Blechnaceae

K. U. Kramer with the collaboration of T. C. Chambers and E. Hennipman

Blechnaceae (C. Presl) Copeland, Gen. Fil.: 155 (1947). Blechneae C. Presl, Epimel. Bot.: 103 (1851) ["Blechnaceae"]. Stenochlaenaceae Ching, Acta Phytotax. Sin. 16(4): 18 (1978).

Terrestrial or epilithic, occasionally scandent, rarely epiphytic ferns of small to large size. Stem creeping, erect, or scandent, radially dictyostelic, scaly. Petioles aggregated to remote, usually, well-developed, adaxial-ly grooved, with several vascular bundles usually arranged in a U-pattern. Lamina mostly pinnatifid to simply pinnate with entire to pinnatifid pinnae, less frequently simple or lobed, rarely bipinnate. Sterile-fertile leaf dimorphism very widespread and developed to various degrees but by no means univeisal. Veins free or anastomosing, in the latter case (with one exception) without free included veinlets; dissection pattern and/or venation catadromous, at least in the upper part of the lamina. Fertile pinnae/segments with a least one row of costal areoles, their outer arch mostly forming the receptacle of the sori or of one long, continuous sorus, or a special soral vascularization present. Rachis adaxially sulcate, the groove not continuous with those on the pinna costae. Sori short to long and narrow, with few exceptions having an in-dusium that is attached along the receptacle and free towards the costa or costule (this character rarely found in other ferns); occasionally the indusium wanting, the sporangia spreading along the veins or acrosti-choid in arrangement, no sterile appendages borne among the sporangia. Sporangia with strong, triseriate stalk; annulus many-celled, the indurated part extending to the stalk, the several-celled stomium weakly differentiated from the many-celled, non-indurated part of the bow. Spores monolete.

Anatomy and Morphology. Few representatives have so far been studied comprehensively, particularly as to the anatomy of the vegetative organs, the receptacle having received the most attention; e. g., de la Sota and Gouvea Labouriau (1961). Stenochlaena is better known, and its taxonomic position in the present family has partly been established on anatomical grounds (e.g., Mehra and Chopra 1951). The stem is radially dictyostelic, with well-developed, sometimes sclerotic pith. The vascular bundles of the petiole are arranged in a U-pattern, as seen in transection, with the two adaxial bundles larger and the xylem hippocampiform (Fig. 25 F), the number of other bundles, of which there are at least two, dependent upon the size of the leaf (see, e. g., Tardieu-Blot 1932). The stomata are po-locytic with anomocytic ones sometimes also present. In this character Stenochlaena also agrees with the other genera, but its vascular anatomy is more complicated, probably in connection with its growth habit; see under the genus. Young, unfolding leaves are very often tinged with red, a character possibly of taxonomic significance (Tryon and Tryon 1982). Sporangia spreading onto the indusium have been found in Blechnum and Salpichlaena, a very rare feature.

Gametophyte. See especially Stokey and Atkinson (1952a, b), Stone (1962), Atkinson (1973), HolbrookWalker and Lloyd (1973), and Nayar and Kaur (1971). The prothallia are cordate, or elongate when mature, with a distinct, often firm midrib; they often bear simple or few-celled, partly glandular, chlorophyllous hairs. The gametangia are of the common, advanced leptosporangiate type, but antheridia with elongate end cells are known in some species. Gametophytic characters of Stenochlaena again corroborate its placement in the present family.

Karyology and Hybridization. Blechnaceae are one of the cytologically most complex fern families. Probable or certain base numbers found so far are 32 (Doodia), 28-37 but most commonly 28 and 33 (Blechnum), 33 (Brainea, Sadlerta), 34 and 35 (Woodwardia), and 74 (from 377) (Stenochlaena). Tetraploids are frequent in Blechnum (Walker 1966, 1973). Salpichlaena, with n=40, is kept separate from Blechnum partly because of the divergent base number. Some authors tentatively regard x=33 as the basic number in the family (Walker 1973).

A hybrid was reported in Doodia (Parris 1972). The variability of many species in the Blechnum occidentale complex in largely due to hybridization (see especially Walker 1973, Fig. 7; Jenny and Walker 1985, Fig. 43).

