Trees of New York State 355 



THE HICKORIES. Genus CAllYA Nutt. 



Trees with aromatic watery sap, tougli liexuoiis branches, alter- 

 nate odd-pinnately compound leaves, ton<>h clastic wood and homo- 

 j?eneous pith. The genus is endemic to the temperate region of 

 the eastern United States and includes twelve species, eleven of 

 which occur within the boundaries of this country. 



Leaves alternate, odd-pinnately compound; leaflets ovate or nlxnate, gener- 

 ally acuminate, inequilateral at the base, seri-ate, sessile (ji- short-stalked 

 aside from the terminal and arrangetl in pairs long a rachis. Flowers 

 monocious, vernal; staminate flowers in slender drooping aments borne in 

 pedunculate clusters of 3 on the base of the growth of the season or near the 

 summit of the growth of the preceding season; perianth adnate to tlie bract, 

 2-3 lobed or cleft; stamens 3-10; pistillate flowers in 2-10-flowered, terminal 

 spikes; perianth unequally 4-lobed, adnate to the ovary; stigmas short-papil- 

 lose. Fruit a. subglobose, oblong, ovoid or pyriform nut with dehiscent, 

 4-valved exocarp and a. bony endocarp which is 4-celled at the base and 2- 

 celled at the apex. Seed variously lobed, exalbuminous, oily, generally edible. 



KEY TO THE SPECIES page 



1 , Bud -scales few, valvate; latenxl leaflets usually curved C. cordiformis 155 



1. Bud-scales numerous, valvate; lateral leaflets slightly, if at all falcate 2 



2. Husk of the fruit thick, splitting to the base 3 



2. Husk of the fruit thin, usually not splitting to the base 5 



3. Bark close and rough; foliage stellate pubescent C. alba 149 



3. Bark shagg>', exfoliating in long, loose plates 4 



4. Leaflets generally 3-5; twigs orange-lenticellate C. laciniosa 147 



4. Leaflets generally 7-9; twigs pale lenticeUate C. ovata 145 



5. Fruit nearly globose; bark of old trunks exfoliating in long strips 



C. microcarpa 151 



5. Fruit obovoid or pyriform; bark close, not exfoliating in long strips 



C. glabra 153 



BIRCH FAMILY. BETULACEAE 



Trees or shrubs with watery juice, alternate, petioled, simple, 

 stipulate leaves, monoecious or rarely dioecious flowers and a 

 fruit which is a small winged or unwinged nut. The Betulaceae 

 are indigenous to the cooler portions of the northern hemisphere 

 and include 6 genera and approximately eighty species. Three 

 genera are represented by arborescent forms in New York State. 



Leaves alternate, deciduous, simple, stipulate (stipules generally fugacious), 

 pinniveined. Flowers monecious, vernal, appearing before or with the leaves ; 

 staminate flowers in elongated pendulous lateral aments, borne in clusters of 

 1-G in the axils of bracts; perianth present or wanting; stamens 2-20 erect, 

 inserted on a receptacle, with short filaments and oblong anthers; pistillate 

 flowers in short, spike-like or capitate aments, borne in clusters of 1-3 in the 

 axils of bracts; perianth present or wanting; pistil consisting of a 2-celled 

 ovary terminated by a 2 -cleft style, the lobes stigmatic at the apex or on the 

 inner surface; ovule solitary, pendulous. Fruit a small, mostly 1-celled, 



