2866 



PYRUS 



PYRUS 



3270. Sessile fruit of Chasnomeles 

 Maulei. 



and the absence of fr.-stalk (Fig. 3270) afford good 

 structural characters, as well as the fl.-bearing habit 

 and other characters. Many of the species that have 

 been named under Pyrus will be found in Sorbus. 



If the genus is held 

 to comprise the pears 

 and apples and no 

 others (Pyrophorum 

 and Malus), there are 

 probably fifty or sixty 

 species. 



The aronias, by some 

 kept as a distinct genus 

 (page 396, Vol. I.), 

 comprise a small group 

 of North American 

 bushes with white flow- 

 ers in corymbs and 

 attractive little fruits. 

 Under Pyrus, the names are P. arbutifolia, Linn., the 

 red chokeberry; P. atropurpurea, Bailey, the purple 

 chokeberry, sometimes regarded as a variety of the 

 former; P. melanocarpa, Willd., the black chokeberry; 

 P. floribunda, Lindl. (not Hort.), of garden origin. 



The fruit of Pyrus is of the kind known to botanists 

 as a pome. The morphology of the pome is still perhaps 

 a subject of disagreement, although most botanists now 

 consider it to be a hollow torus (recep- 

 tacle), or hypanthium, or cupula, in 

 which the ovary is imbedded. Fig. 3271 

 illustrates the theoretical structure. The 

 ovary is at b, wholly inclosed in the 

 fleshy torus a. Most of the edible part 

 of the apple or pear, therefore, is con- 

 sidered to be torus, whereas the core is 

 ovary. This ovary, in common apples 

 and pears, is of five carpels or cells, as 

 shown in the cross-section (Fig. 3272). 

 It was formerly held that the edible part 

 is largely calyx-tube, but various mor- 

 phological considerations have inclined 

 students to regard it as stem rather than 

 calyx; the term calyx-tube is still re- -^ at b 

 tained, however, in descriptive writings. 

 One of these considerations is the fact that apples some- 

 times bear a rudimentary leaf (as in Fig. 3273), an 

 organ which is commonly borne only by stems. 



Apples sometimes take on most unusual and grotesque 

 shapes, and two or more fruits may coalesce into one. 

 Some of these forms, from an orchard of Pearmains, 

 are shown in Fig. 3274. These malformations may be 

 due in part to insufficient pollination, although such 

 teratologies are yet to be well explained. 



Aside from the pomological pears and apples, the 

 genus Pyrus as here defined includes many very attrac- 

 tive small trees and shrubs. The outlying pear species 

 are not much grown, although well worth cultivation for 



interesting foliage 

 and for good white 

 spring bloom. P. 

 salicifolia, P. elsea- 

 grifolia, and P. be- 

 tulsefolia are among 

 the best of these, 

 and the only ones 

 that are likely to ap- 

 pear in collections. 

 The silvery foliage 

 of the first two is 

 attractive. They are 

 hardy in the north- 

 ern states and prob- 

 ably in Ontario. 



It is among the 

 crab - apples, how- 

 ever, particularly of 



3271. Dia- 

 gram of a pome 

 (pear). Showing 

 the torus part at 

 a and the ovary 



3273. A pome bearing a 

 rudimentary leaf (at A). 



the Asiatic species, that the most ornamental plants 

 are to be found. Some of them, as P. pidcherrima (P. 

 floribunda) and P. Halliana, have long been popular, 

 but several others are fully as good and it is possible to 

 secure considerable variety. All the species included in 

 the numbers 21 to 36 in this account are probably hardy 

 in parts of New York state and some of them can be 

 grown in Canada. P. baccata is hardier even than the 

 common apple tree, and is therefore sometimes used for 

 stocks and as a parent in hybri- 

 dizing. All these crabs may be 

 raised as seedlings, for they 

 bloom profusely when only a 

 few years old, or they may be 

 grafted on any of the related 

 stocks. The Asiatic crabs are 

 profuse bloomers, and the pink- 

 and-white effect of blossoms 

 and buds as the leaves are un- 

 folding or just preceding the 

 leafage constitutes one of the 

 most charming prospects in the 

 spring plantation. Some of 

 them hold their small berry-like 

 fruits well into the winter, or even to spring, affording 

 a continuing interest. They are of the easiest culture in 

 well-drained soil. All the species are probably subject 

 to scale, and they should be well sprayed. Particularly 

 to be recommended for the central and northern 

 states east of the Great Lakes are P. pulcherrima, P. 

 Halliana, P. Scheideckeri, P. Sieboldii, P. prunifolia 

 var. Rinki, and P. Sargentii, the last a bush with pure 

 white flowers. 



The native American crabs, described in numbers 

 37 to 45 in this list, are yet little known to planters, but 

 they comprise much promising material, and they 

 should yield horticultural subjects for the entire area 

 of the United States, outside the semi-tropical regions, 

 and for good parts of Canada. As a class they bloom 

 later than the Asiatic species. As yet, only P. ioensis 

 appears to have yielded a good double-flowered form. 

 With the recent botanical discrimination in this inter- 

 esting group, attention will probably be called to a 

 closer study of the forms by collectors. They are easy 

 of culture, and may be readily increased by grafting. 



Hybridizing will probably play an important part in 

 the horticultural development of the ornamental crabs, 

 as they cross freely. It is probably due to this cause 

 that the Asiatic forms are so difficult to distinguish 

 botanically. The pears and apples appear not to inter- 

 cross, although the curious P. auricularis is generally 

 considered to be a hybrid between the pear and the 

 beam-tree (Sorbus Aria). 



The pear may be made to grow for a time when 

 grafted on the apple, but it is usually impossible to 

 graft the pear species permanently on the apple 

 species with any degree of success; yet pears thrive on 

 quinces and also on hawthorns, which are well-marked 

 genera. In nursery practice when pear stocks are not 

 at hand, long pear cions may be worked on apple 

 pieces and roots may form from the cion and the pear 

 become own-rooted on the failure of the apple stock. 

 Apples appear not to be successful on pears. 



3272. Section of a pome (apple). 

 Showing the interior or ovary part and 

 the exterior or torus part. 