Subdivision. As Stenochlaena stands rather apart, subfamilial status seems indicated. The other genera are certainly closely related, and the lines drawn between them are not always satisfactory, possibly being too greatly based on characters such as soral shape, spo-rangial distribution, and venation. When Blechnum, the central genus, has been revised, its borderlines redrawn, and its natural subdivisions determined, the picture is likely to change.

Ecology and Distribution. The family is distributed nearly throughout the world. Blechnum is by far largest genus, with most representatives in the southern hemisphere extending to the mountains of the tropics and relatively few species in the northern hemisphere. Woodwardía is a counterpart of Blechnum, nearly confined to the northern hemisphere, where its distribution pattern is somewhat disjunct and possibly relict. Most of the other genera are Asiatic-Australasiatic-Pacific. Blechnaceae occur in a wide range of habitats, mostly terrestrial, but are rarely found in dry environments. They play an important part in the vegetation of some oceanic archipelagos like Tristan da Cunha, Juan Fernández, and Hawaii.

Affinity. The relationships of the family are not clear. Ideas about affinity with Aspleniaceae, because of superficial resemblance in soral shape, have been refuted by anatomy, karyology, etc. As it is not known whether free or broken sori, free or anastomosing veins, etc. represent a primitive or a derived condition, ties with other families of derived leptosporangiate ferns are difficult to establish. Relationships with Dryopterida-ceae have been suggested but are not very close at best.

Key to the Genera.

1. Sporangia borne on, and (almost) confined to, a longitudinal vein on either side of the costa/costule and parallel to it, rarely spreading onto the indusium, or borne on vein arches flanking the costa/costules; indusium at least initially present 3 Sporangia not confined to such a vein or arch (except in incompletely fertile leaves of Brainea)-, indusium none 2

2, Pinnae articulate (Fig. 25 C; sporaniga with acrostichoid arrangement; stem scandent 9. StenodUaena Pinnae non-articulate; sporangia (in fully fertile leaves) following the veins, eventually often seemingly acrostichoid (Fig. 25 G); stem erect, rather trunk-like 8. Brainea

.1. Veins free, except for the paracostal commissure of fertile leaves bearing the sorus; or a submarginal commissure rarely present; sterile parts without the paracostal commissure 4 Veins anastomosing beside the paracostal commissure or vein arch bearing the sori; or this commissure present in sterile as well as in fertile leaves 5 4. Leaves simple, pinnatifrd, or simply pinnate, or, if bipin-nate (tare), the rachis erect; veins of sterile parts quite free

5. Blechnum

Leaves (at least) bipinnate; rachis twining; veins always joined by a submatginal commissure 6. Salpiehlaena

V Sori mostly long, continuous and parallel to the costules; leaves pinnate+pinnatified or bipinnate; no anastomoses present beside the arches flanking the costules; fertile parts hardly or not contracted 7. Sadleria

- Sori short, discontinuous, or, if long, the fertile parts strongly contracted; veins copiously anastomosing, or, if not, the pinnae undivided 6

6. Lamina deeply pinnatifid to once pinnate, mostly tapering at the base; veins forming 1-3 series of areoles 4. Doodia

- Lamina pinnate+pinnatifid (or almost bipinnate at base) or, if simply pinnate or simple, with very amply anastomosing veins; lamina base various 7

7. Lamina anadromous at base, catadromous above; cross-veins ± arching; outer areoles often with short, free included veinlets 3. Stcenisiobleehnum

- Lamina catadromous throughout (or occasionally pseu-doanadromous or isodromous in places); veins straight, the meshes angular to about hexagonal; free included veinlets none 8

8. Lamina strongly dimorphic; fertile leaves with greatly reduced Iaminal parts; petiole winged to near the base (Queensland) 2. Pteridoblechnum

- Lamina hardly or not dimorphic, or, if strongly so, the petiole unwinged or slightly winged above (northern hemisphere) 1. Woodwardia

Subfamily Blechnoideae

Stem with a simple dictyostele and bearing non-peltate scales; vascular bundles in the petiole forming a simple U in cross-section; sporangia only borne on or near veins.

