120 



KEY TO THE FAMILIES AND GENERA 



178. GNETACE^ffi. 



I.«afles9 shrubs with joinfcd lirnnchos and settles 



opposite the nodes connate into n httlc sheath. . bphedra. 



The verj' curious genus Welnilschin may be found in botanical 

 collections. 



179. TAXACE.ffi. 



A. Anthers 2-«lled: tropical or subtropical trees 

 and shrubs. 

 B. Scales of pistillate ainents few, adnate to 

 peduncle and with it usually fleshy: Ivs. 



linear to ovate, rarely scale-like 1. Podocarpus. 



BB. Scales of pistillate anicnts short, broad and 

 somewhat fleshy, imbricate: Ivs. mmute 

 and scale-like: branchlets flattened and 



If .(jiip 2. Phylloc- 



AA. Anthers 3-S-ceiled: Ivs. Unear;hardy or nearly \ladus. 



hardy trees and shrubs. 

 B. Pistillate fls. consistinn of several decussate 

 2-ovuled carpicles: Ivs. with 2 glaucous 

 lines below broader than the 3 green 

 lines 3. CepAao- 

 BB. Pistillatefls. reduced to 1 o\Tlle. [taius. 

 c. Carpicles at maturity inclosing the seed 

 and adnate to it: anthers 4-celled, cells 

 free: Ivs. with 2 glaucous lines below 



narrower than the green lines . 4. Toireya. 



cc. Carpicles at maturity partly mclosmg the 

 seed, not adnate to it: anthers 6-8- 

 celled. cells connate: Ivs. pale green 

 below 5- r«^«- 



180. PINACE.ffi. 



A. Lvs. spirally arranged. 



B. Carpicles simple; o\'ule 1, reversed; 



cone-scales with 1 seed 1. Abaucabia Tbibb. 



BB. Carpicles divided into scale and 

 bract, sometimes connate. 

 c. 0\-ules 2, reversed; scale and bract 

 always distinct; cone-scales with 



2 usually winged seeds 2. Abies Thibe. 



cc. 0\-ules 2-8, axillary and upright or 

 on the scale and at least finally 

 reversed; cone-scales with 2-8 



ggeda 3. Taxodicm Teibe. 



AA. Lvs. opposite or whorled, often scale- 



like: ovules upright 4. Cdprebscs Tbibe. 



1. Araucaria Tribe. 



A. Seeds free from the scale, with 1 or 2 wiiigs: 

 lvs. broad, generally elliptic, more or less 



distichous and rather remote ■ • 1- Agathu. 



AA. Seeds adnate to the winged or wing ess scale: 

 lvs. large, scale-like or needle-shaped, 

 spirally arranged, crowded 2. Araucana. 



2. Abies Tribe. 



A. Foliage deciduoas, partly fascicled. 



B. Male flu. solitary in a leafless scaly bud; con- 

 nective not produced beyond anther-cellfl 

 nor scarcely prominent: cones reflexed; 



scales persistent. 



3. Larix. 



BB. Male fls. clustered, pendulotis: cone-scales 



deciduous ■*. Pseudolarix. 



„ FoUage evergreen. . 



B. Connective of anthers usually produced mto 

 a scale-like appendage. 

 c. Male fls. subspicate at ba.se of new shoots: 

 cone-scales persistent: lvs. in clusters of 



2-5, rarely solitary 5. Pmus. 



cc. Male fls. solitary in the cluster of lvs. 

 which terminate short branchlets: cone- 

 scales finally deciduous: lvs. partly fas- 



cicled aa in the larch 6. Cedrus. 



CCC. Male fla. solitary in the aidls: cones 

 reflexed; scales persistent: lvs. solitary, 

 4-angled or flattened and glaucous 



above, green on the back 7. Picea. 



BB. Connective of anthers simply umbonate 



beyond the cells or hardly prominent; 



male fls. solitary in axils: lvs. sohtary, 



lumally flattened, glaucous or paler below. 



C. Cones reflexed ; scales persistent. 



V. Hubtending bract conspicuous »• Paeudotauga. 



DD. Subtending bract small 9- Tauya. 



CC. Conea erect. 



D. Scales peri-stcnt; sendu about an long a« 

 scales; bracts much shorter than 

 scales: lvs. flattened, keeled above, 

 pale below 10. Keteleerta. 



DD. Scalr.x deciduous; seeds .shorter than 

 sciilis; hruc'ts shorter or longer: Iva. 

 flattened and grooved above, usually 

 glaucous below, rarely 4-iingled 11. Antes. 



