CYCADACEAE UPDATED (1999)
 D. J. DE LAUBENFELS

4. SUBGENUS REVOLUTA
Cycas L, subgenus Revoluta de Laub., Blumea 44 (1998) 382.  Type species: C. revoluta Thunb.

Cycas L. section Asiorientales Schuster in Engler, Pflanzenr. 99 (1932) 65.  -- Type: C. revoluta Thunb.

Trunks erect, usually rather short.  Petioles less than 40 cm (usually less than 30 cm), with or without thorns.  Pinnules straight or at least some in the apical part of the leaf curving towards the apex of the leaf, none over 8 mm wide, margins in most species revolute, sometimes extremely so with thickened margins, upper midrib usually in a trough and weak or flat, apex acute or in the narrower examples distinctly rounded.  Apical part of the megasporophyll lacinate, the comb-teeth usually widest in the middle or sometimes all of nearly the same length. 

    Distribution -- Seven species from India to Japan and the Philippines as well as in northern Australia but absent in the equatorial zone. 

    Habitat -- Mostly in restricted almost relictual populations in open forests and savannas of distinctly seasonal areas. 

    Notes -- The narrow and often strongly revolute pinnules with suppressed upper midribs distinguish this subgenus as well as the short petioles and a tendency for the pinnules to curve towards the apex of the leaf in the parts nearer to the leaf apex.  There is a strong tendency throughout subgenus Revoluta for the leaf apex to have several rapidly diminishing pinnules rather than the more usual one reduced pinnule or none, but this character varies from leaf to leaf and is often absent.  In most species in the subgenus the leaves are not flat but rather the two rows of pinnules are raised to form a trough, very much so in some species but variably so and often hardly noticeable.  Short petioles and upward curving pinnules along with pinnule rows forming a trough also characterize several Australian species of subgenus Cycas where hybridization with examples in this subgenus is suspected.  In fact, the two Australian species of subgenus Revoluta, though showing its striking foliage distinctions, have very different reproductive structures, similar to but different than those of subgenus Cycas. 

KEY TO THE SPECIES

22. Cycas revoluta Thunb., Nova Acta Soc. Sci. Upsal. 4 (1783) 40; ex A. Murray in Linnaeus, Syst. Veg., ed. 14 (1784) 926; Smith, Trans. Linn. Soc. 6 (1802) 312, t. 29--30; Schuster in Engler, Pflanzenr. 99 (1932) 81, f. 10L, 11A--B; Pant, Cycas & the Cycadales, ed. 2 (1973) 31, t. 7: f. 6--8; S. H. Fu et al, Flora Rep. Pop. Sin. 7 (1978) 7, t. 1: 1--6; Jones, Cycads of the World (1993) 154, photos pp. 154--155.  -- Type: Thunberg s.n., Japan (holo UPS, photo seen). 

C. inermis Lour., Fl. Cochin. (1790) 632 (in syn.).

Palm-like trees to 3 m, occasionally to 8, trunk diam. 15-- 35 cm, often branched.  Leaves 60--150 cm long including a petiole of 4--10 (14) cm usually with thorns the whole length, pinnule rows bent to form a trough, 100--200 pinnules on each side of the rachis.  Pinnules 6--22 cm x 3--5 mm, margins strongly revolute and thickened, midrib weak and more or less in a trough above, dark green above lighter below.  Cataphyll 9--13 x 0.7--2.5 cm, pungent.  Pollen cone cylindric and tapering towards both ends, 20--70 x 4--8 cm, nearly sessile; microsporophyll 11--17 mm wide, apical part rounded and blunt with  a triangular 3--5 mm beak on the upturned margin.  Megasporophyll with 2--6 ovules; apical part 40--60 x 20--25 mm, triangular to roundish and acuminate, 12--20 comb-teeth along each margin 25--40 mm long, acumen a 50--60 mm spike with a few reduced basal teeth.  Seed 35--39 x 24--28 mm, tomentose, bright orange to red. 

    Distribution -- The Ryukyu Islands of Japan.  Specimens studied: Carow 25, Field & Low 105, Fosberg 37634, 37935, 38117, 38242, Ohwi & Okamoto 994, Savatier 1207, Steere 11, Togashi et al 10074, Walker et al 6033, Wilson 8058. 

    Habitat -- Rocky places, often limestone. 

    Note -- Most closely related to taitungensis which has broader pinnules and a ribbed surface on the stony layer of the seed. 

23. Cycas taitungensis Shen, Hill, Tsou, & Shen, Bot. Bull. Acad. Sci. Sin. 35 (1994) 135, f. 1; Wang et al, Cycads in China (1996) 124, pl. 27.  -- Type: Trou 825, Taiitung, Yenping, Taiwan (holo HAST, not seen).