1. Woodwardia J. E. Smith Fig. 21A

Woodwardia J. E. Smith, Mem. Acad. Turin 5: 411 (1793). Anchistea C.Presl (1851). Lorinseria C. Presl (1851). Chieniopteris Ching (1964).

Terrestrial or epilithic ferns. Stem short-creeping to ascending, or slender and long-creeping, bearing non-clathrate scales. Petiole well-developed, usually stramineous with dark base, often ± scaly, adaxially sul-cate. Lamina pinnatifid, pinnate+pinnatifid, or occasionally simple, not reduced at base, with (subcon-form) terminal pinna or pinnatifid apex, monomor-phic or less often dimorphic, strongly catadromous (or occasionally pseudoanadromous, or isodromous in places); proliferous buds sometimes present in pinna axils or elsewhere. Rachis adaxially grooved, the groove not continuous with those of the costae. Texture herbaceous to subcoriaceous. Margin minutely to coarsely serrate-dentate, with strongly ascending teeth. Veins anastomosing, free included veinlets none; one to many series of areoles present between costa and margin. Free vein ends mostly short, terminating just behind the margin. Sori on paracostal vein arches (giving the impression of an interrupted commissure), flanking the costae and usually also the costules, or in more dissected species only the costules, sometimes embossed. Laminal parts of strongly dimorphic species much reduced in fertile leaves. Spores ellipsoidal,

Doodia Caudata
Fig. 21 A- C. Blechnaceae. A Woodwardia orientalis, part of a segment with venation and son (x7). B Doodia caudata, basal part of pinna with son (x 4). C Doodia aspera, basal part of pinna ( x 4) (A from Ching 1935; B, C from Duncan and Isaac 1986)

surface bearing irregular, more or less connected folds, sometimes echinate or with rod-like elements, the folds often slightly raised.

Thirteen species, very widespread in the northern hemisphere, but with large gaps in the area, south to Costa Rica and western Indonesia, lacking in tropical Africa, the Pacific, and the Antilles. Greatest species concentration in eastern Asia.

2. Pteridoblechnum Hennipman

Pteridoblechnum

Fig. 22. Blechnaceae. Pteridoblechnum neglectum, habit with one sterile and one fertile leaf (x 0.16) (Jones and Clemesha 1976)

Fig. 22

Pteridoblechnum Hennipman, Blumeal3 : 397 (1966); Hennipman (1976).

Medium-sized, terrestrial ferns; stem long-creeping, unbranched, cylindrical, with three vascular strands; scales narrowly triangular, acuminate, non-clathrate, brown, basally attached, sometimes auriculate, irregularly denticulate. Leaves up to a few cm apart, spirally inserted; petiole stout, well-developed, with 5 vascular bundles, brownish, adaxially sulcate in the upper half,

Fig. 22. Blechnaceae. Pteridoblechnum neglectum, habit with one sterile and one fertile leaf (x 0.16) (Jones and Clemesha 1976)

with a lobed wing near its base. Lamina dimorphic, ca-tadromous, deeply pinnatifid, sterile lamina ovate, ± abruptly decurrent onto the petiole, with small lobes between the segments, segments 20-50, linear-lanceolate, coarsely serrate, glabrous, smooth. Venation sage-nioid-reticulate without free included veinlets. Fertile lamina similar but with linear segments, each segment consisting of a costa flanked by two linear, indusiate sori and a vestigial laminal part; indusia opening towards the costa; the wing connecting the segments shortly continuing into their bases. Spores ellipsoidal, bearing prominent, coarse tubercles, especially on their distal face.

A single species, Pt. neglectum (F. M. Bailey) Hennipman, terrestrial in forests, confined to Queensland, Australia.

3. Steenisioblechnum Hennipman

Steenisioblechnum Hennipman, Blumea 30:17 (1984). Pteridoblechnum Hennipmann (1976), p. p., excl. type.