3. Taxodium Tribe. 



A. Lva. connate into pairs, arranged in whorls: 

 ovule-bearing blade finally much increased 

 and hardened, malung the greater part of the „ „ . , ., 



woody, cone 12- Sciadopitys. 



AA. Lvs. solitary, scattered. 



B. Scales of cone flat. „ „ . 



c. Carpicles entire at apex: anther-cells 2-1: 

 seeds surrounded by a narrow wing: lvs. 

 lanceolate flat, rather large, glaucous 



below / ■ ■ • ■ I,- ^^- ^"""f"0- . 



CC. Carpicles toothed at the apex: anther-cells [hamia. 



4-5: seeds 2-3-angled: lvs. awl-shaped, 



curved !*■ Cryplamerm. 



BB. Scales peltate. ■ , , 



C. Seeds usually 5, narrowly winged: lvs. 



scale-like or linear, persistent 15. iiequoia. 



CC. Seeds 2, angular; Ivs. linear, deciduous 



with the branchlets 16. Taiodium. 



4. Cupressus Tribe. 



A. Fr. a cone. 



B. Cone-scales all fertile, 4-8, forming appar- 

 ently 1 whorl: Ivs. usually scale-like, 

 opposite or in whorls of 3 or 4, rarely _ ,,. . 



alternate on sterile branches .17. CaUilria. 



BB. Cone-scales fertile at middle of cone and 



sterile at top and base 18. f itznya. 



EBB. Cone-scales partly fertile, partly empty, 

 arranged in opposite pairs: lvs. scale-like, 

 opposite only on juvenile branches, some- 

 times needle-shaped. 

 C. Scales of cone imbricate. 



D. Seeds 4-5; pairs of scales 3-4 (exclud- 



ing the upper connate pair) 19. I huiopsia. 



DD. Seeds 2. ....,«« t l j 



E. Pairs of scales 4, the upper pair fertile.20. Libocedrus. 

 BE. Pairs of scales 6-8; the 2 upper pairs 



fertile 2L Thuja. 



cc. Scales of cone peltate. 



D. Number of seeds 2; cones small. ,„„„,. . 

 E. Wings of seeds very large, unequal. 22. tokienm. 



EE Wings of seeds narrow, equal 23. Chamiecyp- 



DD. Number of seeds many; cones usually [aris. 



rather large and woody .24. Cupressus. 



AA. Fr. fleshy, indehiscent berry or drupe, with 

 2-6 fertile scales: Iva. scale-like, opposite _ 

 or needle-shaped and usually in 3's 2o. Jumperus. 



Consult also the genus Athrotaxis, alUed to Celphalotaxus and 

 Sequoia. 



181. CYCADACE.E. 



A. Lf.-segms. circinately involute in vernation: 

 female cones proliferous after anthesis; 

 scales elongate, the margins bearing 2 to 



many ovules ; ■ ' • ■, Cycas. 



AA. Lf.-aegms. straight in vernation: female cones 



deciduous after anthesis; scales peltate. 



B. Cone-scales superposed in vertical series. 



c. Shield of the scales transversely 2-horned „ ^ _ 



at apex , • • ■, 2- Ceratozamia. 



cc. Shield of the scales truncate, not horned 



at apex ■ 3. Zamm. 



BB. Cone-scales overlapping in alternating 

 series. , , 



c. The lf.-segms. ribbed and nerved; nerves 

 spreading on either side of midrib, very 



numerous, simple or forked 4. Stangena. 



cc. The lf.-segms. with parallel, longitudinal 

 nerves. 

 D. Shield of cone-scales flat, erect, ovate- 



cordate ,; ■ 5. Dioon. 



DD. Shield thickened, ascending, usually 



Erolonged into an erect, acuminate 

 Ijjje 6. Macroiamia, 



DDD. Shield thickened truncate, decurved at 



aP« ■■ '■^'"''"[^L. 



The genera Bowenia and Microcycaa are also included. 



182. HYDROCHARITACE.ffi. 



A. St. elongated, submerged, everywhere leafy: 

 lvs. short- .spathes small, sessile in axils: 



placenta! little prominent in ovary •. • . L bloOta. 



AA St very short, sometimes emitting creeping 

 or floating stolons: Ivs. crowded, immersed, 

 sessile, elongated: spathes pedunculate: 

 placenta hardly prominent 2. VaUisnena. 



