Hickories

Annamocarya sinensis A. Chevalier = Carya sinensis (Dode) J. Leroy "Cay Cho Dai", "Huei he tao" (Beaked walnut), Beaked hickory.

(This description is taken from Grauke, L.J.; Wood, B.W.; Payne, J.A. Genetic resources of Carya in Vietnam and China. Annu. Rpt. N. Nut Growers Assn. 82:80-87 (1991) and refers to the taxon as Carya sinensis. In later work, the species was classified as Annamocarya sinensis. (See Lu, A. M, Stone, D. E., and Grauke, L. J. Juglandaceae. p 277-285. In Wu Z. Y. and Raven, P. H. (eds) Flora of China, Volume 4, Cycadaceae through Fagaceae. Co-published by Science Press (Beijing) and Missouri Botanical Garden Press (St. Louis). 1999)

Carya sinensis was first described by Dode (1912) from herbarium collections in the Museum of Natural History in Paris sent by R. P Cavalerie from 'Kouy-Cheou' (=Guizhou), China. Dode based his determination entirely on characteristics of the nuts, since leaves and flowers were not available to him. He noted that "the attribution of the nuts to this genus seems to me in no way dubious", and compared them to "Carya alba Nutt." (=C. ovata (Mill.) K. Koch) and the European fossil species Carya maxima Saporta and Carya costata Unger. Dode concluded that "in no way does Carya sinensis constitute a completely remarkable type". His Latin description was brief: "Nut subglobose, large, 5 cm. tall, apiculate, not lacunose, obscurely ribbed, lightly lined, base depressed".

Subsequent researchers have not all accepted Dode's facile treatment of the taxon. The tree has been ascribed to six different genera: Annamocarya, Rhamphocarya, Juglandicarya, Caryojuglans, Juglans, and Carya (Manning & Hjelmqvist, 1951; Scott, 1953). Some students of the genus refer to the taxon as Carya sinensis Dode and place it in the monotypic Section Rhamphocarya, following the analysis of Manning & Hjelmqvist (1951). Others refer to the taxon as Annamocarya sinensis (Dode) Leroy, following the analysis of the French scientist Leroy (1950). The common name of the trees in Vietnam is "Cay Cho Dai". In China, the tree is called "Huei he tao", or "beaked walnut".

In China, C. sinensis has been collected from Tong-dao, Hunan (Hunan Research Group, 1988), San-hoa, Guizhou (Manning & Hjelmqvist, 1951), Guangxi (Kuang & Li, 1979; Hunan Research Group, 1988), and from various sites in Yunnan province (Manning & Hjelmqvist, 1951). In Vietnam, the tree is reported from the area of Lai Chau in the north, and southward in the region between the Song Ma and Da Rivers (Chevalier, 1941). It occurs in the Cuc Phuong Forest Preserve in Nho Quan district north of Thanh hoa and west of Nam Dinh. The species is reportedly cultivated in Taiwan and to some extent in Vietnam (Kuang & Li, 1979). Plantings of the trees, approximately 14 yrs. old, are at Cuc Phuong.

On September 22, 1990, we collected from trees at the Cuc Phuong National Forest. We were accompanied by the Vietnamese scientists Vu Van Dung (Botanist), Nguyen Ngoc Chinh (Botanist), Nguyen Ngoc Nhi (Ecologist), Dang Van Dam (Engineer), and Nguyen Ba Thu (Director of Cuc Phuong). We found no viable nuts under the mature, forest grown trees of Carya sinensis we visited. Trees were in a dense forest, with very little light penetrating to the forest floor. The canopy of the trees was high overhead and inaccessible to us, since the large, smooth, tapered trunk offered no means of ascent. On the ground under the canopy we found numerous fruits which had been damaged by animals. An orchard of the species was planted at Cuc Phuong about 14 years ago, and we collected herbarium materials and the two available nuts from those trees. Trees ranged in size from 15-30 cm dbh (diameter breast high) . A parasite, identified as a Chloranthus species, was growing in some of the trees. The surface soil was reddish brown in color with a pH of 5.5. At 30 cm the soil had the same pH, and the color was slightly lighter.

The tree has persistent leaves, a feature which lead Chevalier (1941) to describe it as 'evergreen'. When we saw the trees, new growth was flushing while old leaves were still present. The bark is grayish white and smooth, even on old trees. Old trees have prominent buttresses where roots join the trunk. Some of the roots are visible for over 10 m from the trunk. In his description of Annamocarya indochinensis(=Carya sinensis), Chevalier (1941) described the trunk as "winged", evidently in respect to this character.

Leaves are odd pinnately compound, with 7-9 leaflets which have entire margins. All other Carya species have serrate leaf margins. Petioles have lateral ridges and may appear grooved on top, especially on young leaves. The junction with the stem is enlarged. Young shoots have solid pith, but mature shoots of the current season's growth are hollow, a feature also reported by Leroy (1955). Ants and other insects have been found in the hollow shoots.

Manning (1978) noted that Carya sinensis Dode is the most primitive member of the genus Carya, based on botanical studies of several features conducted by many researchers. Manning and Hjelmqvist (1951) noted that catkins are borne in bundles of five, which is unusual in the genus: other species bear 3 catkins per bundle. According to Kuang & Li (1979), 2-3 male inflorescences may arise from a single leaf axil, on current years growth. There are an unusually large number of stamens in male flowers (5-15) as compared to other species (3-8, usually 4)(Manning and Hjelmqvist, 1951). Female flowers differ from other species of Carya in that the stigma is not sessile, and no stigmatic disk is present.

Husks may separate into as many as 9 segments in C. sinensis, more than in any other Carya species. Each segment of the husk has a prominent longitudinal rib or keel. The nut is characterized by a prominent apex, which gives the tree its common name in Chinese, "beaked hickory". An elevated ridge marks the suture, near the apex on the sides of the nut. The base of the nut is unusual for its prominent basal plexus, which appears "pinched", or laterally depressed. Nuts are very large (6.8 cm X 4.8 cm ) and also have thick shells (3-4 mm). Shells seem more porous than in North American species of Carya. The vascular bundles which come from the shuck to nourish the developing kernel (funicular strands) are scattered around the inner periphery of the shell in Carya sinensis, rather than following along the outer margin of the primary septum as in other Carya species. Leroy (1955) considered the organization of funicular strands in the shell to be the most important reason for separating this species from Carya as the genus Annamocarya.

We support the efforts of Vietnamese foresters to preserve the genetic resources of Vietnam and recognize Cuc Phuong National Forest as an important in situ repository for the preservation of Carya sinensis.

LJ Grauke , Research Horticulturist & Curator
USDA-ARS Pecan Genetics
10200 FM 50
Somerville, TX 77879
tele: 979-272-1402
fax: 979-272-1401
e-mail: ljg@tamu.edu

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