Medium-sized, terrestrial ferns; stem short-creeping, ascending, terete, unbranched; scales narrowly triangular, acuminate, brown with paler edge, entire, auri-culate. Petioles aggregated, spirally arranged, well-developed, stramineous, terete, the upper half adaxially with a median and two lateral grooves. Lamina pinnate, anadromous at base, catadromous above, dimorphic, glabrous except for short, stiff, fuscous, multicellular hairs occurring especially adaxially at pinna insertions. Sterile lamina widest somewhat below the middle, with up to 10 lateral pinnae and a conform terminal one which may be trilobed; pinnae widest somewhat below the middle, the lowest shortly petiol-ulate, the upper ones sessile, base rounded, apex narrowed, margin serrate. Veins anastomosing in an intricate network, about sagenioid near the margin, forming distinct areoles along costae and major lateral veins some of which contain free included veinlets pointing to all sides. Fertile leaves long-petiolate with linear pinnae; indusium hyaline, marginal. Spores ellipsoidal, bearing distant, coarse echinae or cristae.

A single species, S. acuminatum (C. T. White and Goy) Hennipman, terrestrial in forests; like the preceding confined to Queensland.

Doodia R. Brown, Prodr. Fl. Nov. Holl.: 151 (1810); Goy

Small to medium-sized terrestrial ferns; stem short, erect or ascending, sometimes stoloniferous, bearing dark scales. Leaves close, with well-developed petiole, the latter usually dark, adaxially grooved in the upper part, often ± scaly, sometimes pubescent and/or verru-cose. Lamina very deeply pinnatifid to simply pinnate, with few exceptions reduced at base, with pinnatifid or caudiform apex; rachis like the petiole, largely pale, its adaxial groove not continuous with those of the costae. Pinnae sessile or adnate, ovate to linear, herbaceous to coriaceous, mostly glabrous, with percurrent, adaxially sulcate costa; margin sharply serrate-dentate. Venation catadromous or isodromous; veins forked, forming one or a few series of areoles by means of arching cross-veinlets; vein ends at the margin between the teeth. Fertile pinnae sometimes slightly to moderatley contracted. Sori short, on the cross-vein-lets, sometimes somewhat embossed, in one series next lo the costa or also in a second series closer to the margin, the sori of the two series alternating or partly superimposed; indusium membranous, often dark. Spores ellipsoidal, low-rugose or papillate, sometimes nearly plain.

About 12 species, but the taxonomy imperfectly known, several species being quite similar; in Australia, New Zealand, the Pacific Islands east to Hawaii and Easter Island; a few rare species occurring locally in Ceylon, Java, the Lesser Sunda Islands, and New Guinea. Some species are very locally distributed.

This genus seems to be closely related to Woodwardia.

5. Blechnum L Fig. 23

Blechnum L, Spec. Plant. 2:1077 (1753) (for revisional literature see below). Stmthiopteris Scopoli (1760), non Willdenow (1809,

= Matteuccia). Lomaria Willdenow (1809). Blechnidium Moore (1859). Diploblechnum Hayata (1928). Spicantopsis Nakai (1933).

Terrestrial or epilithic, rarely scandent, small to large ferns with creeping or erect, sometimes trunk-like or scandent stem bearing scales that are often dark, long, and narrow. Petiole usually well-developed, sometimes winged to base. Lamina typically pinnatifid or simply pinnate with undivided, long and narrow pinnae, occasionally simple or lobed to pinnatifid, rarely pinnate-!-pinnatifid to bipinnate. Rachis like the petiole, often ± scaly, less often hairy or glandular. Pinnae catadromous, or the lower isodromous or weakly anadromous, often adnate and decurrent (or also surcur-rent), sometimes with small, interspersed lobes, usually non-petiolulate, often firm and glabrous; margin often crenate to sharply dentate. Costa percurrent, adaxially grooved. Veins free, usually forked, with clavate ends terminating just behind the margin, often with hyda-thodes, ending in or between the teeth (if any). Fertile pinnae similar to the sterile, varying to strongly contracted; veins forming a straight, continuous vascular commissure flanking the costa and parallel to and often very close to it, the sporangia being borne there but often strongly spreading at full maturity and covering the fertile pinnae in a seemingly almost acrostichoid manner. The vascular commissure may be on a level different from that to the regular veins, then not being a true commissure; or it may consist of diffuse conducting tissue (see Holttum 1955, Fig. 259, and de la Sota and Gouvea Labouriau 1961); in species with much reduced fertile laminal parts the commissure may seem to be marginal. Indusium long and often narrow, initially covering the sporangia, eventually sometimes fugacious or hidden by the sporangia, in strongly dimorphic species often seemingly marginal. Sporangia inserted on the commissure but sometimes spreading onto the indusium. Spores ellpisoidal, surface very variable: slightly papillate to nearly smooth; rugose or with wing-like folds; coarsely echinate to

Blechnaceae Colombia
Fig. 23 A, B. Blechnaceae. A,B Blechnum penna-marina. A Plant with sterile and fertile leaves (x 0.6). B Detail of fertile leaf (x 3) (Looser 1958)

reticulate, the reticulate elements sometimes thin; rarely with spheroidal deposit.