C. taiwaniana (auct.) non Carruth., Yamamoto, Suppl. Ic. Pl. Form. 4 (1928) 3, f. 2, t. 1--2, 4; Kanehira, Formosa Trees, rev. ed. (1936) 30, t. 9; Li & Keng, Taiwaniana 5 (1954) 27, t. 1; Liu, Ill. Nat. Intro. Lign. Pl. Taiwan 1 (1960) 11. f. 8; Li, Woody Flora Taiwan (1963) 31. f. 1; Flora Taiwan 1 (1975) 496, t. 170; S. H. Fu et al, Flora Rep. Pop. Sin. 7 (1978) 9, t. 2: 1--4; Jones, Cycads of the World (1993) 159, photos pp. 159--60.  -- C. revoluta Thunb. var. taiwaniana (Carruth.) Schuster in Engler, Pflanzenr. 99 (1932) 84, p. p. , quod pl. cult.

Palm-like trees to 5 m high, trunk diam. 25--45 cm, occasionally branched, apex densely tomentose.  Leaves 100--200 cm long including a petiole of 10--30 cm with thorns for most of its length, 110--200 pinnules on each side of the rachis the two rows bent to form a trough.  Pinnules 12--23 cm x 4--8 mm., margins nearly flat to somewhat revolute, midrib weak and more or less in a trough above, dark lustrous green above, lighter below.  Cataphyll 6--12 x 1.5--2.5, pungent.  Pollen cone cylindrical and tapering, 30--55 x 8--10 cm, with a short peduncle; microsporophyll 14--18 mm wide, apical part rounded and blunt with a 1--2.5 mm prickle on the upturned margin.  Megasporophyll with 2--6 ovules; apical part c6 x 3--4 cm, triangular to rounded and acuminate, 12--20 comb-teeth one each margin 25--40 mm long, acumen up to 20 mm long with several reduced basal teeth,  Seed 35--50 x 24--33 mm, tomentose, the stony layer with several longitudinal ribs, orange to bright red. 

    Distribution -- Interior of Taiwan and N. Fujian in China.  Specimens studied: Ching 2260, Merrill 18752, Tanaka 10451, Tsou et al 424. 

    Habitat -- Disturbed areas in forested zones to 950 m. 

    Note -- The tomentose seed, which it shares with revoluta, a broader acumen on the megasporophyll and a smaller pollen cone are about all that differentiate taitungensis from wadei with which it shares the ribbed surface of the stony layer of the seed.      

24. Cycas wadei Merrill, Philipp. Jour. Sci. 60 (1936) Bot., 234; Amoroso, Philipp. Jour. Sci. 115 (1986) 183, f. 1, 20--22, 31--34; Zamora & Co, Guide Philipp. Flora & Fauna 2 (1986) 222, f. 4; Jones, Cycads of the World (1993) 161.  -- Type: Brown s.n., Culion I., Philippines (holo US, iso GH, K, L, NY).

C. hongheensis Yang & Yang in Wang et al, Cycads in China (1996) 62, pl. 9 & f. 4; Yang & Yang, Enceph. 40 (1994) 11, f. 4-5 (nomen).  Type: Yang9301, Yunnan, Gejiu (holo in Herb. Panzhihua Inst. Hort., not seen).

Palm-like trees to 7 m high, trunk with a swollen base to130 cm, 10--20 cm in diam. above the swollen base, often branched.  Leaves 75--132 cm long including a petiole of 20--40 cm with thorns for most of its length, 60--100 pinnules on each side of the rachis the two rows bent to form a trough.  Pinnules 14--22 (26) cm x 5--7 (8) mm, margins nearly flat to slightly bent, midrib weak above and more or less in a trough, dark green above, lighter below.  Cataphyll 3--5 x 1--1.5, pungent.  Pollen cone cylindrical and tapering, 40--70 x 8--12 cm with a c4 cm peduncle; microsporophyll 15--20 mm wide, apical part rounded and blunt with a triangular 5--6 mm acumen.  Megasporophyll  with 2--4 ovules; apical part 50--80 x 25--50 mm, triangular and acuminate to lanceolate, 11--14 comb-teeth along each margin 20--35 mm long, acumen broad and c30 mm long with a few reduced basal teeth.  Seed 32--40 x 25--30 mm, The stony layer with longitudinal ribs, color unknown. 

    Distribution -- Culion and possibly Palawan Islands of the Philippines.  Also apparently in southern China.  Specimens studied: Brown s.n., Herre 1061, Merrill 657, Quisumbing 12163, 15845. 

    Habitat -- In grassy disturbed areas of forested regions. 

