STANDLEY — TREES AND SHRUBS OF MEXICO. 47 



5. CIBOTIUM Kaulf. Berlin, Jahrb. Pharm. 21 : 53. 1820. 

 Reference : Maxon, The American species of Cibotiiim, Contr. U. S. Nat. 

 Herb. 16: 54-58. pi 30-32. 1912. 



Caudex stout, 1 to 8 meters higli, sometimes from its covering of adventitious 

 roots and old stipe bases attaining a diameter of nearly one meter ; fronds 

 erect-arching, the stout stipes and upper caudex clothed with capillary scales 

 as in Dicksonia ; blades ample, of an ovate-deltoid type, bipinnate to tripinnate- 

 pinnatifid, the rachises smooth or nearly so, glabrescent ; pinnae mostly inequi- 

 lateral, the distal pinnules much longer than the proximal ones ; pinnules simi- 

 larly inequilateral, deltoid-oblong to linear, asymmetrical ; under surfaces 

 pruinose to ceraceo-papillate, glabrous, hairy, or rarely subfurfuraceous ; veins 

 oblique, the fertile ones usually simple; sori terminal, essentially marginal; 

 indusium deeply bivalvate, the outer lip consisting of a highly differentiated 

 saccate portion of the leaf margin, the inner of an orbicular to linguiform carti- 

 laginous operculum affixed at its base, somewhat reflexed at maturity. 

 Larger pinnae 40 to 50 cm. long ; sori mostly distant, usually extending out- 

 ward in the plane of the segment, the inner lip of the indusium as large as 



the outer one; leaf tissue chartaceous-membranous 1. C. schiedei. 



Larger pinnae 60 to 80 cm. long; sori contiguous, erect, or the narrower and 

 slightly longer inner lip strongly reflexed at maturity and overlying the 

 costule; leaf ti^siie rigidly herbaceous 2. C. regale. 



1. Cibotium schiedei Schlecht. & Cham. Linnaea 5: 616. 1830. 

 Dicksonia schiedei Baker in Hook. & Baker, Syn. Fil. 50. 1868. 



Humid mountain forests of Oaxa^^a and Veracruz, at 600 to 1,200 meters 

 altitude, the type from Hacienda de la Laguna, Veracruz. 



Caudex 1 meter high or less or (according to Galeotti) attaining a height of 

 4.5 meters; fronds 1.2 to l.S meters long, the blade at least 80 cm. broad, 

 pinnae ascending, deltoid-oblong to deltoid-lanceolate, abruptly acuminate ; 

 pinnules 28 to 30 pairs, pinnatifid nearly to the costa, the larger distal ones 

 11 to 16 cm. long ; segments 25 to 30 pairs, conspicuously pruinose and ceraceo- 

 papillate beneath. 



2. Cibotium reg'ale A'ersch. & Lem. 111. Hort. 15: under pi. 548. 1868. 

 Dicksonia regalis Baker in Hook. &, Baker, Syn. Fil. ed. 2. 461. 1874. 

 Mountains of Chiapas, whence it was introduced into cultivation by Ghies- 



breght. 



Caudex erect, up to 10 meters high, 40 to 50 cm. in diameter, fronds 10 to 12, 

 widely recurved-spreading, up to 4 meters long; blades about 3 meters long, 

 up to 1.5 meters broad ; pinnae mostly spreading, deltoid-lanceolate acuminate ; 

 pinnules about 35 pairs, pinnatifid nearly to the costa ; segments 30 to 35 pairs, 

 conspicuously ceraceo-pruinose beneath. 



3. CYCADACEAE. Cycad Family. 



Reference: A. De Candolle in DC. Prodr. 16': 522-547. 1864. 



Palmlike plants, the leaves pinnate, basal or clustered at the end of a trunk ; 

 flowers dioecious, in large thick cones; seeds nutlike. 



Many of the species are important as food plants because of their edible 

 fruits or of the starch obtained from the stems. They are often grown for 

 ornament. 



Cone scales imbricate in alternate series. Trunk covered by the persistent 

 petioles . 1. DIOON. 



