454 PLATANACEAE (PLANE TBEK FAMILY) 



PLATANACEAE (Plane Tree Family) 



Trees, with watery juice, alternate palmately-lobed leaves, sheathing stipules, 

 and monoecious flowers in separate and naked spherical heads, destitute of calyx 

 or corolla ; the fruit merely club-shaped 1-seeded nutlets, furnished with a ring 

 of bristly hairs about the base. Only the following genus (of uncertain rela- 

 tionsliip). 



1. PLAtANUS [Tourn.] L. Stcamoee. Buttonwood 



Sterile flowers of numerous stamens, with club-shaped little scales inter- 

 mixed ; filaments very short. Fertile flowers in separate catkins, consisting of 

 inversely pyramidal ovaries mixed with little scales. Style rather lateral, awl- 

 shaped or thread-like, simple. Nutlets coriaceous, small, tawny-hairy below, 

 containing a single orthotropous pendulous seed. Embryo in the axis of thin 

 albumen. — Large trees, with the bark deciduous in broad thin brittle plates ; 

 dilated base of the petiole inclosing the bud of the next season. (The ancient 

 name, from v'KaTM, broad.) 



1. P. occident^lis L. Leaves mostly truncate at base, angularly sinuate- 

 lobed or toothed, the short lobes sharp-pointed ; fertile heads solitary, hanging 

 on a long peduncle. — Rich soil, s. Me. to n. Vt., Ont., s. e. Minn., e. Kan., and 

 southw. — Our largest tree, often 25-40 m. high, with a trunk 2-4.2 m. in 

 diameter. 



ROSACEAE (Rose Family) 



Plants with regular flowers, numerous (rarely few") distinct stamens inserted 

 on the calyx, and 1-many pistils, which are quite distinct, or (in the second 

 tribe) united and combined with the calyx-tube. Ovules (anatropous) 1-few in 

 each ovary ; s^eds almost always without albumen. Embryo straight, with large 

 and thick cotyledons. Leaves alternate, loith stipules, these sometimes caducous, 

 rarely obsolete or wanting. — Calyx of 5 (3-8) sepals (the odd one superior), 

 united at the base, often appearing double by a row of bractlets outside. Petals 

 as many as the sepals (rarely wanting), mostly imbricated in the bud, and in- 

 serted with the stamens on the edge of a disk that lines the calyx-tube. Trees, 

 shrubs, or herbs. 



Tribe I. SPIRAfeEAE. Ovary superior and not inclosed in a calyx-like tube ; carpels 1-12, dry at 

 maturity and (in ours) dehiscent, 2-several(rar6ly 1)-Beeded. 



* Carpels inflated ; leaves simple, often palmately lobed. 



1. Physocarpus. Stamens oo, in several rows. Carpels 3-5, splitting Into 2 valves. Beeds with 



hard shining coat. Shrubs, 



* * Carpels not inflated. 

 4- Carpels alternate with (or of a different number from) the sepals or calyx -lobes. 



2. Spiraea. Stamens on the margin of a disk-like expansion of the floral axis. Carpels splitting 



chiefly along the ventral suture. Leaves simple. Shrubs. 

 8. Aruncus. Dioecious. Stamens borne on the upper (inner) surface of a disk-like expansion of 



the floral axis. Leaves compound. Herbs. 



+■ +■ Carpels (normally 6) opposite the 6 sepals or calyx-lobes. 

 4. Sorbaria, Petals imbricated in bud. Seeds pendulous. Flowers small, corymbose. 

 6. Gillenia Petals convolute in bud. Seeds ascending. Flowers long-peduncled. 



Tribe II. p6MEAB. Carpels few, mostly definite (2-5) and usually connate, borne within and 

 adnate to a cup-like or urn-like depression in the enlarged summit of the floral a.xis (resembling 

 a calyx-tube), the whole united to form a fleshy fVuit. Trees and shrubs, with stipules free 

 from the petiole. 