Characters of Rare Occurrence. Pinnate+pinnat-ifid, or even bipinnatifid leaves in the East Asiatic B.fraseri (Cunn.) Luerssen and a "variety" of the Madagascan B. microbasis (Baker) C. Chr. Venation as in Doodia, also in sterile leaves, but with long son of Blechnum type, in a few species like the Asiatic B. ("Blechnidium") melanopus Hooker and the South American B. heringeri Brade; di- or trimorphic sterile leaves in a few species like B.filiforme (A. Cunn.) Et-

tingsh. from New Zealand which also diverges by having a slender, high-climbing stem; broken sori and sori at an angle to the costa in forms of the African B. punctulatum Sw.; articulate pinnae in B. serrulatum L. C. Rich, of tropical America and Australasia.

A subcosmopolitan genus of an estimated 150-200 species, taxonomically very incompletely known; modern revisions exist only for a few species groups, more for some limited areas (e.g., Looser 1947, 1958; Copeland 1950; Schelpe 1952; Brownlie 1969; A. R. Smith 1985, etc.). The genus is poorly and only locally represented in north-temperate regions, very richly in south-temperate regions, in tropical-montane to subalpine areas, and on oceanic islands; e. g., New Caledonia has 16 species, New Zealand 15, Venzuela 24, Chile 11, etc. There are few species in continental Africa. Many species grow in forests and thickets, often by streams, other in open places.

A natural subdivision of the genus has not been given. Sterile-fertile dimorphism has been much used in the past, also for splitting off parts of the genus ("Lomaría", "Struthiopteris"), but this does not bring together natural alliances. Natural entities, as species groups, have been described for the Neotropics by Tryon and Tryon (1982).

It is not advisable to exclude species that diverge only in certain single aberrant characters, as indicated above.

Strongly dimorphic species have in the past been confused with Plagiogyria. The latter genus is easily recognized by the complete absence of scales and by its adaxially non-sulcate costae.

6. Salpichlaena Hooker

Salpichlaena Hooker in Hooker and Bauer, Gen. Fil.: pi.93

Very large terrestrial ferns with long-creeping stem bearing small, rigid, dark (or pale-edged) scales. Leaves remote; petiole long, stout, stramineous to tan, adaxially sulcate. Lamina to several m long, with twining, stramineous, smooth or lightly pubescent, adaxially sulcate rachis bearing numerous subopposite, large primary pinnae, these long-stalked and with long ra-chidule, the adaxial groove of the latter evanescing towards the stalk. Pinnae pinnate or rarely bipinnate at base, with several, usually subopposite, relatively long-stalked pinnules, the basal rarely trifoliolate. Pinnules chartaceous-subcoriaceous, narrowly oblong to linear, entire, acuminate-cuspidate, with rounded base, the upper sessile but scarcely reduced and not confluent, a conform terminal pinnule present. Costa percurrent, adaxially sulcate; veins close, numerous, evident, simple or basally forked, straight almost to their tips, joined there by an intramarginal commissure just be

Nicaragua Single

Fig. 24. Blechnaceae. Sadleria pallida, abaxial side of fertile lamina; cult. Berkeley, California. Phot. K. U. Kramer hind the pale-sclerotic margin. A few tan scales sometimes present on axes and costae beneath. Usually the lower pinnules anadromous, the upper catadromous in venation. Fertile pinnules weakly to strongly contracted, sometimes almost lamina-less, narrowly oblong to linear; son linear, continuous, paracostal, on a continuous vein runnig parallel to the costa and flanking it on either side, the sporangia confined to this vein or sometimes spreading to the indusium. Indusium very long and narrow, continuous, initially completely covering the sporangia, the edges of two opposite ones meeting over the costa; no sterile organs among the sporangia. Spores monolete, ellipsoidal, faintly papillate-rugose.