25. Cycas immersa Craib, Kew Bull. (1912) 434.  -- Type: Kerr 999, Pang Puai, bet. Lakon & Phre, Thailand (lecto BM, here designated).

C. panzhihuaensis Shou & Yang, Acta Phytotax. Sin. 19 (1981) 335, t. 10: 1--6, 11: 1--10; Zhou, Yang, & Zhou, Mem. N. Y. Bot. Gard. 57 (1990) 150; Jones, Cycads of the World (1993) 150.  -- Type: Yang 10, Dakon Shi, Sichuan (holo HP, photo seen).

C. baguanheensis G. K. & S. Z. Cheng, Acta Phytotax. Sin. 19 (1981) 337, t. 10: 7, 11:11--13; Jones, Cycads of the World (1993) 130.  -- Type: Dakou, Yang, & Wu 13, Baguan He, Sichuan (holo HP, photo seen).

C. pectinata (auct.) non Hamilt., S. H. Fu et al, Flora Rep. Pop. Sin. 7 (1978) 14, t. 4.

C. clivcola subsp. lutea (no Latin description) Tang et al, Cycads of Thailand (1997) 15, figs.

C. nongnoochii (no Latin description) Tang et al., Cycads of Thailand (1997) 20, figs.

Palm-like trees up to 6 m, trunk diam. 15--25 (45) cm, apex densely tomentose.  Leaves 65--160 cm long including a petiole of 18--34 (45) cm with thorns for most of its length, 50--135 pinnules on each side of the rachis the two rows bent slightly to form a trough.  Pinnules 11--23 cm x 5--8 mm, margins slightly bent, midrib weak above and more or less in a trough, dark green above, paler below.  Cataphyll 4--7 x 1--2 cm, pungent.  Pollen cone cylindric and tapering with a 4--6 cm peduncle, 25--50 x 8--11 cm; microsporophyll 20--28 mm wide, apical part blunt to rounded with a 3--12 mm prickle on the upturned edge. Megasporophyll with 2--6 ovules; apical part 30 x 20--30 mm, triangular to rounded and acuminate, 13--23 comb-teeth along each margin 20--40 mm long, acumen up to 6 cm long often with reduced basal teeth.  Seed 25--33 x 20--30 mm, yellow to redd,ish yellow or orange. 

    Distribution -- Northern Thailand and southern China.  Also along the Thai-Cambodia border and possibly in Penninsular Thailand.  Specimens studied: Cavalerie & Fortunat 2001, Hansen et al 31181, Henry 13637, Kerr 999. 5944, Rock 2680. Wang & Peng 2675. 

    Habitat -- Open places in broadleaf evergreen forest and sparce-tree grassland to 2000 m. 

    Notes -- The only species in its subgenus that could be considered of widespread distribution.  The specimen labeled Kerr 999 at K does not correspond to the Kerr 999 at BM and as described by Craib, rather it appears to be a misattributed sheet of Lakshnakara 999, which is siamensis (see this collection at BM). Craib did not specify where his type was deposited.  The specimen at K cannot be considered the type. The outer seed coat (sarcotesta) is frequently shed in this species but this also occurs sporadically in many other species.  Judging from the illustrations, nongnoochii was described from two species, the other being miquelii. 

26. Cycas beddomei Dyer, Trans. Linn. Soc., ser. 2, 2 (1883) 85, t. 17; in Hooker f., Flor. Brit. India 5 (1888) 658; Pant, Cycas & the Cycadales, ed. 2 (1973) 32, f. 9; Rao, Proc. Indian Acad. Sci. B, 79 (1974) 59; Jones, Cycads of the World (1993) 132.  -- C. circinalis L. var. beddomei (Dyer) Schuster in Engler, Pflanzenr. 99 (1932) 67.  -- Type: Yarde s.n., Cuddapah Hills, India (holo K, iso BM -- with the number 7696). 

C. revoluta (auct.) non Thunb., Beddome, For. Man. S. India (1869) 227. 

Palm-like trees to 2 m high, trunk diam. 15--35 cm, often branched.  Leaves 90--120 cm long including a petiole of 10--15 cm with a few upper thorns, at least 100 pinnules on each side of the rachis the two rows bent slightly to form a trough.  Pinnules 9--18 cm x 2--4 mm, margins strongly revolute, upper midrib weak and more or less in a trough, grey-green.  Pollen cone ovate and tapering towards both ends, 22--33 x 7.5--9 cm with a short peduncle; microsporophyll c15 mm wide, apical part acuminate and spreading , the acumen c8--10 mm long with a 10--18 mm terminal subulate spike curving upwards.  Megasporophyll with 2--4 ovules; apical part c40 x 15 mm, lanceolate and acuminate, c9 comb-teeth along each margin 7--15 mm long, acumen a 20--40 mm spike with a few reduced basal teeth.  Seed c40 x 37 mm, yellow. 

