134 J- Schuster. — Cycadaceae. 



acuta, peltae strobili § nigrescenti-subfusco- 

 tomentosae, macrosporangia eburneo-albida 7. Z. Ulei. 

 b. Truncus semisubterraneus vel erectus, altus, 



cylindricus. Foliola nervis subtus costato- 



prominentibus, margine integra vel ad apicem 



sinuata vel denticulata. Strobilus $ elongato- 



vel oblongo-cylindricus, pedunculo breviore 



quam strobilus. Microsporophylla peltato- 



cuneata, sub pelta margine utroque fertilia. 



Peltae strobili <$ hexagonae vel pyramidato- 



truncatae, medio subconcavae. Strobilus $ 



cylindricus vel obtusus, breviter pedunculatus. 



Peltae strobili $ altius prismatice productae, 



hexagonae • Subsect. 2. Nervicostatae. 



a. Foliola lanceolata vel ovata, acuminata, 



macrosporangia ovalia, flava 8. Z. Skinneri. 



ß. Foliola longe lanceolata, longe acuminata, 

 utroque microsporophyllorum latere duae 

 series microsporangiorum 9. Z. chigua. 



y. Foliola oblongo-lanceolata, acuminata . . 10. Z. montana. 



d. Foliola lineari-lanceolata, cuspidata, macro- 

 sporangia obovalia, viridi-scarlatina ... 11. Z. pseudoparasitica. 



e. Foliola maxima, amplo-lanceolata, acumi- 

 nata, petiolata, nervorum distantia lata, 

 microsporangia in utroque microsporophylli 



margine 4 — 5 12. Z. Wallisii. 



B. Truncus hypogaeus vel humilis, cylindricus vel 

 tuberosus, simplex vel dichotomus. Folia nervis 

 subtus prominulis vel tenuibus. Strobilus <§ 

 cylindricus vel cylindrico-elongatus, peltae stro- 

 bili <J hexagonae vel quadrato-hexagonae. Stro- 

 bilus § ovoideo-elongatus vel cylindricus. Peltae 

 strobili $ transverse hexagonae Sect. II. Mexicano-meridionales. 



a. Truncus cylindrico-tuberosus, humilis, hypo- 

 gaeus. Foliola obovata, obtusula, ad apicem 

 cartilagineo-denticulato-serrata, margine revo- 

 luto, crasse coriacea, subtus dense furfuracea, 

 superficie pulvere furfuraceo griseo-olivacea, 

 nervis subtus prominentibus. Strobilus <$ 

 cylindricus, breviter pedunculatus. Peltae 

 strobili $ griseo-pubescentes. Microsporo- 

 phylla sub pelta utraque fertilia. Strobilus 5 

 ovoideo-elongatus, breviter pedunculatus. 

 Peltae strobili $ transversim hexagonae, flavi- 

 brunneo-tomentosae Subsect. 1. Furfuraceae. 



13. Z. furfuracea. 



b. Truncus hypogaeus, humilis, cylindricus vel 

 subbulbosus, simplex vel dichotome ramosus. 

 Foliola nervis tenuibus. Strobilus <J cylin- 

 dricus, pedunculo longiore quam strobilus vel 

 vix breviore. Peltae strobili <$ hexagonae, 

 paulo latiores quam longiores. Strobilus $ 



