budlike resting leaflet apices. The development of the shoot system of L. japonicum (Thunb.) Sw. and L. microphyllum (Cav.) R.Br. was investigated to determine their organographic relationships. The determinate primary leaves and the indeterminate climbing leaves initiate from a single cell on the flank of the apical meristem and are strictly foliar in nature, structurally homologous with each other and with the leaves of other ferns. Dichotomous branching occurs in a manner undocumented for this genus. The shoot of Lygodium is an extreme example of the phenomenon of leaf elaboration common to many ferns. The complex nature of ...

Lygodium Foliage with Intact Sorophores from the Eocene of Wyoming

Abstract: Specimens of Lygodium kaulfussi with attached sorophores and in situ spores from the late Eocene Bridger Formation of Woming are described and compared with similar fossil remains from the early Tertiary of other areas in North America, Europe, South America, and Australia. On the basis of the same criteria emphasized in the taxonomy of extant Lygodium species, the Eocene material from Europe and North America represents a single wide-ranging species that was distinct in some features from the Eocene species known from the Southern Hemisphere. Although not identical with any modern species, L. kaulfussi closely resembles extant L. palmatum of eastern North America in having highly dissected nonlaminar fertile pinnae and psilate spores. Strong dimorphism between the sterile and fertile foliage, as occurs in L. kaulfussi and L. palmatum, was widespread in both the Nothern and Southern Hemispheres in the Eocene and predates the Neogene appearance of the weakly dimorphic foliage characteristic of most extant ...

Identification of antheridiogens in Lygodium circinnatum and Lygodium flexuosum

Abstract: Antheridiogens in two species of Schizaeaceous ferns, Lygodium circinnatum and Lygodium flexuosum, were analyzed by gas chromatography-mass spectrometry. In L. circinnatum, gibberellin A73 (GA73) methyl ester (GA73-Me), which had originally been identified in L. japonicum, was identified as a principal antheridiogen, and the methyl esters of five known GAs (GA9, GA20, GA70, GA88, and 3-epi-GA88) were also identified as minor antheridiogens. In addition, four compounds corresponding to isomers of monohydroxy-GA73-Me were detected. One of these was shown to be 12[beta]-hydroxy-GA73-Me, the parent acid of which has been allocated the GA assignment GA96. The other three compounds, tentatively named X1, X2, and X3, have not been fully characterized. In L. flexuosum, GA73-Me was also identified as a major antheridiogen, with X2 being detected as a minor one. The total antheridium-formation activity in the culture medium of 7-week-old prothallia of L. circinnatum and L. flexuosum was more than 1000 times higher than that of L. japonicum. On the other hand, the response of gametophytes of the former two Lygodium ferns to GA73-Me was more than 100 times lower than that of L. japonicum.

On the control of antheridium formation in the fern species Lygodium japonicum.

Abstract: SummaryIt is demonstrated that prothalli of L. japonicum elaborate, and secrete into the medium, a substance which controls formation of antheridia in this fern species. The antheridium-inducing activity of the medium is stable to boiling for 10 min at both pH 2 and 12. It is adsorbed on charcoal and destroyed by ashing. The results are considered to show that this antheridium-inducing substance differs from the substance which controls the same developmental event in many species of the fern family Polypodiaceae. The results further indicate that the Lygodium factor is also chemically distinct from the substance that controls antheridium formation in A. phyll∗∗∗itidis which, like L. ∗∗∗japonicum, belongs to the fern family Schizaeacea∗∗∗. The individuals that first attain the reproductive phase in a gametophyte population of L. japonicum give rise to one or 2 archegonia before the first antheridium initial appears. This sequence of sex-organ formation is reversed in the prothalli which subsequently attai...

Spread of the Exotic Fern Lygodium microphyllum in Florida

Abstract: Lygodium microphyllum (Cav.) R. Br. (Schizaeaceae) was first reported as an adventive in Florida about a decade ago by Beckner (1968). The plants were known to Beckner from three collections in Martin County near Jonathan Dickinson State Park and a single collection in Palm Beach County from Delray Beach. These climbing ferns should no longer be considered adventive, since they are now naturalized in both these counties. On the fringes of their range, the plants occur mostly in small clumps, while toward the center of the distribution near the Loxahatchee River and Loxahatchee Slough (Fig. 1), Lygodium may cover acres. One colony in Palm Beach County (Sect. 12, T44S, R41W) was one-quarter of a mile long and about 200 yards wide in January 1978. In Florida, the plants are confined to wet, disturbed sites. We have found them only near canals, rivers, ditches, in disturbed swamps, and other sites which have standing water for a large part of the year. We have not determined when the plants were introduced, although the oldest collection we have seen was made in February 1958 (R. A. Long, FLAS). The apparently oldest center of dispersal for L. microphyllum is in the Loxahatchee River area. Large and seemingly old colonies are abundant, suggesting that the plants have been there longer than the past two decades. Another, apparently younger, focal point is in southeastern Palm Beach County. Perhaps the small colony (Fig. 1) was started by the plants being cultivated in nurseries in the 1950's. If, as we have assumed, the ferns first became established in the Lower Loxahatchee River area, how they were dispersed upstream is unknown. Spores might have been spread accidently by birds, since young plants often appear first in small isolated patches on the margins of cypress heads. Two other members of the genus have been reported in Florida, L. japonicum (Thunb.) Swartz and L. palmatum (Berh.) Swartz. The former is an Asian fern naturalized from the Carolinas to Texas (Radford et al., 1968; Correll &Johnston, 1970). An old collection of L. japonicum in Dade County was considered to have escaped on vacant lots, but we suspect that it was only persistent from cultivation. We have not seen recent populations in southern Florida. Lygodium palmatum is considered a native of the eastern United States, ranging from Massachusetts to the Carolinas and Kentucky (Radford, et al., 1968). Although reported in Georgia and Florida (Small, 1938), we have seen no specimens.