Sonoma manzanita Arctostaphylos densiflora ‘Howard McMinn’, copyright Pete Veilleux.

Belongs within: Ericaceae.
Contains: Arctostaphylos subgenus Arctostaphylos.

The Arbutoideae are a Holarctic clade of shrubs and trees, including the strawberry trees and manzanitas, with fleshy, brightly coloured fruits.

Characters (from Kron et al. 2002): Trees or shrubs, usually evergreen. Leaves usually alternate, non-ericoid, entire or serrate, convolute in bud. Leaf epidermal cells not lignified. Indumentum of stalked glandular hairs and sometimes elongate, non-glandular hairs. Inflorescence terminal, racemose or paniculate; bracts present, bracteoles paired, more or less basal; calyx not articulated with pedicel. Flowers (4-)5-merous, actinomorphic. Calyx lobes small, persistent; corolla sympetalous, urceolate, with long unicellular hairs on the inside, the lobes small. Stamens (8-)10, included, the filaments more or less strongly dilated basally, more or less straight, unicellular-pubescent or smooth; anthers tetrasporangiate, inverting only just before anthesis, slightly roughened, with a pair of dorso-apical spurs, lacking a fibrous endothecium, lacking disintegration tissue, dehiscing by terminal pores or slit-like pores. Pollen in tetrads, without viscin threads. Ovary 4-10-locular, with axile placentation and only 1 to few ovules per locule, superior, sometimes with fleshy papillae; style continuous with the ovary; stigma truncate. Fruit more or less fleshy with bony or fibrous endocarp, a drupe or drupe-like berry; seeds with testa cells more or less elongated; embryo with 2 cotyledons.

<==Arbutoideae [Arbuteae]
    |--Ornithostaphylos oppositifoliaKJ02
    |    |--C. arbutoidesKJ02
    |    `--C. diversifoliaH93
    |         |--C. d. ssp. diversifoliaH93
    |         `--C. d. ssp. planifoliaH93
    |    |--A. andrachneDH98
    |    |--A. canariensisKJ02
    |    |--A. glandulosusBT87
    |    |--A. menziesiiKJ02
    |    |--A. unedoKJ02
    |    `--A. xalapensisSZ03
         |  i. s.: A. alpinaKJ02
         |--A. × helleri [A. myrtifolia × A. viscida]H93
         |--A. subg. ArctostaphylosH93
         `--A. subg. MicrococcusH93
              |--A. mendocinoensisH93
              |--A. myrtifoliaH93
              |--A. nissenanaH93
              `--A. nummularia [incl. A. nummularia var. sensitiva]H93

*Type species of generic name indicated


[BT87] Baker, E. W., & D. M. Tuttle. 1987. The false spider mites of Mexico (Tenuipalpidae: Acari). United States Department of Agriculture, Technical Bulletin 1706: 1–237.

[DH98] Danin, A., & I. C. Hedge. 1998. Contributions to the flora of Jordan 2. A new species of Satureja (Labiatae) and some new records. Willdenowia 28: 135–142.

[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).

[KJ02] Kron, K. A., W. S. Judd, P. F. Stevens, D. M. Crayn, A. A. Anderberg, P. A. Gadek, C. J. Quinn & J. L. Luteyn. 2002. Phylogenetic classification of Ericaceae: molecular and morphological evidence. Botanical Review 68: 335–423.

[SZ03] Sobek, E. A., & J. C. Zak. 2003. The Soil FungiLog procedure: method and analytical approaches toward understanding fungal functional diversity. Mycologia 95 (4): 590–602.

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