A single species, S. volubilis (Kaulf.) Hooker, widespread in tropical America, from Nicaragua and the Lesser Antilles to Bolivia and SE Brazil. Scandent in trees and shrubs, in forests and thickets, at lower to higher elevation.

Forms with varying degrees of contraction of fertile pinnules do not merit taxonomic recognition.

  1. 24. Blechnaceae. Sadleria pallida, abaxial side of fertile lamina; cult. Berkeley, California. Phot. K. U. Kramer
  2. Sadleria Kaulfuss

Fig. 24

Medium-sized to large terrestrial ferns, often growing on lava. Stem erect, often trunk-like with age, bearing entire, non-clathrate, brown scales. Leaves borne in a rosette; petiole stramineous or less often dark, mostly stout, adaxially sulcate, bearing very long, narrow, partly filiform, light brown scales, especially at base. Lamina pinnate+pinnatifid or bipinnate; rachis like the petiole, stramineous, often ± scaly, adaxially with at least one groove which ist not continuous with the grooves on rachidules and/or costae. Texture of lamina firm; upper pinnae, pinnules, etc. gradually reduced and confluent; basal pinnae somewhat shortened. Pinnae sessile, catadromous (or isodromous); basal segments sometimes springing from rachis rather than from rachidule. Segments numerous, ovate to tongue-shaped, mostly adnate, connected or free, sub-entire to crenate, the upper confluent; surfaces glabrous or scaly beneath. Costae evident; veins forked, free but joined by costal arches whether sterile or fer

Blechnoid Fertile Vein
  1. 25A-G. Blechnaceae. A-E Stenochlaena palustris. A Parts of sterile and fertile lamina (x 0.25). B Tip of sterile pinna with venation (x 1). C Insertion of sterile pinna on ra-chis (x 2.5). D Transection of fertile pinna ( x 5). E Peltate scale of stem ( x 20). F, G Brainea insignis. F Transection of petiole ( x 12.5). G Base and apex of pinna showing arrangement of sporangia and venation ( x 1.3) (A-D from Holttum 1955; E,F from Tardieu-Blot 1932; G from Flora Taiwan 1975)
  2. 25A-G. Blechnaceae. A-E Stenochlaena palustris. A Parts of sterile and fertile lamina (x 0.25). B Tip of sterile pinna with venation (x 1). C Insertion of sterile pinna on ra-chis (x 2.5). D Transection of fertile pinna ( x 5). E Peltate scale of stem ( x 20). F, G Brainea insignis. F Transection of petiole ( x 12.5). G Base and apex of pinna showing arrangement of sporangia and venation ( x 1.3) (A-D from Holttum 1955; E,F from Tardieu-Blot 1932; G from Flora Taiwan 1975)
  3. Sori as in Blechnum but mostly shorter, slightly embossed. Spores distinctive for the species (Lloyd 1976), ellipsoidal, bearing small, irregular sheaths, these usually more or less eroded and exposing the lower reticulate formation.

Probably four species; the only fern genus restricted to Hawaii. Some species are pioneers on lava (see, e.g., Holbrook-Walker and Lloyd 1973). Very closely related to Blechnum and perhaps only infragenerically distinct.

8. Brainea J. Smith Fig. 25

Rather large terrestrial ferns with erect, ± trunk-like stem bearing an apical rosette of leaves; apex bearing long, narrow, entire, centrally dark-banded scales. Petiole well-developed, stramineous, adaxially unisul-cate. Lamina medium-sized to large, firm, simply pinnate (very rarely bipinnate at base), with numerous sessile, linear pinnae, the lower somewhat reduced, the upper gradually reduced and confluent; rachis like the petiole, scaly or glabrescent, its adaxial groove not continuous with those of the costae. Costa evident, percurrent, scaly or glabrescent beneath; veins forked, parallel, free except for the basal parts which are connected by a series of short paracostal arches in both sterile and fertile leaves. Venation catadromous. Margin crenate, ±revolute. Sparingly fertile pinnae with naked sporangia borne on the vein arches; fully fertile pinnae somewhat contracted, bearing the sporangia along most of the length of the veins, almost entirely covered by them at full maturity. Spores ellipsoidal, irregularly low-rugose to nearly plaia

A single species, B. insignis (Hooker) J. Smith, growing in open places and thickets, distributed from

NE India, S. China, and Taiwan to Sumatra and Malaya. Closely related to Blechnum, differing in venation, sporangial disposition, and lack of an indusium.