    Distribution -- Cuddapah Hills (Madras) on the peninsula of India.  Specimens studied: Gambel 21278, Higgins 16597, Yarde s.n. (7696). 

    Habitat -- Open places in dry deciduous forest. 

    Notes -- Geographically far from related species but bearing clear resemblances to both revoluta of Japan and calcicola of Australia.  The former has differences in the fertile material and color of the pinnules, in the latter the leaves have shorter pinnules and are quite flat (not secund) and there are other minor differences. 

27. Cycas calcicola Maconochie, Jour. Adelaide Bot. Gard. 1 (1978) 175, f. 1; Krempin, Palms & Cycads Around the World (1990) photos p. 20; Jones, Cycads of the World (1993) 135, photo.  -- Type: Maconochie 1314, Katherine, N. Terr., Australia (holo NT, iso K).

Palm-like trees to 3 m high, trunk diam. 17--30 cm, unbranched.  Leaves 60--120 cm long including a petiole of 10--24 (32) cm usually with thorns most of its length, 75--150 (205) pinnules on each side of the rachis the rows not at all bent.  Pinnules 5--14 cm x 2--4 (5) mm, margins strongly revolute, midrib weak above and more or less in a trough, brown pubescent below and sometimes white above, especially when new, dark green, silvery when emerging.  Cataphyll 3--6 x 1 cm, not pungent.  Pollen cone cylindrical and tapering, 17--26 x 5--7 cm, peduncle unknown; microsporophyll c12 mm wide, apical part narrowing sharply to a 6--10 mm beak with the tip sharply curved upwards.  Megasporophyll with 2--6 ovules; apical part 25--30 x 15--20 mm, triangular and acuminate, 13--18 fine papery teeth along each margin 2--4 mm long or entire (see note under normanbyana), acumen a 10--16 mm spine.  Seed 28--35 x 25--30 mm, glaucous, orange. 

    Distribution -- South of Darwin in N. Terr., Australia.  Specimens studied: Dunlop & Byrnes 2156, Lazarides 6624, Maconochie 724, 725, 967, 968, 1303, 1314, 1315, 1317, 1318, 2068, 2069, Must 1076. 

    Habitat -- Deciduous woodland, usually on limestone. 

    Notes -- Distinguished by the short glaucous pinnules, the flat leaves, and the few papery teeth on the megasporophyll. 

28. Cycas cairnsiana Muell., Fragm. Phytogr. Austr. 10 (1876) 63; Krempin, Palms & Cycads Around the World (1990) photo p. 226 (labeled in error pruinosa); Hill, Telopea 5 (1992) 195, f. 11; Jones, Cycads of the World (1993) 134, photo p. 136.  -- Type: Armit in 1876, Newcastle Range, Queensland (holo MEL, iso BM, K).

C. pruinosa Maconochie, Jour. Adelaide Bot. Gard. 1 (1978) 177, f. 2; Krempin, Palms & Cycads Around the World (1990) photo p. 226, lower left; Jones, Cycads of the World (1993) 153, photo.  -- Type: Symon s.n., Teronis Gorge, Durack Ranges, W. Aust., (holo NT, iso K).

Palm-like trees to 5 m high, trunk diam. 12--25 (40) cm.  Leaves 60--110 cm long including a petiole of 4--10 cm with thorns usually for most of its length, 60--140 pinnules on each side of the rachis, distinctly second.  Pinnules 8--20 cm x 2--4 mm, margins strongly revolute, upper midrib weak above and more or less in a trough, dull grey-green and often glaucous.  Cataphyll 7 x 1.5, not pungent.  Pollen cone cylindrical and tapering towards both ends, nearly sessile, 38--50 x 6--9 cm; microsporophyll 12--15 mm wide, apical part narrowing sharply to an 8--24 mm beak spreading with the tip sharply bent upwards.  Megasporophyll with 2--6 ovules; apical part 8--11 cm x 15--25 mm,  lanceolate, 10--15 comb-teeth along each margin 10--25 mm long, acumen a 15--24 mm spike with a few reduced basal teeth.  Seed 35--42 x 30--37 mm, glaucous, color unknown.

    Distribution -- In the Newcastle Range of interior northern Queensland and in the Kimberley region of northern W. Australia..  Specimens studied: Armit in 1876, Maconochie 1127, Symon s.n. 

    Habitat -- In rocky areas among grass and low shrubs. 

    Notes -- The megasporophyll often lacks the lateral teeth (see discussion under normanbyana).  There seems to be no reason to separate cairnsiana and pruinosa whose seeming differences largely stem from very sketchy documentation of the former.

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