Subfamily Stenochlaenoideae

Stem long-scandent, dictyostelic, with a few larger, central and many smaller, peripheral vascular bundles, bearing peltate scales. Vascular bundles of the petiole with many vascular bundles in two circles; sporangia with acrostichoid disposition.

Monogeneric.

9. Stenochlaena J. Smith Fig. 25 A- E

Stenochlaena J.Smith, Hooker's J. Bot. 3: 401 (1841); Holt-

turn (1932,1971).

Stem veiy long-creeping or scandent, the outer bundles of the dictyostele roughly arranged in 2 or 3 concentric circles; surface of stem green, sparsely beset with small, peltate, round to narrow scales, eventually glabrescent except for the apex. Leaves remote; petioles non-articulate, glabrous or slightly hairy, well-developed, adaxially narrowly sulcate and with some additional ridges and grooves, with a continuous lateral aerating line that extends onto the stem. Lamina strongly dimorphic. Sterile lamina simply pinnate with an odd, conform terminal pinna; rachis like the petiole; pinnae usually alternate, (sub)sessile, ± distinctly articulate at base except for the terminal pinna, oblong-lanceolate with unequal base, not lobed, margin sharply toothed, lower surface sometimes short-hairy; costa percurrent, adaxially shallowly grooved, the groove evanescent at base. Veins close, parallel, simple or forked, ending at the sclerotic margin in (and between) the teeth, free except for a series of long, very narrow, inconspicuous costal areoles; venation anadromous at base of lamina, in the upper pinnae ± distinctly catadromous; anterior base of pinnae with a callose gland, similar glands often present on rudimentary, deciduous pinnae below the normal ones. Fertile lamina once (or in one species twice) pinnate, with very narrow, articulate pinnae, these beneath covered by the sporangia except for a narrow sterile marginal band; venation similar to that of the sterile pinnae, the commissure more evident. Sterile organs among the sporangia wanting. Spores ellipsoidal, bearing distant tubercles, mostly on distal face, or these sometimes fused in parallel rows.

Six species (Holttum 1971) in tropical and warm-temperate parts of the Old World, two in Africa (to South Africa) and Madagascar, the others from India to NE Australia, east to Tonga and Samoa. Formerly credited with a pantropic distribution and many more species, due to confusion with the genera Teratophyl-

lum and Lomariopsis, here placed in Lomariopsida-ceae. Holttum (1932) was the first to elucidate this confusion.

Somewhat divergent from the other genera of Blech-naceae, mainly in anatomical characters; but venation, stomata, spores, and gametophyte agree best with this family. If the base number would be shown to be really x-=37, this would constitute another confirmation.

The ontogeny of the venation was studied by Leist (1975).

Selected Bibliography

Blasdell, R. F. 1956. A comparative study of Hawaiian species of the fern genus Doodia. Bull. Torrey Bot. Club 83: 62-71.

Brownlie, G. 1969. Flore de la Nouvelle-Calédonie et Dépendances. 3. Ptéridophytes. Paris: Museum National d'Histoire Naturelle.

Ching, R. C. 1978. The Chinese fern families and genera, etc. Acta Phytotax. Sin. 16:1-37.

Copeland, E. B. 1950. Aspleniaceae and Blechnaceae of New Guinea. Philipp. J. Sei. 78: 207-229.

Goy, D.A. 1939. The rasp fern (Doodia) of Australia. Queensl. Natural. 11: 23-38.

Hennipman, E. 1966. Pteridoblechnum, a new genus of Blech-noid ferns from Australia. Blumea 13: 397-403.

Hennipman, E. 1976. A second species of Pteridoblechnum (Blechnaceae) formerly referred to Leptochilus acuminatus C.T. White and Goy. Proc. R. Soc. Queensl. 87: 95-98.

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